Journal of Surface Engineered Materials and Advanced Technology

This paper presents the results of equal channel angular pressing (ECAP) and subsequent heat treatment (HT) as a method to improve the wear resistance of metallic materials in friction sliding. The effect of ECAP and HT on the microstructure and mechanical properties of low carbon steel is investigated in this work. The mechanisms of wear resistance of steel with ultrafine and nanostructures produced by equal-channel angular pressing is analyzed. The results show that ECAP at room temperature and annealing at 350&degC and 450&degC can be used as a technology of reducing wear in friction sliding.

An electrode development was needed with high efficiency and low costs as next generation solar cells. We attempted the electrode fabrication for a photoelectrochemical cell by immobilizing functional groups on a n-Si(111) surface. The immobilization was applied by hydrosilylation terminated with ester (hydrophobic) or carbonyl (hydrophilic) group. Results confirmed the immobilization on the Si surface by measuring ATR-FTIR and XPS.

We confirmed methyl termination on n-Si(111) surface by ATR-FTIR measurement, which was fabricated by a photo chloro-reaction and its methylation. The coverage of the methylation was about 63.7 %, and the surface was not re-terminated by hydrogen. Photoelectrochemical properties of the n-Si(111) was measured as an electrode for a photoelectrochemical cell, and an onset potential obtaining photocurrent for the methyl terminated n-Si(111) electrode was observed as negative shift at 70 mV comparing with that of the hydrogen terminated n-Si(111) electrode. Therefore, the negative shift would be expected for improving open circuit voltage towards solar cell. © 2012 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

The epitaxial growth of Ge on Si(111) covered with the 0.3 nm thick SiO 2 film is studied by scanning tunneling microscopy. Nanoareas of bare Si in the SiO 2 film are prepared by Ge deposition at a temperature in the range of 570˚C-650˚C due to the formation of volatile SiO and GeO molecules. The surface morphology of Ge layers grown further at 360˚C-500˚C is composed of facets and large flat areas with the Ge(111)-c(2 × 8) reconstruction which is typical of unstrained Ge. Orientations of the facets, which depend on the growth temperature, are identified. The growth at 250˚C-300˚C produces continuous epitaxial Ge layers on Si(111). A comparison of the surface morphology of Ge layers grown on bare and SiO 2-film covered Si(111) surfaces shows a significantly lower Ge-Si intermixing in the latter case due to a reduction in the lattice strain. The found approach to reduce the strain suggests the opportunity of the thin continuous epitaxial Ge layer formation on Si(111).

Composites of Maghnite-H, a Montmorillonite sheet silicate clay, exchanged with protons, and Poly(3,4-ethylenedi-oxythiophene) (PEDOT) were prepared by in situ chemical polymerization of the 3,4-ethylenedioxythiophene, without the use of solvent or oxidant. The effect of changing monomer/clay ratio was studied and the resultant composite structures were characterized by Inferred spectroscopy, 27 Al and 13 C Solid-State NMR spectroscopy, scanning electron mi-croscopy and powder X-ray diffraction. All analyses are consistent with a structure were the polymer is (partially) in-tercalated into the clay structure, which in favourable cases lead to exfoliation. The presence of the clay in the polymer leads to a desired increase in thermal stability as witnessed by thermogravimetry.

Due to their light weight, high corrosion resistance and good heat conductivity, aluminium alloys are used in many industries today. They are suitable for manufacturing many automotive components such as clutch housings. These alloys can be fabricated by powder metallurgy and casting methods, in which porosity is a common feature. The presence of pores is responsible for reducing their strength, ductility and wear resistance. The present study aims to establish an understanding of the tribological behavior of high pressure die cast Al A380M and powder metallurgy synthesized Al 6061. In this study, dry sliding wear behavior of Al A380M and Al 6061 alloys was investigated under low loads (1.5 N – 5 N) against AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration and frequency of 10 Hz. Wear mechanisms were studied through microscopic examination of the wear tracks. This study revealed that due to combined effect of real area of contact and subsurface cracking, wear rate increased with increasing porosity content. The difference in friction and wear behavior between received Al A380M and Al 6061 is attributed to their hardness differences.

In this work, erosion tests were performed to study the behavior of an aluminium alloy known as AISI 6061-T6 against the impact action of aluminium oxide abrasive particles. This material was selected because of its high ductility and tenacity. An erosion rig based on that in ASTM G76-95 was used to conduct the tests. The alumina particles had a particle size between 300 and 400 µm. Four incident angles, 30˚, 45˚, 60˚ and 90˚ were used to conduct the erosion tests. The particle velocity and the abrasive flow rate were 24 ± 2 m/s and 63 ± 0.5 g/min. The room temperature was between 35˚C and 40˚C. Chemical analysis of the material and abrasive particles were obtained using energy dispersive X-ray analysis (EDS). SEM images were employed to identify the wear mechanisms, which were characterized by high plastic deformation. The erosion rates were obtained and the results indicated that the maximum erosion damage was achieved at 30˚ reducing progressively at normal incidence.

High voltage lines are one of the main ways for carrying electric energy. To do so high voltage in-sulators are needed to insulate these lines from the supporting towers. Glass, ceramic and polymer insulators are widely used. Generally high voltage insulators are exposed to weather where humidity, from rain and moist, together with pollution allows accumulation of unwanted material on the surface of the insulator. Cleaning procedures are then needed to remove such material and avoid short-circuiting. The most commonly used cleaning methods are hand cleaning using chemicals that need turning off the main and water jet, which allows keeping the line in service. In this work we explore the possibility of using laser ablation for cleaning high voltage ceramic insulators. It is demonstrated that cleaning can be accomplished by a two-step process. First a Q-switched Nd: YAG laser is used to ablate the unwanted material. The second step is to use a free running Nd: YAG laser to restore the surface hydrophobicity of ceramic insulator, which is affected in the first process step.

TiO2 thin films were prepared on glass substrates using the PLD (Pulsed Laser Deposition) technique. In order to carry out the ablation process, a Nd:YAG laser was used emitting in 1064 nm wavelength at 10 Hz repetition rate, set up for operating in both single-pulse and multi-pulse regimes. A comparison of the deposition rate, the optical and morphological properties of the layers obtained from both ablation regimes was made, which showed that the multi-pulsed ablation produced layers with a higher surface quality and better optical properties.

In this work, a modification of the sugarcane bagasse is performed, in order to obtain organic catalysts. The bagasse analysis is performed using X-ray diffraction (XRD) and Fourier Transformer Infrared Spectroscopy (FTIR), which indicated that characteristic peaks determined its chemical compounds. In addition, Scanning Electron Microscopy (SEM) is used to know the morphology. Finally, a discoloration test is conducted on an azo compound (methylene blue) in an aqueous medium, obtaining an efficiency of 98.6%.

In this paper, a method that uses the Vickers hardness to estimate the yield stress of a metallic material with taking account of residual stress is proposed. Although the yield stress of bulk metal can be evaluated by a tensile test, it cannot be applied to local yield stress varied by surface modification methods, such as the peening technique which introduces high compressive residual stress at the surface. Therefore, to evaluate the local yield stress employing a relatively easy way, the Vickers hardness test was conducted in this paper. Since the Vickers hardness depends on both the residual stress and the yield stress, the relationship between the residual stress and the Vickers hardness was experimentally examined. It was concluded that the yield stress of the surface treated by several peening techniques can be estimated from the Vickers hardness once this has been corrected for residual stress.

The interpenetrating polymer networks (IPN) thin film with the –C=O group in one network and the terminal –N=C=O group in another network on an aluminum substrate to reinforce the adherence between IPN and aluminum through interfacial reactions, were obtained by dip-pulling the pretreated aluminum substrate into the viscous-controlled IPN precursors and by the following thinning treatment to the IPN film to a suitable thickness. The interfacial actions and the adhesion strengths of the IPN on the pretreated aluminum substrate were investigated by the X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and strain-stress(-) measurements. The XPS and FTIR detection results indicated that the elements' contents of N, O, and Al varied from the depths of IPN. The in-terfacial reaction occurred between the –N=C=O group of IPN and the AlO(OH) of pretreated aluminum. The in-creased force constant for –C=O double bond and the lower frequency shift of –C=O stretching vibration absorption peak both verified the formation of hydrogen bond between the –OH group in AlO(OH) and the –C=O group in IPN. The adherence detections indicated that the larger amount of –N=C=O group in the IPN, the higher shear strengths between the IPN thin film and the aluminum substrate.

Oil Vapor recovery is a critical process in downstream chemical industries, in oil and gas industries and in environmental protection. For that purpose, highly-efficient absorbent materials for vapor recovery are in high demand and their associated adsorption kinetics is of great importance for their performance. As oil vapor consists of multiple components with different physical and chemical properties, modeling the overall adsorption kinetics of activated carbon for multi-component oil vapor is essentially valuable for industrial applications. In this work, we developed a comprehensive model of multi-component gas adsorption kinetics on activated carbon in a packed-bed reactor and numerically solved the model by the finite element method. The predictions from the model are all in the reasonable range indicating good validity of the model. Some dimensionless parameters are also derived to further investigate the prediction results.

We investigated the adsorption to granular activated carbon of two pharmaceuticals (carbamazepine and sildenafil citrate) and a personal-care product (methylparaben) in aqueous solution, characterized the carbon, and evaluated its influence on the kinetics and adsorption equilibrium of the compounds under study. We adjusted data for the analysis of equilibrium to Langmuir and Freundlich models of adsorption isotherms and described adsorption rate using pseudo first- and second-order models; that same analysis was made on the basis of the behavior of the initial rate. In addition, we analyzed the potentiality of a nonlinear adjustment for studying kinetics and equilibrium of adsorption, an approach requiring neither knowledge of equilibrium conditions nor a-priori hypothetical suppositions regarding the order of reaction. The results indicated that the nonlinear model was capable of describing adsorption kinetic behavior, in order to determine concentrations adsorbed at equilibrium, adsorption rates of the system, maximum adsorption capacity, and global rate constant. Granular carbon exhibited an adsorption capacity for carbamazepine and methylparaben of ca. 323 mg/g and for sildenafil citrate of ca. 142 mg/g, though with slow adsorption kinetics characterized by average adsorption times of at least 168 h.

Antifouling paints are the most reliable way to prevent biofouling of submerged surfaces. The high toxicity of organotin paints, prompted us to look for ideas to develop paints that do not present environmental risks. In this work, we prepare a painting by a modification of acrylic acid monomer containing a free carboxyl group. The biocide that is selected is the perfluorinated chain with eight carbons. Chemical modifications of the resins are made through a radical reaction. The magnitudes of changes are monitored by proton nuclear magnetic resonance NMR, gel permeation chromatography (GPC) and the light scattering (LS) at a fixed angle 90 °. The glass transition temperature of the surfactant is obtained by the differential scanning calorimetry (DSC). The antifouling properties of the paint are followed by exposure of panels to the marine environment by visual observation.

Powder iron monosilicide with certain structure exhibits magnetic properties and can be used as an alloying additive in the production of electrical steels and silicon alloys with special physical and chemical properties. From this point of view, development of the energy-saving technology for receiving such a valuable alloying agent with the disposal of secondary waste is an urgent task. For this purpose, the method of joint aluminothermic reduction of preliminary mechanically activated metallurgical waste is offered. Recently, a method for combining the self-propagating high-temperature synthesis and preliminary mechanical activation for obtaining metal powders with certain phase composition and structure is considered as one of the efficient ones. As the initial materials for obtaining iron monosilicide, the waste (or converter) slags of the Alaverdi copper-smelting plant and molybdenum slags of the Yerevan Pure Iron Plant are used. Besides the mentioned slags, NaNO3 and CaO are added. Properties and structure of the received silicide depend on the contents, quantity of components, and the mass relation of two wastes in the burden. Therefore, the processes of structure formation of the iron monosilicide received from metallurgical waste are investigated. Studies have shown that the best results are obtained in case of waste and molybdenum slag relation of 4:1, when the 60-minute grinding in the vibromill leads to a significant increase in the mechanical activation of the burden. At this relation of FeO and SiO2, a condition is created for receiving iron monosilicide showing magnetic properties. On the whole, those transformations lead to a decrease in the reaction activation power of the interacting substances, an increase of the reactivity capacities, as well as to a new original course of reactions and new modified materials.

Behaviour of excited Ru(bpy)3^(2+) bound to the surface of water-soluble single-walled carbon nanotubes on addition of other cations have been investigated by measuring Ru(bpy)3^(2+) luminescence. In contrast to what was observed with a solution containing rod-like aggregation particles of Nafion, we found that Ru(bpy)3^(2+) has a stronger attraction than that of other cations to the sulfonic groups on the carbon nanotubes. Such a difference is attributed to the unique micro- environmental characteristics of the molecular assemblies.

The article is deals for new experimental equipment for effective test adhesion for selected coating STEEL, applied cold on the coated metal sheet with Al (aluminum). Explanation to the word STEEL: STEEL coating has significant anti- corrosive properties and he is resistant for main oxidizing agents such as acids, alkalis, salt vapors etc. Resists tem- peratures to 600?C and create an elastic film that is resistant to abrasion, as soon as it was to complete po-lymerization. It is very simple to applied to metallic and nonmetallic surfaces. Dries quickly and is dry to the touch after 90 to 120 seconds. STEEL is the best possible solution anywhere, if needs arises powerful local protection against atmospheric and corrosive agents or to elevated temperatures. STEEL is also useful as a method for protect of welds on stainless steels instead of traditional staining procedures. Broad application is in automotive industry to modify the surfaces of block vehicle, car-body repairs, welds needing protection, in heating industry for example boilers, in air condition with heat exchanger and in shipping industry. [1-3].In experiments with a new test equipment is showed that for bending radius of interval from range R11 to R35 there is a change deposited coating STEEL from original coating Al and this coating was part of test metal sheet of thickness 1.5 mm. In the next stage of solution was developed technological process, which allowed increase of adhesion coating STEEL for bending up to or maximum 180? (shape U). Result of new technology is documented in article. Experiments was implementing with cooperation of the Masaryk University in Brno.

In order to select the best adsorbant for CO2 sequestration, this study deals the interaction between clay, Triassic sandstone and Jurassic evaporate and CO2. These materials have been used as sorbents. To choose the adequate geological layers for sequestration and with minimum risk of leakage, adsorbent characterizations were investigated using X-ray diffraction, SEM and surface area analysis, structural and textural shapes of these materials have been investigated too. The elution chromatography in gaseous phase has been employed to determine the adsorption iso-therms of adsorbed CO2 for each adsorbent. Then, the treatment of the experimental data allowed us to compare each CO2/adsorbent couple. The adsorption isotherms were modeled using the Langmir and Freundlich models. A thermodynamic comparison between the different adsorbents will also be provided. Experimental results show that clay and Triassic sandstone have the highest rate of adsorption amount. It has been also found that the Langmuir model is the most appropriate one to describe the phenomenon of CO2 adsorption on clay. However, for the other adsorbents (i.e. Triassic sandstone and Jurassic evaporates) the two-models are adequate.

Both fullerene (C 60 as well as fulloropyrrolidine was subjected to doping with groups III, IV and V respectively. The doping effect was determined in terms of bond lengths, total dipole moments, charge distribution, HOMO–LUMO band gap energy as well as other thermodynamical parameters. For Caculated band gap energies PM3 quantum mechanical method shows comparable values as compared with ab initio results. Results showed an increase in total dipole moment as well as band gap energies especially for doped fulleropyrrolidine structures. Calculated thermal parameters indicate a stability of fulleropyrrolidine doped structures as compared with other doped fullerenes. It is concluded that, good band gap energies are achieved with fulleropyrrolidine metal doped structures.

The adsorption of CO, CO2, NO and CO2 gas molecules on different chiralities of single boron nitride nanotubes (BNNTs) is investigated, applying the density functional theory and using basis set 6-31 g (d,p). The energetic, electronic properties and surface reactivity have been discussed. We found that the best BNNT for adsorbing the CO, CO2, NO and NO2 gas molecules is (5,0) BNNT with adsorption energy of −0.27, −0.37 eV, −0.23 and-0.92 eV, respectively. Also, the electronic character of (5,0), (9,0), (5,5) and (6,6) BNNTs is found to be not affected by the adsorption of CO, CO2, NO and NO2 gas molecules. It is found that the dipole moments of zigzag (5,0) and (9,0) BNNTs are always higher than the armchair (5,5) and (6,6) BNNTs. Also, it is noticed that the highest dipole moment is for (9,0) BNNT.

The adsorption of α-chymotrypsin onto plant biomass charcoal (PBC), which was prepared from plant biomass wastes such as bagasse and dumped adzuki beans by pyrolysis, has been examined. The PBC was characterized by SEM, specific surface area, and pore size distribution. The adsorption isotherms were successfully correlated by the Freundlich equation. The amount of α-chymotrypsin adsorbed on PBC was dramatically dependent upon the solution pH and temperature. Maximum adsorptions of α-chymotrypsin on adzuki bean charcoal and bagasse charcoal were observed at weak acidic and near neutral pH, respectively. The amount of α-chymotrypsin adsorbed on PBC decreased with an increase in the concentration of salts. Plots of the amount of α-chymotrypsin adsorbed on PBC versus temperature exhibited an optimum temperature.

We want to conclude on the interest of the “crimping” process used to produce the glass wool and to make a comparison for anisotropic factor obtained from structural property (air permeability) as well as thermal property (thermal conductivity and diffusivity). The main structural (densities, porosity, specific surface, air permeability) and the thermal (conductivity, diffusivity, heat capacity) characteristics of this glass wool are presented. Thermal results are determined by using several methods (Hot disc (HD), Heat Flow Meter (HFM) and Guarded Hot Plate).

New magnetic air-stable nanogranular Fe thin films of 10 ± 1.2 nm thickness were prepared onto silicon wafers at 150℃ under inert atmosphere by controlled Chemical Vapor Deposition (CVD) of triiron dodecacarbonyl (Fe3(CO)12). These thin films, composed of sintered elemental Fe nanoparticles of 4.1 ± 0.7 nm diameter, are protected from air oxidation by a very thin carbon layer. The saturation magnetization of these thin Fe coatings was found to be close to that of bulk iron. The electrical resistivity behavior of the ferromagnetic thin films is similar to that of a semiconductor. In the present manuscript, these Fe thin coatings on Si wafers have been used as a catalyst for synthesizing crystalline carbon nanotubes (CNTs), by CVD using ethylene as a carbon precursor.

The aim of this study is to report batch adsorption results of Cd (II) and Cr (VI) onto Algerian bentonite. The equilibrium adsorption process was achieved at about 120 min contact time. The kinetic and isotherms aspects of Cr (VI) and Cd (II) adsorption were investigated by varying operation parameters such as pH (0.5 - 6), initial Cd (II) and Cr (VI) concentrations (50 - 200 mg/l) and temperature (293.15 K - 343.15 K). The optimum conditions obtained were: pH = 6.0 and 4.0 for Cd (II) and Cr (VI) respectively, initial concentrations of Cd (II) and Cr (VI) = 50 mg/L and T = 293.15 K. The kinetic of the adsorption process was studied by application of the most important kinetic models namely the pseudo-first order, the pseudo-second order and Elovich equations. The results showed that the pseudo-second order model fitted well the adsorption data of Cr (VI) whereas, and the Cd (II) adsorption data fitted best the Elovich equation. The equilibrium data fitted best the Langmuir isotherm, and the maximum adsorption capacity was determined through this model and was found to be 13.17 and 12.61 mg/g for Cd (II) and Cr (VI) respectively. The temperature had a reverse effect on the Cd (II) and Cr (VI) adsorption; our results showed that the removal efficiency increased to 82.4% and 55.70% for Cd (II) and Cr (VI) when the temperature decreased to 293.15 K. The negative figures of the Gibbs free energy ΔG˚ads values range from −15.23 kJ/mol to −14.37 kJ/mol for Cd (II) and from −9.70 kJ/mol to −9.64 kJ/mol for Cr(VI) at 293.15 K to 343.15 K showed that the adsorption process is spontaneous and favourable. These results confirmed the ability of the low-cost Algerian natural bentonite to efficiently and competitively adsorb the two toxic elements investigated: cadmium (II) and chromium (VI).

In this study the mechanical and erosion wear behavior of bamboo fiber reinforce epoxy composites filled with Cement-ByPass Dust (CBPD) were studied. The effect of CBPD content and alkalization on the various properties of these composites was also investigated. Taguchi's orthogonal arrays are used for analysis of experiential results. It identifies significant control factors influencing the erosion wear and also outlines significant interaction effects. Analysis of variance (ANOVA) test has also been performed on the measured data to find the most significant factors affecting erosion rate. Finally, eroded surfaces of both untreated and alkali treated bamboo fiber reinforced composites were characterized using SEM.

Based on starch and series of alkyl benzene sulfonic acid as the materials, a novel carbon-based solid acid catalyst is synthesized using hydrothermal method. This catalyst exhibits much higher catalytic activity in the reaction of esterification of Mono-fatty alcohol polyoxyethylene maleate esters with 1,4-butanediol. The structure of carbon-based solid acid catalyst was charactered by IR and XRD, characterizations showed that this catalyst exhibited high –SO3H loading. Reusability of the carbon-based solid acid catalyst for esterification showed that after recycling five times the activity remained unchanged.