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Accelerated corrosion of 316L stainless steel in simulated body fluids in the presence of H 2 O 2 and albumin

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Abstract

316L stainless steel has been widely used for orthopedic devices. Inflammatory response and direct contact with abundant proteins after implantation lead to corrosion issues of biomedical stainless steels. The effect of combination of H2O2 and albumin on the corrosion of 316L stainless steel has been investigated for the first time in simulated body fluids at 37 °C with electrochemical and long term immersion tests. ICP-MS measurement after 16 weeks immersion reveals that the total concentration in the presence of both species was substantially higher than physiological saline alone, and even higher than the sum of H2O2 alone and albumin alone. Electrochemical polarisation curves and electrochemical impendence spectra show that albumin accelerated anodic dissolution and suppressed cathodic reaction, while H2O2 promoted cathodic reaction. Also, H2O2 and/or albumin promoted meta-stable/stable pitting corrosion and decreased charge transfer resistance. Accelerated corrosion of 316L stainless steel in the presence of both species was attributed to the promoted formation of Fe oxides and CrOOH by H2O2 and the largely favoured dissolution of these oxides by the addition of albumin, significantly accelerating Fe and Cr release. The synergistic interaction between both species indicates significant underestimation of corrosion rate evaluated solely in physiological saline. These findings suggest the necessity of using more realistic solutions to evaluate corrosion resistance of biomedical alloys for future in-vitro studies.

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... Nevertheless, after exposure to physiological media and upon interaction with proteins, inadequate osseointegration and osteoconductivity as well as increased metal-ion release have been reported for these materials [7,10]. Cathodic and anodic electrochemical reactions on the oxide film of titanium and its alloys in physiological media lead to the reduction of oxygen, which proceeds through partial reactions with radicals and hydrogen peroxide (H 2 O 2 ) [11,12]. Moreover, the activation of inflammatory cells, particularly macrophages and neutrophils (which are the first cells that adsorb onto the implant surface), trigger the production of high amounts (i.e. ...
... Moreover, the activation of inflammatory cells, particularly macrophages and neutrophils (which are the first cells that adsorb onto the implant surface), trigger the production of high amounts (i.e. µM-mM) of reactive oxygen species (ROS) and extracellular H 2 O 2 [10,12]. The presence of ROS and H 2 O 2 further complicates the electrochemical reactions and metal-ion release at the oxide layer/protein interface [13]. ...
... In practice, owing to the synergistic effect of inflammatory conditions, the electrochemical potential value of metallic implants, such as CoCrMo, stainless steel, and Ti6Al4V alloys, can shift towards less positive values (e.g. + 500 mV) [12,13,56]. To assess the interplay between H 2 O 2 and BSA and their corresponding effect on the electrochemical response of the implant surface, PDP measurements were performed in electrolytes containing only PBS, PBS + H 2 O 2 , PBS + BSA, or PBS + H 2 O 2 + BSA, the results of which are presented in Fig. 4. As can be seen in this figure, the presence of 1 g⋅L -1 BSA in the PBS solution decreases the corrosion potential (E corr ) by lowering the cathodic reaction branch. ...
Article
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Protein adsorption on the surface of implant materials greatly affects the performance of the implants, such as their stability as well as the release of metal ions from and the adhesion of cells to their surface. In addition, the production of extracellular H2O2 from the activation of inflammatory cells could interfere with protein-metal interactions and/or modify the conformation of adsorbed proteins. In this study, we utilised scanning Kelvin probe force microscopy (SKPFM) to visualise the impact of H2O2 on bovine serum albumin (BSA) adsorption on the positively polarised Ti6Al4V alloy in a phosphate-buffered saline (PBS) solution. We show that the negatively charged BSA adsorbs onto the surface of polished and anodically polarised Ti6Al4V in a dense layer with a continuous network-like morphology or cluster shape and reduces the variation in the total surface potential compared to that of blank Ti6Al4V. However, addition of H2O2 to the PBS solution interferes with the formation of the dense protein network, and only a thin and discontinuous protein layer adsorbs onto the surface of the Ti6Al4V alloy, lowering the total surface potential difference. The information presented in this work provides new insights into the adsorption distribution of proteins on metallic substrates in biomaterials field.
... For the impedance spectra measured on the tested surfaces, only one time constant was observed and therefore a single loop circuit ( Figure 3) consisting of electrolyte resistance (R Ω ), charge transfer resistance (R ct ), and the constant phase element (CPE) was used for the evaluation. The same circuit was also used for stainless steels by authors [29][30][31][32]. If the "n" exponent appearing in the mathematical relation expressing the CPE is equal to one, the CPE represents the capacitor. ...
... If the "n" exponent appearing in the mathematical relation expressing the CPE is equal to one, the CPE represents the capacitor. The CPE value depends on parameters related to the rate of on- The same circuit was also used for stainless steels by authors [29][30][31][32]. If the "n" exponent appearing in the mathematical relation expressing the CPE is equal to one, the CPE represents the capacitor. ...
... The dependence of impedance modulus |Z| and phase angle Φ on the measured frequency is shown in the form of Bode plots for different surface modifications, as shown in Figure 4. The same circuit was also used for stainless steels by authors [29][30][31][32]. If the "n" exponent appearing in the mathematical relation expressing the CPE is equal to one, the CPE represents the capacitor. ...
Article
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Plasma electrolytic polishing (PEP) is an environment-friendly alternative to the conventional electrochemical polishing (EP), giving optimal surface properties and improved corrosion resistance with minimum energy and time consumption, which leads to both economic and environmental benefits. This paper is focused on the corrosion behavior of PEP treated AISI 316L stainless steel widely used as a biomaterial. Corrosion resistance of plasma electrolytic polished surfaces without/with chemical pretreatment (acid cleaning) is evaluated and compared with original non-treated (as received) surfaces by three independent test methods: electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), and exposure immersion test. All corrosion tests are carried out in the 0.9 wt.% NaCl solution at a temperature of 37 ± 0.5 °C to simulate the internal environment of a human body. The quality of tested surfaces is also characterized by optical microscopy and by the surface roughness parameters. The results obtained indicated high corrosion resistance of PEP treated surfaces also without chemical pretreatment, which increases the ecological benefits of PEP technology.
... Considering that corrosion and tribocorrosion (the combined action of wear and corrosion) phenomena are reported as degradation mechanisms of biomedical alloys in the human body, the impact of albumin on the final corrosion and the tribological response of implants is one of the main motivations for better understanding the interaction of albumin with biomedical alloys. Indeed, the literature reports that albumin affects the corrosion behavior of biomedical alloys by different mechanisms such as accelerating their dissolution [24,[26][27][28][29][30][31][32][33] or acting as cathodic inhibitor [34]. Additionally, it also is indicated that albumin might affect the tribological response of the alloys by producing a lubricating effect with the formation of a tribofilm [35][36][37] or changing the viscosity of the fluid and the structure of the double layer [38]. ...
... EDS and WDS are used for qualitative and quantitative chemical analysis of the surface oxide and organic layers [26][27][28][29][30]34,44,46,47,51,52,54,55], while XPS and AES additionally provide depth resolution, thus information on the thickness and chemical composition of these layers [29]. The influence of protein adsorption on the surface chemistry of CoCrMo alloys have been studied combining in-situ electrochemical techniques and ex-situ surface analysis [29,34]. ...
... Additionally, metal release induced by protein-metal binding also depends on other parameters, such as adsorption mechanisms, metal atom availability in the surface oxide, stability constants of protein surface groups and metal ions [3,90], protein concentration [91] and the temperature of the solution [26]. Albumin was reported to bind to Fe [28,54], Cr [27,[91][92][93][94], Ni [26,51], Co [26,27], Mo [54], Ti [51,54], Al [95][96][97], and V [53]. ...
Article
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Understanding the interactions between biomedical alloys and body fluids is of importance for the successful and safe performance of implanted devices. Albumin, as the first protein that comes in contact with an implant surface, can determine the biocompatibility of biomedical alloys. The interaction of albumin with biomedical alloys is a complex process influenced by numerous factors. This literature overview aims at presenting the current understanding of the mechanisms of serum albumin (both Bovine Serum Albumin, BSA, and Human Serum Albumin, HSA) interactions with biomedical alloys, considering only those research works that present a mechanistic description of the involved phenomena. Widely used biomedical alloys, such as 316L steel, CoCrMo and Titanium alloys are specifically addressed in this overview. Considering the literature analysis, four albumin-related phenomena can be distinguished: adsorption, reduction, precipitation, and protein-metal binding. The experimental techniques used to understand and quantify those phenomena are described together with the studied parameters influencing them. The crucial effect of the electrochemical potential on those phenomena is highlighted. The effect of the albumin-related phenomena on corrosion behavior of biomedical materials also is discussed.
... Increasing concern regarding the consequences of metal release from biomedical implants has stimulated efforts to better understand the conditions under which corrosion occurs, and the nature of the corrosion products that are released (Xu et al., 2018;Morrell et al., 2019;Xu et al., 2019). Oxidation-resisting steel, Co-Cr and Ti alloys are the most common biomedical implant metals in use today (Sullivan and Topoleski, 2015;Harun et al., 2017;Xu et al., 2018;Xu et al., 2019). ...
... Increasing concern regarding the consequences of metal release from biomedical implants has stimulated efforts to better understand the conditions under which corrosion occurs, and the nature of the corrosion products that are released (Xu et al., 2018;Morrell et al., 2019;Xu et al., 2019). Oxidation-resisting steel, Co-Cr and Ti alloys are the most common biomedical implant metals in use today (Sullivan and Topoleski, 2015;Harun et al., 2017;Xu et al., 2018;Xu et al., 2019). Of these, Ti in its commercially pure and alloyed forms is mostly used for "cementless" implants because of titanium's ability to "osseointegrate" with bone, provide adequate mechanical properties, and exhibit resistance to corrosion under normal physiological conditions (Paka and Pokrowiecki, 2018;Kang and Yang, 2019;Rabadia et al., 2019;Zhang and Chen, 2019;Zhang L.-C. et al., 2020). ...
Article
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Ti alloys have been widely used in biomedical field due to good compatibility and corrosion resistance. However, corrosion-related failures of implanted Ti devices and prostheses have been regularly reported within the medical literature. The corrosion of Ti alloys has attracted much attention in vivo and in vitro. In the current study, the corrosion behavior of Ti6Al4V alloy was investigated using surface analysis and electrochemical tests. Corrosion of Ti6Al4V in 2 M hydrochloric acid is temperature dependent within the temperature range studied. It has found that the steady state current density at −510 mV vs. SCE (the primary passivation potential at the physiological temperature of 37°C) becomes higher with increasing temperature. The α phase of Ti6Al4V is preferentially dissolved relative to the β phase after potentiostatic measurement at primary passivation potential in 2 M HCl at 37°C. This investigation provides novel and useful information for Ti corrosion-related failures of biomedical implants and prostheses.
... 3,4 However, the physiological media of the human body constitute a complex corrosive environment consisting of various ions, proteins, and cells in which different alloys such as the most used Ti6Al4V, CoCrMo, or stainless steels are susceptible to degradation and corrosion following different mechanisms. [5][6][7] When an implant is exposed to the environment in a human body, protein is initially adsorbed, which in turn plays a predominant and determinative role in subsequent interactions. 8,9 Tissue compatibility and cell adhesion are both controlled by the initial interaction between serum proteins and the implant. 2 The conformation and amount of the protein layer adsorbed on the implant are both influenced by surface properties such as the surface energy, topography, hydrophobicity, and chemical composition of the metal oxide layer on the implant. ...
... Notably, gradually increasing the BSA protein concentration from 0.5 to 2 g l −1 decreased i pass , suggesting that at low concentrations, the complexing effect of the BSA molecules with the metal substrate plays a major role leading to greater dissolution or metal-protein complex detachment, while at higher BSA concentrations, more protein is absorbed on the surface, thereby providing a shielding effect. 1 Under physiological conditions in the human body, inflammatory cells can release reactive oxygen species (ROSs), thus increasing the degradation of implant materials. 7 According to the results of previous studies conducted under simulated inflammation conditions, the electrochemical potential of the CoCrMo alloy can positively shift from −0.1 to +0.65 V owing to the Fenton reaction and the formation of hydrogen peroxide (H 2 O 2 ). 25 Therefore, we polarized the CoCrMo samples for 1 h at anodic potentials +100 mV and +300 mV vs Ag/AgCl (compared to OCP as a reference) in all the tested solutions. Then, EIS was used to visualise the simultaneous influences of the passive film growth, protein adsorption on the positively charged passive film, and material degradation (i.e. ...
Article
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The protein adsorption and both its conformational arrangements and electrochemical interactions on the surface of metallic biomaterials has an immense impact on corrosion/biodegradation and biocompatibility of implantable metals. In this study, we used scanning Kelvin probe force microscopy (SKPFM) to reveal the synergistic effect of various bovine serum albumin (BSA) concentrations and overpotential conditions on BSA protein adsorption mechanisms and its influence on the corrosion behaviour of the CoCrMo alloy in phosphate-buffered saline solution. Electrochemical measurements showed that CoCrMo alloy was more resistant to corrosion in the 2 g L−1 BSA protein medium than in the 0.5 g L−1 one. The SKPFM analysis revealed a lower surface potential on the regions where BSA was adsorbed forming clusters, than on the un-covered CoCrMo substrate. When the surface overpotential and the protein concentration were increased from the OCP to +300 mV vs. Ag/AgCl and from 0.5 to 2 g L−1, respectively, on both protein covering and surface potential were increased. Field emission scanning electron microscopy indicated that localized corrosion eventually occurred at the BSA protein/substrate interface owing to the adsorption of counterions and the difference between the surface potential values.
... The effect of proteins such as bovine serum albumin (BSA), human serum albumin (HSA) on the degradation of different passive metals such as CoCrMo [40][41][42] , Ti6Al4V [ 39 , 43-45 ] and AISI 316 L SS [46][47][48] has also been investigated. The impact of protein on the corrosion of passive alloys and the metal ions release in body fluids is determining [49] . ...
... The impact of protein on the corrosion of passive alloys and the metal ions release in body fluids is determining [49] . For instance, it has been reported that the albumin protein can accelerate the anodic dissolution and suppress the cathodic reactions of SS 316 L (Low carbon) 0.9% NaCl solution [48] . Another study reports that the presence of BSA or lysozyme in PBS solution increases the Fe, Cr, Ni and Mn release from stainless steels (AISI 304, 310 and 316 L) reducing their corrosion resistance [47] . ...
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The field of biomedical small-scale swimmers has made major progress during the last two decades. While their locomotion aspects and functionalities have been demonstrated, there are key aspects that have been often overlooked such as their service live durability, which difficult their translation to the clinics. Several swimmers consist of combinations of metals and alloys that, while they excel in their functionalities, they fail in their stability due to corrosion in highly aggressive complex body fluids. Here, for the first time the corrosion mechanism of a widely employed design in magnetic microrobots, a gold-coated magnetic NiCo alloy, is assessed. A systematic approach by combining electrochemical and surface analysis techniques is reported, which shed light on the degradation mechanisms of these systems in simulated body fluids. While results demonstrate that Au coatings remarkably enhance the surface nobility and resistance to corrosion/biodegradation of NiCo in an aggressive environment containing albumin protein, Au coatings' intrinsic defects lead to a galvanic coupling with the NiCo substrate. The coordination of protein with NiCo further accelerates corrosion causing morphological changes to the swimmers' surface. Yet, the formation of a phosphate-based layer acts as a barrier to the metal release after long immersion periods.
... The "L" in 316L stainless steel denotes low carbon content, which can intercept the formation of chromium carbides and increase the corrosion resistance. However, stress corrosion cracking, which cannot be prevented in 316L stainless steel, can be triggered by the combined effect of tensile stress and a Cl-rich environment such as human body fluid, resulting in an undesirable sudden failure of the implant under stresses [6]. Moreover, although Co-Cr-based alloys have a higher corrosion resistance compared to 316L stainless steels in human body fluid, some undesirable ions such as Cr and Co are released due to wear and corrosion [7]. ...
Article
Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950s. Due to the excellent mechanical tribological properties, corrosion resistance, biocompatibility, and antibacterial properties of titanium, it is getting much attention as a biomaterial for implants. Furthermore, titanium promotes osseointegration without any additional adhesives by physically bonding with the living bone at the implant site. These properties are crucial for producing high-strength metallic alloys for biomedical applications. Titanium alloys are manufactured into the three types of α, β, and α + β. The scientific and clinical understanding of titanium and its potential applications, especially in the biomedical field, are still in the early stages. This review aims to establish a credible platform for the current and future roles of titanium in biomedicine. We first explore the developmental history of titanium. Then, we review the recent advancement of the utility of titanium in diverse biomedical areas, its functional properties, mechanisms of biocompatibility, host tissue responses, and various relevant antimicrobial strategies. Future research will be directed toward advanced manufacturing technologies, such as powder-based additive manufacturing, electron beam melting and laser melting deposition, as well as analyzing the effects of alloying elements on the biocompatibility, corrosion resistance, and mechanical properties of titanium. Moreover, the role of titania nanotubes in regenerative medicine and nanomedicine applications, such as localized drug delivery system, immunomodulatory agents, antibacterial agents, and hemocompatibility, is investigated, and the paper concludes with the future outlook of titanium alloys as biomaterials. Graphic abstract:
... The extent of metal release (migration) from stainless steel in food environments is governed by different mechanisms and processes including corrosion (metal oxidation), pitting corrosion, and complexation-induced metal release [14][15][16][17][18][19][20][21][22][23]. It has been hypothesized that i) metal release is preceded and triggered by the adsorption of proteins [24], ii) protein exchange might increase (and in some cases reduce) the extent of corrosion [20,25], iii) adsorbed proteins can act as beneficial lubricants in the case of wear processes [26], and iv) that the adsorption of proteins can contribute to the mechanisms of tribocorrosion via complexation with metals within the surface oxide [11]. ...
Article
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Reactions at the biointerfaces between stainless steel and protein-rich dairy products, which contain whey proteins, are important to consider in terms of food safety and material grade selection. Changes in corrosion behavior, metal release, and surface composition of austenitic (AISI 316 L), ferritic (AISI 430), and lean duplex (LDX 2101) stainless steels in simulated milk (SMS) and whey protein solution were investigated. The amount of released metals and the corrosion susceptibility increased according to 2101 < 316 L < 430. All grades revealed low corrosion rates in the whey protein solution without any sign of active/metastable corrosion. Pitting corrosion was evident for 430 in SMS. The total amount of released metals (iron, chromium, and nickel) was significantly higher in whey protein solution compared with SMS. This suggests the metal release process to be mainly governed by complexation reactions. Nickel was preferentially released compared to its bulk composition fraction for both 316 L and 2101 in the highly complexing SMS. Reduced metal release rates with time correlated with the enrichment of chromium in the surface oxide. The extent of metal release was for all metals substantially lower than release limits of metals stipulated in health regulations related to the use of alloys and metals in food-related environments.
... Cooner wires (316LVM stainless steel alloy with Teflon insulation), for instance, have been used in numerous rodent and human studies as intramuscular stimulation and recording electrodes [11][12][13][14][15][16][17]. Despite the fact that some types of stainless-steel wires are more prone to electrochemical corrosion [18,19], they have high strength, low electrical resistivity, a high-charge injection limit, and minimal passive tissue response [20][21][22]. A notable design is the intramuscular electrode designed by Memberg et al.; the conducting core consists of a coiled SS alloy, insulated with a fluoropolymer, and secured in vivo with propylene tines [15]. ...
Article
Electrical stimulation of the muscle has been proven efficacious in preventing atrophy and/or reanimating paralyzed muscles. Intramuscular electrodes made from metals have significantly higher Young's Moduli than the muscle tissues, which has the potential to cause chronic inflammation and decrease device performance. Here, we present an intramuscular electrode made from an elastomeric conducting polymer composite consisting of PEDOT-PEG copolymer, silicone and carbon nanotubes (CNT) with fluorosilicone insulation. The electrode wire has a Young's modulus of 804 (±99) kPa, which better mimics the muscle tissue modulus than conventional stainless steel (SS) electrodes. Additionally, the non-metallic composition enables metal-artifact free CT and MR imaging. These soft wire (SW) electrodes present comparable electrical impedance to SS electrodes of similar geometric surface area, activate muscle at a lower threshold, and maintain stable electrical properties in vivo up to 4 weeks. Histologically, the SW electrodes elicited significantly less fibrotic encapsulation and less IBA-1 positive macrophage accumulation than the SS electrodes at one and three months. Further phenotyping the macrophages with the iNOS (pro-inflammatory) and ARG-1 (pro-healing) markers revealed significantly less presence of pro-inflammatory macrophage around SW implants at one month. By three months, there was a significant increase in pro-healing macrophages (ARG-1) around the SW implants but not around the SS implants. Furthermore, a larger number of AchR clusters closer to SW implants were found at both time points compared to SS implants. These results suggest that a softer implant encourages a more intimate and healthier electrode-tissue interface. Statement of significance Intramuscular electrodes made from metals have significantly higher Young's Moduli than the muscle tissues, which has the potential to cause chronic inflammation and decrease device performance. Here, we present an intramuscular electrode made from an elastomeric conducting polymer composite consisting of PEDOT-PEG copolymer, silicone and carbon nanotubes with fluorosilicone insulation. This elastomeric composite results in an electrode wire with a Young's modulus mimicking that of the muscle tissue, which elicits significantly less foreign body response compared to stainless steel wires. The lack of metal in this composite also enables metal-artifact free MRI and CT imaging.
... Moreover, the addition of albumin inhibits Ni release in H 2 O 2 -containing solution. While the difference in release amount of Fe, Cr and Mn into physiological saline with and without albumin is negligible [53], it may be ascribed to the albumin adsorption on the material surface, which may block some active sites for reactions between Ni and H 2 O 2 [41]. Since Ni exists as metallic Ni enriched in alloy matrix under surface oxide layer [41], the adsorbed albumin may not be able to have direct access to react with Ni metal in base metal and facilitate its release. ...
Article
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The stainless steel alloys are greatly utilized for human orthopaedic and implants. The electrochemical behaviour of the stainless steel of Fe–17Cr–xNi alloys (x = 8, 10, 14) has been studied in simulated body fluid containing H2O2 and albumin at 37 °C. The electrochemical behaviour of the Fe–17Cr–8Ni, Fe–17Cr–10Ni and Fe–17Cr–14Ni has been investigated using the potentiodynamic polarization and electrochemical impedance spectroscopy, EIS. The surface morphology of the three alloys was examined before and after immersion in the simulated body fluid containing H2O2 and albumin using scanning electron microscope. The elemental composition of the oxide layer formed on the surface of the alloys after immersion in the electrolyte was obtained using energy dispersive X-ray analysis, EDX, technique. The metals released into the electrolyte has been determined using atomic absorption spectrophotometry. The EIS and potentiodynamic polarization results demonstrate that the Fe–Cr–14Ni alloy attains highest polarization resistance and the smallest rate of corrosion than Fe–17Cr–8Ni and Fe–17Cr–10Ni alloys. Fe–17Cr–14Ni is slightly influenced by immersion in simulated body fluid containing H2O2 and albumin which is confirmed by SEM images and metal release via formation of protective passive film. The surface analysis has shown the participation of the different alloying elements in the passive film. Graphic Abstract
... The Fe 2p results of the corrosion products on the surface of the three pipeline steels were similar, producing the same corrosion products. The Fe 2p spectrum obviously larger peaks of Fe 2 O 3 2p3/2 at 711.0 eV and Fe 2 O 3 satellite at 718.8 eV [26][27][28], FeOOH 2p3/2 at 711.8 eV [29,30], and FeCO 3 2p3/2 at 711.9 eV and FeCO 3 2p1/2 at 725.5 eV [31,32], FeS 2p3/2 at 713.6 eV [33]. Regardless of the environment, the XPS peaks correspond to Fe 2 O 3 , FeOOH, FeCO 3 , and FeS, which are typical corrosion products on carbon steel [34]. ...
Article
Pipeline transportation is one of the five major modes of transportation. Inner corrosion problems in product oil pipelines are widespread but have not received attention, and high strength product oil pipelines are rarely used in China. In this paper, morphology and composition analysis and electrochemical methods were used to study the corrosion behaviors and characteristics of API 5L X65, X70 and X80 steel product oil pipelines. The feasibility of using high strength product oil pipelines in the transportation environment of product oil under the condition of inner corrosion is discussed, and the support for the safe operation of product oil pipelines is provided. The research results show that X80 pipeline steel has advantages over X65 and X70 pipeline steel. In the simulated liquid system of sediments in product oil pipeline, as the immersion time increases, the corrosion rate of X65, X70 and X80 pipeline steels shows a trend from high to low. Morphological analysis and electrochemical analysis showed that X80 pipeline steel showed better performance and adaptability to the environment, and its aerobic corrosion reaction was slower than that of X65 and X70 pipeline steel. X-ray photoelectron spectroscopy (XPS) results show that the three pipeline steels have the same corrosion mechanism, and all of them form Fe2O3, FeOOH, FeCO3, and FeS. The corrosion process is similar but the speed is different. This is attributed to the more corrosion-resistant trace elements in the X80 pipeline steel composition and the structure more compact. The application of high strength API 5L X80 steel in the product oil pipeline is still in its infancy, and it will be more practical to accelerate the development of API 5L X80 steel to make it more applicable to the construction of product oil pipelines.
... To investigate the electrochemical interaction and morphological arrangements of BSA protein on the Ti6Al4V alloy surface, 1 g L − 1 of BSA protein (lyophilised powder; ≥ 96% agarose gel electrophoresis, Sigma-Aldrich) was dissolved in the abovementioned solutions and the pH was adjusted to approximately 7.4. 100 μM H 2 O 2 (PanReac Applichem, 30% w/v) was also added to some solutions to simulate inflammation conditions [13] . ...
Article
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Protein adsorption and its conformational arrangements on the surface of metallic biomaterials directly influence the biocompatibility and the degradation process during the implant lifetime. However, the presence of various species such as phosphates, calcium and hydrogen peroxide (H2O2) in the human body not only control the electrochemical interactions on the biomaterial surface but could also modify the protein adsorption process and its impact on the metal degradation. To this aim bovine serum albumin (BSA) protein adsorption, morphology, surface potential and its impact on the corrosion resistance of a Ti6Al4V alloy was investigated in different solutions, including a sodium chloride (NaCl), a phosphate-buffered saline (PBS) and Hank's physiological solutions. The results indicated that the alloy in PBS solution was more resistant to corrosion than that in Hanks’ or NaCl solutions. Mott–Schottky analysis demonstrated that all solutions containing BSA and H2O2 had the highest donor charge carrier. Scanning electron microscopy (SEM) and surface potential images indicated that by changing the physiological solutions from NaCl to PBS and then to Hanks’, the morphology of adsorbed BSA protein changed from a globular or unfolded shape to a large micronetwork and then to a fine micro-nanonetwork, accompanied by a gradual increase in the surface potential. Moreover, it was figured out that the BSA protein/substrate interface and the top surface of the BSA protein were susceptible to corrosion initiation owing to the different surface potentials and thus are preferable sites for the adsorption of corrosive counterions, e.g., Cl⁻.
... (i) Inappropriate biocompatibility; releasing metallic ions which are toxic to living cells and tissue. This is the case for NiTi, Ti6Al4V and stainless steel in which release of Ni, Al, V, Mo, and Cr ions can cause a variety of diseases from cancer to Alzheimer's disease and bronchitis [7][8][9][10][11]. (ii) Insufficient bioactivity; in which the implanted material may be unable to stimulate bone formation and healing, degrading the implantation process. ...
Article
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Hydroxyapatite has become an important coating material for bioimplants, following the introduction of synthetic HAp in the 1950s. The HAp coatings require controlled surface roughness/porosity, adequate corrosion resistance and need to show favorable tribological behavior. The deposition rate must be sufficiently fast and the coating technique needs to be applied at different scales on substrates having a diverse structure, composition, size, and shape. A detailed overview of dry and wet coating methods is given. The benefits of electrodeposition include controlled thickness and morphology, ability to coat a wide range of component size/shape and ease of industrial processing. Pulsed current and potential techniques have provided denser and more uniform coatings on different metallic materials/implants. The mechanism of HAp electrodeposition is considered and the effect of operational variables on deposit properties is highlighted. The most recent progress in the field is critically reviewed. Developments in mineral substituted and included particle, composite HAp coatings, including those reinforced by metallic, ceramic and polymeric particles; carbon nanotubes, modified graphenes, chitosan, and heparin, are considered in detail. Technical challenges which deserve further research are identified and a forward look in the field of the electrodeposited HAp coatings is taken.
... These advantages make iron-based materials a potentially exceptional source of biocompatible metallic materials for the medical field (Jin et al., 2016). Addition of Ni to several metals has created the most promising materials for different applications (Xiong et al., 2018;Xu et al., 2018;Negem et al., 2019;Negem and Nady, 2017;Nady and Negem, 2018;Nady and Negem, 2016;Nady and Negem, 2017;Badawy et al., 2014;El-Feky et al., 2013;Negem et al., 2020). The Fe-Cr-Ni stainless steel alloys have become one of the most used materials in the medical field because of its low corrosion rate, excellent toughness and mechanical beneficial properties (Jin et al., 2016). ...
Article
Purpose – The commercial stainless steels have been used extensively in the biomedicine application and their electrochemical behaviour in the simulated body fluid (SBF) are not uncovered obviously. In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys (x = 4, 8, 10 and 14) has been studied. This study aims to evaluate the rate of corrosion and corrosion resistance of some Fe–Cr–Ni alloys in SBF at 37°C. Design/methodology/approach – In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys has been studied using open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization in the SBF at 37°C and pH 7.4 for a week. Also, the surface morphology of the four alloys was investigated using scanning electron microscopy, elemental composition was obtained via energy dispersive spectroscopy and the crystal lattice structure of Fe–17Cr–xNi alloys was obtained using X-ray diffraction technique. The chemical structure of the protective oxide film has been examined by X-ray photoelectron spectroscopy (XPS) and metals ions released into the solution have been detected after different immersion time using atomic absorption spectroscopy. Findings – The results revealed that the increase of the Ni content leads to the formation of the stable protective film on the alloys such as the Fe–17Cr–10Ni and Fe–17Cr–14Ni alloys which possess solid solution properties. The Fe–17Cr–14Ni alloy displayed highest resistance of corrosion, notable resistance for localized corrosion and the low corrosion rate in SBF because of the formation of a homogenously protective oxide film on the surface. The XPS analysis showed that the elemental Fe, Cr and Ni react with the electrolyte medium and the passive film is mainly composed of Cr2O3 with some amounts of Fe(II) hydroxide at pH 7.4. Originality/value – This work includes important investigation to use commercial stainless steel alloys for biomedical application.
... 9 Stainless steel and titanium are among the most used metals, although there have been cases of infection as well reports of little mechanical integration at the time of implantation. 10 Ceramics are considered osteoconductive materials due to the calcium phosphates they contain, and have been shown to promote new bone tissue formation. 11 Hydroxyapatite (HA) has been extensively investigated and defined as potentially osteoconductive and has chemical similarity with bone mineral. ...
Article
Composite biomaterials are solids that contain two or more different materials, combining the properties of their components to restore or improve the function of tissues. In this study, we report the generation of electrospun matrices with osteoconductive properties and porosity using the combination of a biodegradable polyester, polylactic acid (PLA), and hydroxyapatite (HA). Additionally, we report the effects of modifying these matrices through plasma polymerization of pyrrole on the growth and osteogenic differentiation of rabbit bone marrow stem cells. Cells were isolated, seeded and cultured on biomaterials for periods between 7 and 28 days. The matrices we obtained were formed by nano and microfibers containing up to 35.7 wt% HA, presenting a variety of apparent pore sizes to allow for the passage of nutrients to bone cells. Scanning electron microscopy showed that the fibers were coated with polypyrrole doped with iodine, and MTT assay demonstrated this increased cell proliferation and significantly improved cell viability due to the adhesive properties of the polymer. Our results show that PLA/HA/Pyrrole/Iodine matrices are favorable for bone tissue engineering.
... The equivalent circuit applied to fit EIS plots was a classical Randles circuit with a CPE to substitute pure capacitance, because a non-homogeneous surface was considered. 35 It is observed that R ct increased slowly with time, and then decreased at around 8400 s. However, the corresponding current vs. time plot in Figure 10b shows that current started to increase after 9000 s, and there is no noticeable change in current at 8400 s. ...
... Increasing concern regarding the consequences of metal release from biomedical implants has stimulated efforts to better understand the conditions under which corrosion occurs, and the nature of the corrosion products that are released Morrell et al., 2019;. Oxidation-resisting steel, Co-Cr and Ti alloys are the most common biomedical implant metals in use today (Sullivan and Topoleski, 2015;Harun et al., 2017;Xu et al., 2018;. Of these, Ti in its commercially pure and alloyed forms is mostly used for "cementless" implants because of titanium's ability to "osseointegrate" with bone, provide adequate mechanical properties, and exhibit resistance to corrosion under normal physiological conditions (Paka and Pokrowiecki, 2018;Kang and Yang, 2019;Rabadia et al., 2019;Zhang and Chen, 2019;. ...
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Frontiers e-book, comprising all the articles featured in the Research Topic "Advances in Materials Toward Anti-Corrosion and Anti-Biofoulings". Alternatively, you can also access the e-book via the Research Topic homepage (https://www.frontiersin.org/research-topics/24136/advances-in-materials-toward-anti-corrosion-and-anti-biofoulings), where all articles are also individually available.
... Об участии пероксида водорода в коррозии металлов. В ряде литературных источников рассматривается вопрос о влиянии пероксида водорода на коррозию металлов и о его участии в инициировании и стимулировании коррозии металлов [55,56]. ...
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Изучена биокоррозия дюралюминия марки Д16Т и предложен механизм, согласно которому инициаторами начального коррозионного повреждения являются активные формы кислорода (АФК), продуцируемые микромицетами. Сделано предположение об участии перекиси водорода в микологической коррозии сплава Д16Т, образующейся как при жизнедеятельности микромицетов, так и при активации кислорода нульвалентным алюминием (ЗВАл). Предложены механизмы межкристаллитной, питтинговой и питтинговой коррозии дюралюминия под действием микроскопических грибов. Цель: определение основного биологического фактора, инициирующего биокоррозию сплава Д16Т; Объектом исследования был алюминиевый сплав Д16Т по ГОСТ 4784–2019 после закалки и естественного старения, который широко применяется для изготовления силовых элементов конструкций и оборудования топливных систем самолетов, автомобилей. кузовов, деталей различных машин и агрегатов, работающих при низких температурах, в пищевой и фармацевтической промышленности. С помощью сканирующего электронного микроскопа исследованы стадии инициирования и развития биокоррозии сплава Д16Т под влиянием консорциума форм. Исследован фазовый состав продуктов коррозии Д16Т. В процессе жизнедеятельности микроскопических грибов образуются активные формы кислорода, инициирующие биокоррозию сплава Д16Т. Начальная стадия биокоррозии обусловлена гидролизом защитной пассивной алюминиевой пленки. На стадии интенсивной биокоррозии образуются кислородсодержащие соединения алюминия в виде водонасыщенного геля. Далее по мере накопления этого продукта коррозии снижается его водопроницаемость. Гель подвергается «старению» и превращается в кристаллические продукты. Конидии и гифы микроскопических грибов прилипают, механически закрепляются на поверхности металла и проникают в поверхностные слои и вглубь металла, вызывая его коррозионное разрушение в виде язв, язв и полостей. Это возможно, что инициирование биокоррозии металлов является следствием гиперпродукции активных форм кислорода клетками микромицетов в результате окислительного стресса. Это может быть их защитной стратегией, направленной на уничтожение ксенобиотического материала. Развитие межкристаллитной и питтинговой коррозии сплава Д16Т под действием микромицетов происходит в местах контакта с экссудатом, который за счет каскада реакций с участием АФК локально обогащен гидроксид-ионами. Зарождение и развитие питтинга на поверхности дюралюминия происходит в дефектах пассивной оксидной пленки вследствие вытеснения кислородсодержащих поверхностных соединений алюминия и их взаимодействия с коррозионно-активными анионами ОН– и АФК. Перекись водорода, как промежуточный продукт метаболизма микромицетов, на поверхности сплава Д16Т может участвовать в фентоновском процессе или гетерогенно разлагаться, также провоцируя развитие биокоррозии алюминия.
... The narrow scan spectrum of Cr 2p has been deconvoluted to 2 major peaks centred at 576 eV and 586 eV corresponding to Cr 2p 3/2 and Cr 2p 1/2 , respectively. The curve fittings of the Cr 2p 3/2 yield peaks at B.E.s of 573.5, 575.5, 576.8 and 578.0 eV which were attributed to the presence of metallic Cr, Cr 2 O 3 , CrOOH and CrO 3 respectively [68]. The Cr 2p 1/2 component of the spectra was further deconvoluted to peaks at B.E.s of 585.8 eV, 587.2 eV which signifies the presence of Cr 2 O 3 and CrOOH [69]. ...
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The present research is aimed at developing a more economic and ecological way to improve the biocompatibility of medical-grade stainless steel. In order to accomplish the purpose, the 316L stainless steel has been functionalized by depositing self-assembled monolayers (SAMs) of cost-effective Cobalt-based metallosurfactants (CoMS) complex. The fabrication of well-defined SAMs on the surfaces was characterised using FTIR-ATR, spectroscopic ellipsometry and water contact angle measurements. The corrosion stability of functionalized surfaces in simulated body fluid was accessed by various electrochemical and spectroscopic techniques like cyclic potentiodynamic polarisation (CPP), chronoamperometry, electrochemical impedance spectroscopy, FE-SEM, XPS and ICP-MS studies. The metallosurfactant SAMs provided superior corrosion protection and also coerced the SS surface into antibacterial against Gram-negative E. coli bacteria. The cytotoxicity of the SAMs against mouse embryonic fibroblast cell line (NIH-3T3) was assessed by MTT and fluorescent assays. The experimental results reveals that the metallosurfactant SAMs are multifunctional i.e., they enhanced the anticorrosive and anti-bacterial properties of the SS 316L without compromising the cytocompatibility of the surface which make them promising candidates for biomedical applications.
... H 2 O 2 tends to weaken the corrosion resistance of 316L steel [9]. This is related to an increase in the release of Ni ions [10], which is due to the increased reactions between metal ions and strong oxidant H 2 O 2 [11,12]. ...
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The present study investigates the electrochemical corrosion response and tribo-behavior of 304L and 316L stainless steel welded by gas metal arc welding (GMAW), which offered a high deposition rate. During this research, the metallurgically prepared welded samples were subjected to a tribological test and a corrosion test. The wear results were favorable for 316L steel, and it showed a lower coefficient of friction than the 304L specimen. These samples also underwent characterization studies, such as X-ray diffractometry (XRD) and scanning electron microscopy (SEM), to identify the different phases obtained on the cooling of the weld pool. Finally, both specimens were compared against their mechanical properties. Owing to the above properties, the 316L sample showed lasting durability, as compared to the 304L steel. The primary compositional difference is the higher presence of molybdenum and chromium in the 316L steel, compared to the 304L stainless steel.
... Results in this study demonstrate that Ti30Nb3Cu alloy exhibits the best anti-corrosion properties and significantly good anti-bacterial effect on S. aureus, which promising j o u r n a l o f m a t e r i a l s r e s e a r c h a n d t e c h n o l o g y 2 0 2 2 ; 1 8 : 5 2 1 2 e5 2 2 5 application as an implant material. However, biological condition is very a complex system, including different types of organic or inorganic species and living cells [80,81]. Cucontaining metal alloys have been reported to improve osteogenesis, although the detailed mechanisms have not been completely elucidated in previous research. ...
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Novel Ti-xNb-yCu alloys containing various Cu and Nb concentrations have been developed through heat treatment and rapid quenching. The effects of Cu and Nb content on microstructure, corrosion properties and bacterial inhibitory ability of the novel alloys have been systematically investigated with various characterisation methods. Results revealed that Ti3Cu alloy showed a typical eutectoid structure (α-Ti and Ti2Cu), Ti10Nb3Cu alloy exhibited three-phase coexistence microstructure (α+β+Ti2Cu), Ti30Nb alloy comprised of α+β phases, and Ti30Nb5Cu and Ti30Nb3Cu alloys comprised of single β phase. The corrosion behaviour of novel Ti-xNb-yCu alloys were studied in details using electrochemical measurements and immersion testing. It has been found that corrosion resistance of novel Ti-xNb-yCu alloys was improved with increasing Nb content, while the addition of Cu exhibited opposite trend on corrosion resistance. Higher Cu content (5%) in Ti30Nb alloy decreased its corrosion resistance while lower Cu content (3%) improved its corrosion resistance, probably due to the single-phase transition and less Cu-containing precipitates on the grain boundary of Ti30Nb3Cu. Besides, Cu-containing Ti alloys exhibited significantly better bacterial inhibitory properties. This study suggests that, Ti30Nb3Cu alloy with high corrosion resistance and excellent bacterial inhibitory property is promising for biomedical implant applications.
... 316 L SS is mainly composed of Cr, Ni, V, and Mo elements. These elements can cause serious problems once released in the human body due to the corrosive nature of body fluid [17][18][19][20]. ...
Article
316L stainless steel (316L SS) is a class of alloy materials enabling good corrosion performance, noticeable biocompatibility, high mechanical properties, and fulfills the economic aspects. While the biomedical applications of 316L SS are under severe development, some technical hurdles, e.g., low bioactivity are remained to bypass. In this work, a series of the polymer-ceramic layered hybrid systems containing polypyrrole (PPY)-hydroxyapatite (HAp) was electrodeposited on 316L SS after modifying the electrolyte and electrodeposition parameters. Morphological aspects along with chemical and phase structure of the films were investigated by scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), and X-ray diffraction (XRD), respectively. The adhesion strength, corrosion resistance, and bioactivity of the electrodeposited systems were analyzed using tensile test, potentiodynamic polarization, and in vitro assay in simulated body fluid (SBF), respectively. The results illustrated a ≈20% increment in adhesion strength and a ≈60% decrement in corrosion current density of four-layered coating compared to HAp single layer. The bilayered and four-layered coatings stimulate the formation of a compact apatite layer upon immersion assay as a marker of appropriate bioactivity. It is envisaged that the proposed strategy to fabricate a layered hybrid coating system creates new opportunities in the biomedical applications of 316L SS.
Article
Investigations of in vivo corrosion behaviours of Ti-based orthopaedic implants are required for their clinical applications. In this work, C10H12CuN2Na2O8 (Na2Cu-EDTA) has been applied to fabricate a Cu-rich TiO2 ceramic layer on Ti substrate via micro-arc oxidation (MAO). The incorporation of Cu reduces the thickness and porosity of the resultant coating, which also affects its biological properties. With the addition of H2O2 and/or albumin in NaCl solution to simulate the peri-implant conditions, Cu-rich TiO2 ceramic layer displays a desirable chemical stability in simulated human environments whereas the synergistic effect of albumin and H2O2 dramatically affects the electrochemical responses of bare Ti and Cu-free TiO2 layer. Our present work illustrates the influence of in vivo chemical conditions on the corrosion properties of micro-arc oxidized titanium, which provides valuable guidance for its clinical application.
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The role of proteins on the corrosion of selective laser beam melted and a conventional processed cold-rolled FeMn alloy as well as hot-rolled pure iron was investigated in modified simulated body fluid (m-SBF). The corrosion behavior of Fe-alloys was analyzed by electrochemical impedance spectroscopy, atomic force microscopy as well as infrared and Raman spectroscopy. The comparative analysis of these alloys allowed for a differentiation in effects of chemical composition and microstructure. Related corrosion kinetics could be clearly correlated with film formation in m-SBF electrolytes in the presence and absence of lysozyme and bovine serum albumin.
Chapter
Tooth tissue engineering through advancements in cell biology and bioengineering has proceeded toward regeneration of entire tooth or individual and surrounding components of tooth. Tooth regenerative therapy is a novel therapeutic concept directing toward restoration of physiological function of tooth such as mastication, periodontal ligament function, and response to noxious stimuli. Tooth regeneration is achieved through two distinctive approaches such as cell transplantation and cell homing. Cell-based strategies are a promising potential for regenerating the whole tooth structure in rodents but rendering obstacles in therapeutics. Cell homing is an under-recognized alternative approach to cell delivery-based tooth regeneration. This approach provides tangible pathway toward clinical translation. Scaffold-based or scaffold-free tissue engineering is considered for tooth regeneration. Scaffold-based approach uses scaffolds planted with cells either in vitro or by cell homing. Scaffold-free approach directly induces development of embryonic tooth formation by appropriate signals to produce tooth structure which mimics natural teeth in morphology and size. The combination of biomaterials and human tooth‐associated with stem cell populations isolated from dental pulp and periodontal ligament tissues shows promising approach to regenerate human dental tissues. Scaffolds provide biophysical support for cell recruitment, adhesion, proliferation, differentiation, and metabolism. The designed scaffolds should be biocompatible, non-toxic, and promote regeneration of single or multiple dental tissues. Different types of biomaterials for constructing scaffolds are available that can regenerate tooth components which successfully improves the treatment outcome.
Chapter
In the current chapter, critical review on the development and surface modification of stainless steel (SS)-based implants for biomedical applications has been presented. In the first phase, the significance and importance of SS-based biomaterial are presented. The technique for the development of porous and solid biomedical implants was discussed in details for their successful applications. The application of powder metallurgy for the development of porous implants was found suitable. The powder metallurgy (PM) route has been most widely used for the development of porous scaffolds, because in this process pore characteristics are easy to control and capability to generate very close to the final shape of the product. The fabrication of porous structure in PM route consists of the first alloying of removable temporary space holders with powder particles then pressureless sintering. In the second phase, a critical review on the in vitro bioactivity analysis of SS-based biomaterial has been presented. The chapter also presents the future scope for the development and surface modification of biomedical implants.
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Magnesium (Mg) based material systems offer great potential for healing bone fracture and defects, in terms of reduced stress shielding effect and non-toxicity, due to their biodegradability and biocompatibility. However, issue with controlling degradation rate of Mg in an intraosseous (Occurring within bone) environment has impeded their application in orthopaedics. As a solution to this problem, Mg can be combined with other corrosion resistant and bioactive material to form composite. Hydroxyapatite (HA) is an attractive bioceramic for implants due to its similar chemical composition to the apatite found in bone. Thus, incorporation of HA in Mg assists in enhancing multiple engineering properties that are critical for its widespread use in orthopaedic application. Tremendous improvement in the mechanical and degradation properties of HA reinforced Mg composite, along with their impressive biocompatibility, has led to further interest in research, which has resulted in some clinical trials of Mg-HA based composites, as well. This review article summarises researches, carried out till date on Mg-HA based composite, with a special focus on significant role of HA in tuning the degradation and mechanical behaviour of Mg based materials. The detailed summary on biocompatibility of Mg-HA based composites has also been covered. A comprehensive understanding on biocompatibility and degradation behaviour of Mg-HA system is needed to assess the potential of these composites in orthopaedic application. However, such review is missing in available literatures. On the basis of current studies available on Mg-HA based composites for orthopaedic application, guidelines for future application in clinical trials have also been framed and presented in this review article.
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The corrosion of Co–28Cr–6Mo and Co–35Ni–20Cr–10Mo, as biomedical alloys, has been investigated for effects of typical species (albumin and H2O2) in physiological saline, with their coexistence explored for the first time. Electrochemical and long term immersion tests were carried out. It was found that Co alloys were not sensitive to the presence of albumin alone, which slightly promoted anodic dissolution of Co–35Ni–20Cr–10Mo without noticeably affecting Co–28Cr–6Mo and facilitated oxide film dissolution on both alloys. H2O2 led to a clear drop in corrosion resistance, favouring metal release and surface oxide formation and inducing much thicker but less compact oxide films for both alloys. The coexistence of both species resulted in the worst corrosion resistance and most metal release, while the amount and composition of surface oxide remained at a similar level as in the absence of both. The effect of H2O2 inducing low compactness of surface oxides should prevail on deciding the poor corrosion protection ability of passive film, while albumin simultaneously promoted dissolution or inhibited formation of oxides due to H2O2. Corrosion resistance was consistently lower for Co–35Ni–20Cr–10Mo under each condition, the only alloy where the synergistic effect of both species was clearly demonstrated. This work suggests that the complexity of the environment must be considered for corrosion resistance evaluation of biomedical alloys.
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Repair, reconstruction, and replacement of congenital malformations, either in case of exogenous or iatrogenic tissue and organ defects, requires utilization of a large number of personalized biomaterials. In recent decades, the improvement of people’s quality of life and the prolongation of life expectancy have promoted the development of medical and material science. In addition to the traditionally used stainless steel, other materials such as cobalt–chromium alloy, pure titanium, titanium alloy, and the newly alloy materials continue to emerge, such as tantalum-based alloy materials which have been used in clinic, especially the application of porous tantalum trabecular metal in orthopedics. This paper which has provided good preliminary works for the development of tantalum biomaterials with more advantages in the future such as tantalum dental implants summarizes in detail the progress of tantalum materials in physicochemical properties and biocompatibility in recent years. From the comparison of surface passivation films of different metals in different environments, the electrochemical corrosion behavior of tantalum, the release of different metal ions and the damage to cells, it is concluded that tantalum has excellent corrosion resistance. Besides, the excellent biocompatibility of tantalum metals concluded by cytology, molecular biology, protein adsorption experiment, and hematology experiment, as well as regular follow-up observation of patients with porous tantalum trabecular metal in clinic. The excellent corrosion resistance and biocompatibility of the tantalum metal have a very wide prospect in clinical application.
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Crevice corrosion of high-speed rail steel U75V was studied with varying gap size by using self-designed device. Increasing gap size inhibited exterior cathodic reduction reaction of oxygen, inducing decrease of potential difference between interior and exterior. Gap size decrease after increase induced increase of potential difference after decrease, not completely reversible because rust kept expanding, acting as weaker depolarizer than oxygen. Anodic dissolution of interior was under ohmic-control, fastest near crevice mouth and slowest near but not at deepest site. Corrosion initiation was observed, closely related to pearlite nodules with larger interlamellar spacing and different lamellar directions, inducing deep attack.
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In the present study, the distribution of Ag in the coating formed on Mg-Ag alloy by plasma electrolytic oxidation (PEO) and its ionic release kinetics when exposed to a 0.9 wt.% NaCl solution at 37 °C have been investigated. Both metallic Ag and Ag oxide particles with ∼5 to ∼40 nm in diameters were observed in the PEO coating. Further, an Ag-enriched layer of ∼20 nm in thickness at the substrate/coating interface was also observed. The PEO coating on the Mg-Ag alloy not only increases its corrosion resistance with the corrosion current density decreasing by up to 3 orders of magnitude from 8.04 × 10⁻³ to 4.03 × 10⁻⁶ A/cm², but also controls the release of Ag⁺ to the level that is sufficient for anti-infective efficacy without causing cytotoxicity to mammal cells.
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The pitting corrosion of SS-316L in human body fluid leads the metallic prosthesis to lose its strength along with severe health consequences such as metallosis condition. Hence, an effective alternative for enhancing the biocompatibility of the SS-316L implant is the electrochemical deposition of a bioinert hydroxyapatite (HAP) coating over the metallic surface. A dense HAP coating was successfully developed on SS-316 L in a supersaturated electrolyte containing Ca+2 and PO43− ions. Electrochemical essays and SEM morphological observation showed the SS-316 L pitting corrosion caused by chloride containing body fluid. The effects of the electrodeposition time and the temperature of the supersaturated electrolyte were assessed using current–time transients, scanning electron microscopy, Energy-dispersive X-ray spectroscopy, Raman and X-ray diffraction analyses. The increase in the temperature promotes the HAP coating formation and accelerates the particles nucleation. An instantaneous HAP growth with no evidence for intermediate phase of HAP formation has been noticed.
Article
Background: Telescopic rods in the management of osteogenesis imperfecta fail frequently. This could be attributed to technical errors, rod design, and rod structure. We aimed to analyze the mechanical properties and tribology of explanted male and female components to identify effects of in vivo telescoping that may relate to observed patterns of successful telescoping or failure. Methods: Recruitment took place at 3 of the 4 English centers for osteogenesis imperfecta. Twenty-five rods explanted for growth or failure during revision to a new rod were analyzed in terms of clinical indication and prerevision imaging to identify if there was a technical mode of failure. Laboratory analysis was performed using optical and scanning electrical microscopy, radiograph diffraction analysis, hardness test, bending test, and energy-dispersive x-ray spectroscopy. Results: All implants tested were of high-grade stainless steel. Female components had inferior strength [mean Vickers hardness property (HV0.3) at 0.3 to 313 kg] in comparison to male components (HV0.3 406) due to different techniques of manufacture. Female rods also had a higher wear coefficient (7.89×10-12 m3/N/m3) than the male rods (6.46×10-12 m3/N/m3). Abrasive wear, shear deformation, scratches, and wear debris were identified in all rods. Male and female components displayed corrosion contributing to adhesive wear. Intraoperatively cut rods, particularly the female components, had irregular ends leading to more wear. Conclusions: Current manufacturing techniques result in inferior material strength in female components compared with males, which combined with wear patterns is likely to lead to implant failure. Intraoperative cutting of rods may increase risk of failure due to wear. Considering techniques to improve strength as well as design in new implants may lead to better outcomes. Levels of evidence: Level IV-cross-sectional study.
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3D-printing is an emerging technology that challenged wrought counterparts by one-step manufacturing for complicated biological devices. However, the material properties and surface features due to manufacturing parameters play an important role on the corrosion behaviour and influence the toxicity of the material as an implant. In this paper, the improvement of pitting potential was observed by electrochemical experiments as the result of grain refinement of DMLS 316L at 200W laser power. The ICP results verified the supressed release of toxic cations after the formation of the passive film with enhanced characteristics. However, the pores from DMLS 316L have the potential to develop into pits when polarised above pitting potential, promoting the risk of using 3D-printed 316L as implant materials.
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The corrosion of 316L stainless steel in simulated body fluid mixed with antiplatelet drugs was electrochemically investigated and characterized using near-edge X-ray absorption fine structure and X-ray photoelectron spectroscopies and metal-free ion chromatography associated with inductively coupled plasma–mass spectrometry. Commercial antiplatelet drug ions Ca²⁺, PO4³⁻, SO4²⁻, K⁺, Mg²⁺, and Cl⁻ produced various passive films on the 316L surface. Hydroxyapatite combined with the highest inhibitory-layer Cr(III), Fe(II), and O²⁻ concentrations provided the most efficient corrosion prevention. Results suggest that antiplatelet drugs are vital for anticoagulation and for preventing corrosion of devices implanted in patients during percutaneous coronary intervention.
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Despite advances in stent technology for vascular interventions, in-stent restenosis (ISR) remains a main complication. The corrosion of cobalt-chromium (CoCr) alloy coronary stents has been identified to be associated with ISR, whereas its role in ISR has not been elucidated. In the current work, CoCr nanoparticles, simulated corrosion products of CoCr alloy, were used to investigate their effect on the endothelial cells. It has been demonstrated that the cell viability declines and the cell membrane is damaged, indicating the cytotoxicity of CoCr nanoparticles. The expression of GRP78, CHOP, and cleaved-caspase12 proteins has increased when exposed to CoCr nanoparticles, suggesting that CoCr nanoparticles induced cell apoptosis through endoplasmic reticulum (ER) stress-mediated apoptotic pathway. An increased release of adhesion and inflammatory mediators was also induced by CoCr nanoparticles, including ICAM-1, VCAM-1, IL-1β, IL-6, and TNF-α. Our results demonstrated that CoCr nanoparticles could trigger apoptosis, adhesion, and inflammation. These findings indicated potential damaging effects of CoCr nanoparticles on the vascular endothelium, which suggested corrosion of CoCr alloy may promote the progression and development of ISR.
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The study concerning the effects of inflammation on the corrosion behaviour of biodegradable Zn was carried out for the first time. Simulated inflammatory solutions containing H2O2 or Fenton’s reagent were prepared for electrochemical measurements and immersion tests. It turned out that H2O2 can significantly influence the mechanism underpinning Zn degradation, the degree of which varied with H2O2 concentration, and acted differently in PBS and Hank’s solution. Meanwhile, Fenton reactions also exerted a noticeable impact on Zn corrosion and the corrosion product formation. A proposal is thus put forward that degradation as biological consequences should be considered in evaluating biodegradable Zn.
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Adhered oysters can cause complex corrosion of fouled steel structures, with localized crevice corrosion being the most severe. A crevice corrosion model of steel caused by oysters is proposed, showing that oyster secretions can penetrate into the oyster/steel interface and act as a stabilizer of the rust layer, enabling tight attachment and thereby slowing the metal corrosion rate. In contrast, oxygen concentration cells, enriched Cl⁻, anaerobic bacteria, the presence of organic free radicals and oxidative cross-linking during the curing process of oyster secretions act as localized corrosion accelerators facilitating the crevice corrosion process in the oyster/steel gap.
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H2O2 usually develops after implanting an implant of biomedical material in human body. Our study showed that H2O2 has dual effects on degradation behaviour of biomedical material depending on its concentration. As for a SLMed CoCrMo alloy, a critical concentration of H2O2 exists, below which the corrosion potential shifts positively as the concentration increases, facilitating the passive film formation; and above which, the film becomes less protective due to the change in composition of the film. The corrosion resistance of XOZ plane of the alloy is better than that of XOY plane due to less grain boundaries and secondary precipitates.
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Titanium and alloys thereof are widely utilized for biomedical applications in the fields of orthopedics and dentistry. The corrosion resistance and perceived biocompatibility of such materials are essentially related to the presence of a thin passive oxide layer on the surface. However, during inflammation phases, the immune system and its leukocytic cells generate highly aggressive molecules, such as hydrogen peroxide and radicals, that can significantly alter the passive film resulting in the degradation of the titanium implants. In combination with mechanical factors, this can lead to the release of metal ions, nanoparticles or microscaled debris in the surrounding tissues (which may sustain chronic inflammation), bring about relevant health issues and contribute to implant loss or failure. After briefly presenting the context of inflammation, this review article analyses the state-of-the-art knowledge of the in vitro corrosion of titanium, titanium alloys and coated titanium by reactive oxygen species and by living cells with an emphasis on electrochemical and microstructural aspects. Statement of Significance Inflammation involves the production of reactive oxygen species that are known to alter the passive layer protecting titanium implants against the aggressive environment of the human body. Inflammatory processes therefore contribute to the deterioration of biomedical devices. Although review articles on biomaterials for implant applications are regularly published in the literature, none has ever focused specifically on the topic of inflammation. After briefly recalling the clinical context, this review analyses the in vitro studies on titanium corrosion under simulated inflammation conditions from the pioneer works of the 80s and the 90s till the most recent investigations. It reports about the status of this research area for a multidisciplinary readership covering the fields of materials science, corrosion and implantology.
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The application of MgAg alloy for the fabrication of orthopedic implant requires its enhanced corrosion resistance, desired biocompatibility and bactericidal capability without cytotoxicity. Herein, to achieve those purposes, a novel plasma electrolytic oxidation (PEO) treatment was proposed. The PEO coating with a bimodal pore size distribution could form on MgAg alloy surface to enhance its corrosion resistance. Further, the incorporation of magnesium phosphate in the PEO coating may also benefit its biocompatibility. Finally, Ag within the alloy could be gradually oxidized to form incorporated Ag⁺ and nano-sized Ag2O particles in the coating, which potentially optimize the ionic release kinetics of Ag for a desired antibacterial capability without cytotoxicity. Hence, the present work offers a novel PEO method to improve the corrosion resistance and biological response of MgAg alloy, which enlightens the application of antibacterial Mg alloy in the field of biomedical devices.
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In this paper, the passivation and electrochemical behavior of 316L stainless steel in chlorinated simulated concrete pore solutions at different pH was evaluated by potentiodynamic measurements, electrochemical impedance spectroscopy. The composition of the passive film and surface morphology were investigated by X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and scanning electron microscopy, respectively. The results reveal that metastable pitting susceptibility, stable pitting corrosion, and composition of the passive film are influenced by pH value. After long time immersion, a bilayer structure passive film can be formed in this environment. The appearance of molybdates on the outermost surface layer, further enhancing the stability of the passive film. Moreover, the good pitting corrosion resistance of 316L stainless steel in simulated concrete pore solution without carbonated is mainly due to the presence of high Cr/Fe ratio and molybdates ions within the passive film.
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Stainless steel alloys, including 316L, find use in orthopaedics, commonly as fracture fixation devices. Invasive procedures involved in the placement of these devices will provoke a local inflammatory response that produces hydrogen peroxide (H2O2) and an acidic environment surrounding the implant. This study assessed the influence of a simulated inflammatory response on the corrosion of 316L stainless steel. Samples were immersed in an electrolyte representing either normal or inflammatory physiological conditions. After 24 h of exposure, electrochemical impedance spectroscopy (EIS) and inductively coupled plasma mass spectroscopy (ICPMS) were used to evaluate differences in corrosion behavior and ion release induced by the inflammatory conditions. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) were used to evaluate surface morphology and corrosion products formed on the sample surface. Inflammatory conditions, involving the presence of H2O2 and an acidic pH, significantly alter the corrosion processes of 316L stainless steel, promoting aggressive and localized corrosion. It is demonstrated that particular consideration should be given to 316L stainless steel implants with crevice susceptible areas (ex. screw-head/plate interface), as those areas may have an increased probability of rapid and aggressive corrosion when exposed to inflammatory conditions.
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The synergistic effect of albumin and H2O2 on corrosion of titanium alloy Ti6Al4V in physiological saline was investigated with long-term immersion tests and electrochemical methods. It was found that in the presence of both albumin and H2O2, the rate of metal release in immersion tests was far higher than in the presence of either species alone. Electrochemical polarisation curves and potentiostatic tests showed that H2O2 increased both the rates of the anodic and cathodic reactions, while albumin significantly decreased the rate of the cathodic reaction and slightly decreased the rate of the anodic reaction. The synergistic effect of albumin and H2O2 during immersion tests was attributed to the effect of adsorption of albumin in lowering the rate of the cathodic reaction and thus lowering the open circuit potential into the active region of titanium where complexation by H2O2 increased the corrosion rate. The corrosion attack was found to be greater in the β-phase of the alloy. The findings suggest that current standard tests in physiological or phosphate-buffered saline may underestimate the rate of corrosion in the peri-implant environment, in which albumin is the predominant protein, and reactive oxygen species such as H2O2 can occur as a result of inflammatory reactions in response to surgery, infection, or implant corrosion products. Copyright © 2015. Published by Elsevier Ltd.
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In this study, the effect of human serum albumin (HSA) in a concentration range of 0 to 4 g L-1 in phosphate buffered saline (PBS) on the electrochemical corrosion behavior of AISI 316L, wrought Co-28Cr-6Mo and Ti-6Al-4 V was investigated by advanced electrochemical corrosion experiments such as cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The cyclic voltammetry results showed that the dissolution rate of iron from 316L and cobalt from Co-28Cr-6Mo alloy decreased in the presence of HSA. HSA also increased the oxidation of adsorbed hydrogen on Ti-6Al-4 V alloy by the external donation of hydrogen atoms. These results implied the formation of an adsorbed layer of protein on the oxide layer which was confirmed by the result of the EIS experiments. Furthermore, the increase of HSA concentration increased the surface coverage of HSA. The comparison of the BSA (bovine serum albumin) as an animal serum albumin with HSA showed that the surface coverage and the cathodic inhabitation of BSA were higher than HSA.
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The long-term weight loss, ion release, and surface composition of 316L, Co-28Cr-6Mo and Ti-6Al-4V alloys were investigated in a simulated body environment. The samples were immersed in phosphate-buffered saline (PBS) solutions with various human serum albumin (HSA) concentrations for 8, 14, and 22weeks. The specimens initially lost weight up to 14weeks and then slightly gained weight. The analysis of the released ions was performed by induced coupled plasma-optical emission spectrometer (ICP-OES). The results revealed that the precipitation of the dissolved Fe and Co could cause the weight gain of the 316L and Co-28Cr-6Mo alloys. The surface chemistry of the specimens was determined by X-ray photoelectron spectroscopy (XPS). The XPS analysis of Co-28Cr-6Mo alloy showed that the interaction of Mo with HSA is different from Mo with bovine serum albumin (BSA). This was also observed for Na adsorption into the oxide layer of Ti-6Al-4V alloy in the presence of HSA and BSA.
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The long-term weight loss, ion release and surface composition of AISI 316L, the Co–28Cr–6Mo and Ti–6Al–4V alloys were investigated in phosphate buffered solutions (PBS) with various bovine serum albumin (BSA) concentrations. All the samples lost weight up to 14 weeks and then started to gain weight. This can be explained by precipitation of dissolved ions on the surface after 14 weeks of immersion. The quantities of the dissolved ions were measured in immersed solution for 8, 14 and 22 weeks by induced coupled plasma-optical emission spectrometer (ICP-OES). The amounts of Fe released from 316L, and Co and Mo released from the Co–28Cr–6Mo alloy decreased after 14 weeks of immersion in PBS and BSA solutions. This observation coincides with the weight change of the samples. The oxide layer composition and concentration of the specimens exposed to solutions for 22 weeks were identified by X-ray photoelectron spectroscopy (XPS) analysis. The XPS results revealed that chromium is the main component of the 316L and Co–28Cr–6Mo alloy. The high Cr concentration of the 316L and Co–Cr–Mo oxide layer corresponds with the slow dissolution rate of Cr compared to other alloying elements of the 316L and Co–28Cr–6Mo alloy.
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The precipitation behavior and sensitization resistance of Type 316L(N) stainless steels containing different concentrations of nitrogen have been investigated at the aging condition of 700°C for cold work (CW) levels ranging from 0% (as solution annealed) to 40% reduction in thickness. The precipitation of M23C6 carbide and intermetallic compounds (χ, Laves and σ phase) was accelerated by increasing the CW level. Nitrogen in the deformed alloys retarded the inter- and intra-granular precipitation of the carbides at low and high CW levels respectively, whereas it increased the relative amount of the χ phase. Quantitative assessment of the degree of sensitization (DOS) using the double loop-electrochemical potentiokinetic reactivation (DL-EPR) tests indicated that CW levels up to 20% enhanced sensitization while 40% CW suppressed sensitization for all aging times. The increase in nitrogen content accelerated the sensitization at CW levels below 20%. This might be associated with the homogeneous distribution of dislocations and the lower tendency toward recrystallization exhibited in the alloys having higher nitrogen content.
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Cr–Mn mixed-oxide based catalysts were prepared for the low-temperature selective catalytic reduction of NOx with ammonia in the presence of excess oxygen. It was found that the Cr(0.4)–MnOx showed the highest activity and yielded 98.5% NOx conversion at 120 °C. XRD, TPR and Raman data results suggested that a crystalline phase of CrMn1.5O4 was present in the Cr–MnOx catalysts, which contained the active species. XPS results of fresh, used and regenerated Cr(0.4)–MnOx catalysts illustrated clearly the presence of Mn2+, Mn3+, Mn4+ and Cr2+, Cr3+, Cr5+ oxidation states. Efficient electron transfer between Cr and Mn in the crystal of CrMn1.5O4 was thought to be the reason for the high activity and long lifetime of the Cr(0.4)–MnOx catalyst. In addition, the SCR activity was gradually suppressed in the presence of SO2, while such an effect was shown to be reversible after switching off the SO2 injection.
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The principles of the ESCA and the Auger-techniques are described and a method for quantitative ESCA analysis of passive film is presented. The method is exemplified by an analysis of the passive film formed on stainless steel (20Cr18Ni6MoO.2N) during polarization in 0.1 M HCl + 0.4 M NaCl. The thicknesses of the passive films formed at −100 mV and 500 mV (SCE) are 13 Å and 15.5 Å respectively. The film consists of an inner FeCr oxide phase and an outer monolayer of Cr(OH)3. The average cation content of Cr3+ in the inner oxide is about 50%. Variable angle analysis shows that the Cr3+ content is higher at the metal interface than at the outer interface. Mo6+ is enriched in the outer layer. The content of Mo4+ in the oxide layer decreases with the potential. The Ni2+ content in the passive film is low. Chloride ions are dissolved in the oxide as well as in the hydroxide layer. A stationary state is reached within 2 min.
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XPS studies of solvated metal atom dispersed (SMAD) catalysts coupled with detailed studies of reference compounds of iron metal, FeO, Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, and FeOOH were carried out. It is shown that toluene-solvated iron atoms nucleate at surface OH groups of the Al{sub 2}O{sub 3} catalyst support. The resultant iron oxide surface species served as nucleation sites for deposition of more iron atoms, leading to very small metallic iron clusters/particles. A thin oxide layer was detected on the particle surface that is believed to come from adventitious oxygen.
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MoO3 and Mo samples containing copper were treated with different hydrocarbon/hydrogen gas mixtures. The formation of Mo2C was followed by X-ray photoelectron spectroscopy (XPS). Spectra taken in the Mo 3d, C 1s, O 1s, Cu 2p and Cu KLL regions demonstrated that the treatment with the hydrocarbon/hydrogen gas mixtures led to the formation of Mo2C. From the comparison of the effects of various hydrocarbons on the XP spectra of Mo 3d we can state that the reduction of MoO3 starts at the lowest temperature for C2H6/H2 (600K) followed by CH4/H2 (700K) and C4H10/H2 (723K). Binding energies of Mo 3d5/2 characteristic for Mo2C are measured in the range of 227.7–228.0eV. These values were attained at 900K for CH4/H2, at 800K for C2H6/H2 and at 873K for C4H10/H2. Addition of copper to MoO3 catalyzed its reduction and promoted the carburization process.
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The interaction of oxygen with vapor-deposited Ni on yttria-stabilized ZrO2(100) and the thermal stability of the oxygenated deposit were studied by XPS, UPS and CO TPD experiments, for two different Ni deposits. For 0.4 ML of Ni deposited at 300 K, the Ni2p core level spectra show complete oxidation above 110 L of O2 at 300 K, whereas for 5 ML of Ni deposited at 570 K, the Ni2p and the UP spectra show that oxidation slowly approaches completion above 4500 L of O2 at 420 K. Oxidation extends up to the Ni2+ state and is accompanied by a drastic decrease of CO desorption temperature and desorbed amount. Upon annealing at increasing temperature, oxide decomposition is in both cases already complete at 870 K. At 700 K, the low-coverage Ni deposit has been reduced by more than 70%, whereas the high-coverage deposit by less than 40%. The results are discussed in comparison with the well studied interaction of O2 with Ni monocrystals and a few available reports on the oxidation of Ni clusters on other substrates.
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The effect of ionizing radiation on steel corrosion is an important materials issue in nuclear reactors. In the presence of ionizing radiation water decomposes into both oxidizing and reducing species (e.g., OH, H2O2, O2−) whose net interactions with steels are not fully understood. The effect of radiation on the corrosion kinetics of carbon steel has been studied at pH 10.6 and room temperature, using electrochemical and chemical speciation analyses. The present study investigates the effect of γ-radiation on carbon steel corrosion and compares it with that of chemically added H2O2, which is considered to be the key radiolytically produced oxidant at room temperature. Various oxide films were pre-grown potentiostatically on carbon steel electrodes, and then exposed to either γ-radiation at a dose rate of ∼6.8kGyh−1 or to H2O2 in a concentration range of 10−6 to 10−2M. The corrosion kinetics were studied by monitoring the corrosion potential (ECORR), and periodically performing linear polarization (LP) and electrochemical impedance spectroscopy (EIS) measurements.
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The influence of bovine serum albumin (BSA) on the anodic dissolution of chromium present in UNS S31254 stainless steel (SS) in 0.15molL−1NaCl at 37.0±0.5°C has been studied, using anodic potentiostatic polarization curves and optical emission spectroscopy. Electrochemical results have shown that BSA has little effect on the transpassivation potential (ET) and on the passivation current density values. However on the passivation range, BSA diminishes the intensity of the anodic wave seen at about E=750mV versus SCE attributed to Cr(III)/Cr(VI) oxidation. Optical emission spectroscopy results have shown that BSA prevents the anodic dissolution of chromium to occur and minimizes iron dissolution above the transpassivation potential (E=1160mV versus SCE).
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The effects of the presence of bovine serum on the nucleation of corrosion pits on 316L stainless steel and commercially pure titanium in Ringer’s physiological solution at 37°C are presented. The experiments involved measurement of current transients generated on microelectrodes under potentiostatic control below the pitting potential. Results show that the presence of the organic components of the serum stimulates the nucleation of pits on 316L stainless steel. A similar but smaller effect is shown for commercially pure titanium.
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The corrosion behaviour of AISI 316L, wrought Co–28Cr–6Mo and Ti–6Al–4V was studied in aerated solutions of phosphate buffered saline (PBS) at various concentrations of bovine serum albumin (BSA) at 37 °C. Open circuit potential, potentiodynamic polarization, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) experiments along with X-ray photoelectron spectroscopy (XPS) on Co–28Cr–6Mo oxide layer were conducted to study the interaction of BSA and passive layers and to measure the corrosion rates. Ti–6Al–4V alloy had the lowest corrosion rate and the highest breakdown potential. It was shown that BSA has enhanced the alloy passive film stability at higher concentrations.Highlights► Potentiodynamic polarization, EIS and LPR measurements on AISI 316L, Co–28Cr–6Mo, and Ti–6Al–4V alloys in PBS solutions at various BSA concentrations. ► Corrosion rates calculations by EIS and LPR methods. ► Interaction of BSA with the passive layer of AISI 316L, Co–28Cr–6Mo, and Ti–6Al–4V alloys.
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The adsorption behavior of bovine serum albumin (BSA) on high-purity austenitic low-carbon stainless steel and its effect on the state of the electrode surface have been studied over the temperature range 299−343 K under open-circuit-potential conditions, using electrochemical impedance spectroscopy (EIS). The impedance spectra were interpreted in terms of an equivalent electrical circuit (EEC) based on a possible physical model with the circuit elements representing the electrochemical properties of the investigated system. The adsorption of BSA onto the stainless steel surface resulted in an increased rate of metal dissolution, i.e., corrosion. The plateau values of corrosion rate were achieved after a “threshold” BSA concentration in the bulk solution at all the temperatures studied. The rate of the corrosion process was found to be controlled by both the surface diffusion and charge transfer process. Adsorption of BSA onto the stainless steel surface was described with a Langmuir adsorption isotherm. The thermodynamic data were calculated to give the corrosion activation energy, Gibbs free energy, enthalpy, and entropy of adsorption. The data suggested a very strong adsorption of BSA molecules, accompanied by a charge transfer mechanism involving chemisorption. An adsorption mechanism was proposed involving the interaction of the negatively charged carboxylate groups of the proteins with the stainless steel surface. The EIS technique was shown to be a valuable tool in studying the interfacial behavior of proteins at metal electrode surfaces.
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ESCA, X-ray excited Auger (XAES), and electron excited Auger (EAES) studies were performed on Fe, FeB, and Fe2B. Relative peak areas of the ESCA core levels were used to show that the compositions of the borides' analyzed surfaces were the same as the bulk, i.e., stoichiometric. The absence of binding energy shifts between the iron and boron ESCA core levels compared with the pure elements (iron and β-rhombohedral boron) indicated that no major charge transfer occurred between iron and boron in the borides. This was supported by the XAES, EAES, and plasmon loss spectra. Evidence is given for localized boron bonding in FeB (with covalent bonds between the boron atoms) and isolated boron atoms in Fe2B. The boron-iron bonding in these compounds is metallic. The iron boride valence bands are consistent with the metallic properties, and their increased width over Fe and different fine structure is due to changes in the d-band substructure.
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Studies of the electroreduction of cystine (RSSR) and oxidation of cysteine (RSH) at several pH's at a hanging Hg drop electrode by cyclic voltammetry and at a Hg pool by coulometry are described. The proposed mechanism for RSSR involves reduction of an adsorbed monolayer (maximum coverage of 41 μC cm−2) to form solution phase RSH at the adsorption prewave. A diffusion controlled reduction of RSSR to RSH occurs at more negative potentials. Oxidation of RSH involves formation of an adsorbed organomercury species, e.g., Hg(RS)2 (maximum coverage of 80 μC cm−2), which is reducible back to RSH. At higher RSH concentrations, anodic and cathodic current spikes appear on the cyclic voltammograms which are ascribed to formation of a tight or compact film when monolayer coverage of Hg(RS)2 is attained, corresponding to strong interactions between adsorbed species.
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The influence of surface finishing (polishing and passivation) on the release of Cr, Fe, Ni from the stainless steel 316 implant materials to Hanks solution with or without H2O2 (simulating a body inflammatory response) was investigated. The surfaces were characterized by means of SEM EDXS, XPS and Kelvin Probe measurements before and after exposure to the synthetic body fluids. The total metal ions release rates are more than 10 times higher in the presence of H2O2, independently of the surface finishing. In the absence of H2O2, formation of a surface layer consisting mainly of Ca3(PO4)2 was observed, most likely it was responsible for the observed decrease of the release rates.
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This paper presents a report on the XPS coherent binding energy (BE) data basis for iron and sulfur reference compounds that are representative of oxidation products formed onto the pyrite reactive surface. This work is unique for various reasons: (1) no recent (published after 1980) BE data basis with similar normalization method has been found in the literature; (2) the coupling of data collected from Fe and S photoelectron peaks and from charge transfer satellites of Fe allows for the simultaneous determination of the oxidation state and chemical environment; (3) the depth heterogeneities of samples can be taken into account by comparing the data obtained with Fe2p and Fe3p peaks, whose associated BEs are widely divergent.In the second part of the paper, the data in BEs obtained from reference compounds have been exploited to show the surface species of an oxidized pyrite in a HCO3− medium (10−2 M).
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Metal ion release from metallic materials, e.g. stainless steel, cobalt–chromium alloy, titanium, and titanium alloys, implanted into human body was reviewed in this paper. Surface oxide films on metallic materials play an important role as an inhibitor of ion release and they change with the release in vivo. Low concentration of dissolved oxygen, inorganic ions, proteins, and cells may accelerate the metal ion release. The regeneration time of the surface oxide film after disruption also governs the amount of released ion. In addition, preferential release of specific elements during wear and fretting of metallic materials occurs. The behavior of metal ion release into biofluid is governed by the electrochemical rule. Released metal ions do not always combine with biomolecules to appear toxicity because active ion immediately combine with a water molecule or an anion near the ion to form an oxide, hydroxide, or inorganic salt. Thus, there is only a small chance that the ion will combine with biomolecules to cause cytotoxicity, allergy, and other biological influences.
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Polarised specimens of AISI 304L and 316L stainless steels (SS) were studied using X-ray photoelectron spectroscopy in conjunction with Ar+-ion sputtering. A 5% NaCl test solution was used at room temperature. The polarised passive films formed consist mainly of chromium oxide and hydroxide and a small proportion of iron oxides. The composition of the films depend strongly on the potential. Chloride and molybdenum ions appear when the AISI 316L SS alloy is polarised at a potential close to pitting potential.
Article
Electrodeposition in Cr(VI) and Cr(III) aqueous electrolytes is found to produce, respectively, granular and spherical core-shell nanoparticles on H-terminated Si(100). For the granular nanoparticles obtained by electrodeposition in CrO3 and H2SO4 electrolyte solution, both the morphology and number density remain discernibly similar while the particle size increases with increasing charge transfer. In the CrCl3 electrolyte, evolution of the spherical nanoparticles to homogeneous Cr films without and with atop hexagonal microrods with increasing charge transfer is observed. The viability of producing a homogeneous Cr film on the Si substrate is therefore demonstrated. Both the granular Cr nanoparticles and the Cr film consist of predominantly Cr metallic core and Cr2O3 outer shell covered by surface CrO3, while the novel hexagonal microrods are made up of a metallic Cr core and a CrOOH shell.