Valentina Zin

• Materials Engineering, Metallurgy
• Researcher at Institute of Condensed Matter Chemistry and Technologies for Energy, Italian National Research Council

This paper investigates how negative substrate bias voltage and sputtering pressure influence tungsten coatings deposited via radiofrequency magnetron sputtering. Increasing the absolute value of negative bias voltage (up to −150 V) of the substrate results in higher mass density, higher surface roughness, better crystallinity, improved adhesion, a...

Medical implants are requested to meet stringent requirements to ensure their safety and efficacy over extended periods within the human body. The use of surface modification techniques, such as nitriding, is essential in advancing the performance and lifetime of implant materials. The innovative use of High Power Impulse Magnetron Sputtering (HiPI...

Correction for ‘Plasma-assisted fabrication of ultra-dispersed copper oxides in and on C-rich carbon nitride as functional composites for the oxygen evolution reaction’ by Mattia Benedet et al. , Dalton Trans. , 2024, https://doi.org/10.1039/d4dt02186j.

Amorphous carbon nitride functionalized with ultra-dispersed copper oxides through a plasma-assisted route holds promise as an electrocatalyst for water splitting applications.

Nanocomposites of sodium alginate (SA) and TiO 2 nanoparticles have gained attention in the last decade for their versatile uses in several applications. Indeed, TiO 2 is particularly appealing for its photocatalytic and antimicrobial activity and inherent safety. In this paper, TiO 2 nanoparticles are successfully embedded, synthesized by a microw...

This work aimed to investigate the effect of the burnishing surface treatment on the tribocorrosion resistance related to Ti6Al4V specimens, in the framework of the head-neck tribo-pair characterising a total hip replacement. The experimental procedure carried out started by choosing the specimens referred to different burnishing conditions togethe...

In this work, a rapid microwave-assisted hydrothermal method under mild conditions is investigated for the preparation of the Eu3+:YPO4 (5 mol % Eu) luminescent material, which belongs to a large family of phosphates that, when doped with lanthanide ions, acquire specific luminescence properties used primarily as phosphors for modern light sources...

The development of tailored microstructures of Multi-principal element alloys (MPEAs) is currently a hot topic in physical metallurgy. The most targeted systems are equimolar alloys composed of 3d transition metals including the so-called Cantor alloy (i.e. CoCrFeMnNi) and derivatives such as CoCrFeNi and CoCrFeNiAlx. Powder metallurgy is a promisi...

Source for Production of Ion of Deuterium Extracted from Rf plasma (SPIDER) and Megavolt ITer Injector and Concept Advance (MITICA) experiments are actively cooled by ultrapure water (UPW) to electrically insulate in-vessel components that are polarized to high voltage levels. Water circulating in cooling pipes reacts with wetted surfaces made of c...

In this work, the infiltration of TiN powders by electrophoretic deposition (EPD) in aqueous media was considered as alternative method to reduce the size craters and the roughness of commercial porous Ti substrates. Ti substrates can be used as suitable supports for the deposition of dense hydrogen separation TiNx-based membranes by physical vapor...

In this article, the depositions and functional characterizations of Ta-N and Ta-Al-N coatings for protection purposes, grown by reactive high-power impulse magnetron sputtering onto silicon substrates, are described. Nitride films were grown while changing the substrate polarization voltage (i.e., the applied bias voltage) during the process. More...

Sputter deposition of multiprincipal element alloys (MPEAs) is a relatively new field of research with high functional potential. The multicomponent design space is immense and practically unexplored. An important obstacle for academic research of such sputtered films is the availability of single‐alloy targets and technical difficulties in using c...

A novel approach for the deposition of Au-based coatings on NiTi components was proposed to give rise to innovative SMA-based products for the fashion, luxury, and watchmaking fields. Different Au-Cu and Au-Ag-Cu alloys (with confidential compositions within the color designations 2N, 4N, and 5N) were deposited by magnetron sputtering on superelast...

In the present work, surface engineering of Ti6Al4V, produced via selective laser melting parts, was carried out with the aim of investigating how surface features of substrate may improve the coupling with AlTiN coatings deposited by physical vapor deposition reactive high-power impulse magnetron sputtering. In particular, the work highlighted how...

This scientific work aims to optimize the preparation of titanium nitride coatings for selective H2 separation using the Reactive High Power Impulse Magnetron Sputtering technology (RHiPIMS). Currently, nitride-based thin films are considered promising membranes for hydrogen. The first series of TiNx/Si test samples were developed while changing th...

This study deals with a deep investigation on chemical, structural, mechanical and tribological properties of TiBx coatings produced by means of PVD techniques, i.e. Direct Current (DC-MS) and High Power Impulse Magnetron Sputtering (HiPIMS). TiBx coatings were deposited onto Si wafer, at different substrate temperatures (200, 300 and 400 °C). DC-...

BaCe 0.65 Zr 0.20 Y 0.15 O 3-d-Ce 0.85 Gd 0.15 O 2-d (BCZ20Y15-GDC15) is currently one of the most studied composites for applications as dense ceramic membranes for H 2 purification and membrane reactors. However, the efficiency of the structure represents a crucial issue to be solved for its practical uses. In this work the optimization of suitab...

Microwave assisted sintering of Na-β’’-Al2O3 in single mode cavities was accurately investigated. The use of single mode cavity allowed monitoring the parameters affecting the sintering process, like the forward power, together with the temperature evolution, making possible to perform energy efficiency and specific energy consumption evaluations....

Nanolubricants, thanks to their ability to reduce friction and wear, are increasingly studied in the transport and automotive sectors. These systems are generally produced with a two‐step procedure by dispersing nanoparticles into base oils. Very recently, one‐step methods have received increasing attention for the production of highly stable nanos...

A titania (TiO2) - hydroxyapatite (HA) bi-layered material, with a target surface design, was obtained by means of a two-step process on the surface of Ti substrates with three different pristine morphologies and topographies. A dense, compact and crystalline titania inter-layer was obtained via Metal Organic Chemical Vapor Deposition, and a homoge...

Three differently treated titanium substrates to be used in dental implant applications and with different surficial morphology were coated with titanium dioxide (TiO2) films by using Low-Pressure Metal Organic Chemical Vapor Deposition (MOCVD). No literature references were found on the performance evaluation of the TiO2 MOCVD coatings on substrat...

In order to investigate a protective coating approach for nuclear applications, two different aluminum rich layers were deposited on T91 steel coupons: Ti-Al-N films were grown via High Power Impulse Magnetron Sputtering and AlO coatings were produced by Radio Frequency Magnetron Sputtering. In this exploratory work, coated specimens were corrosion...

To withstand oxidation at a temperature ≥ 850 °C, an optimized Ti1−xAlxN coating was grown via reactive High Power Impulse Magnetron Sputtering (HiPIMS) technology on three identical Ti0.48Al0.48Cr0.02Nb0.02 billets. Different substrate surface pre-treatments were designed to increase performance: i) mechanical polishing, ii) mechanical polishing c...

Additives responsive to magnetic fields can be easily manipulated under the action of external stimuli and employed in various sectors, with great feasibility. In this work, suspensions of goethite nanorods were developed for anti-friction and anti-wear purposes. Goethite represents a promising additive in lubricants promoting the formation of a pr...

Lead alloys are attractive candidates as coolants for future generation nuclear reactors (fast reactors). Unfortunately, they easily corrode structural steels of reactors. To mitigate this phenomenon, surface protective coatings may be applied. In this study, T91 steel (Cr9Mo1) samples were coated with aluminum oxide coatings (Al-O) deposited by ra...

This work is devoted to the study of composite system of liquid crystal 4-(trans-4-n-hexylcyclohexyl)-isothiocyanato-benzene (6CHBT) doped with lath-like goethite magnetic nanoparticles with the concentration of 0.01 vol%. The structural transitions in ferronematic samples were observed by dielectric measurements in a capacitor made of ITO-coated g...

Hard coatings represent a suitable resource to protect structural materials against oxidation and wear phenomena. Physical Vapour Deposition techniques usually require elevated deposition temperatures to accomplish desired performance, becoming incompatible with sensitive substrates. High Power Impulse Magnetron Sputtering technology allowed obtain...

Goethite (α-FeOOH) nanorods have been synthesized using two different methods, by aging at different temperatures of ferrihydrite suspensions obtained through co-precipitation, or by fast conversion of ferrihydrite through ultrasonic irradiation. The synthesis method and parameters influenced the size and shape of nanoparticles. Stable colloidal su...

The Ti-48Al-2Cr-2Nb intermetallic alloy was coated by using a mixed titanium-aluminum nitride with the aim of improving its oxidation resistance. The protective TiAlN coatings were obtained by reactive High Power Impulse Magnetron Sputtering (HiPIMS) technique. The surface of the Ti-Al alloy was prepared for HiPIMS according to different methods; t...

A High Power Impulse Magnetron Sputtering (HiPIMS) method for depositing TiAlN environmental barrier coatings on the surface of Ti-48Al-2Cr-2Nb alloy was developed in view of their exploitation in turbine engines. Three differently engineered TiAlN films were processed and their performance compared. Bare intermetallic alloy coupons and coated spec...

In this work, two different nitride coating typologies designed to answer to two different technological problems are presented. They are deposited by High Power Impulse Magnetron Sputtering (HiPIMS) technology which permits to produce high performance coatings thanks to an ultra-dense plasma leading to a high ionization degree of the sputtered mat...

This work deals with a tribological study on the effects of the addition of carbon nanostructures to a conventional lubricant oil for refrigeration and air conditioning purposes. Wear tests were carried out to investigate the influence of nanoadditives concentration on anti-friction and anti-wear properties of nanolubricants. The most promising sys...

Enhancing the tribological performance of lubricants with nanoparticle additives is a recent challenge. The purpose of this study was to investigate the potential advantage of nanolubricants, a new class of advanced lubricants integrating nano-sized materials, to reduce friction and wear processes, in view of applications in compressors for refrige...

The addition of nanoparticles in lubricating oils recently demonstrated to reduce the coefficient of friction and to increase the load-carrying capability of lubricant in coupled surfaces. In this work, different kinds of nanoparticles were tested as additives to engine oil to improve lubrication: copper and titanium oxide nanoparticles and single...

In the last years, various applications have been proposed for nanofluids in the Heating, Ventilation, Air Conditioning and Refrigeration (HVACR) field; their use as primary and secondary fluids, also as lubricants, has been kept into account to improve systems performance.The present work was developed to test the applicability of nanofluids as lu...

SEM–FIB and XRD results showed a significant modification of films' microstructure due to selected deposition parameters: it goes from dense-columnar (high crystallite size) at low working pressure and/or high gas mass to nano-porous (small grains) at high pressure and/or low gas mass. This means that the momentum flux carried to the substrate cons...

The work illustrates the preparation of stable suspensions of single-walled carbon nano-horns (SWCNHs) in engine oil and shows their tribological behavior at different temperatures. The suspension stability was verified by dynamic light scattering, and the viscosity of suspensions was measured. Stribeck test was used to evaluate the tribological pe...

Binary alloy Cu–Ni nanoparticles were synthesized by sonoelectrochemical technique from aqueous bath in presence of Na-citrate as complexing agent, to allow co-deposition of Cu and Ni. Alloy Pulsed Electro-Deposition (PED) was carried out to study nucleation kinetic and the effects of pH and surfactant on the final product physical and chemical pro...

Cu nanoparticles (NPs) are widely studied to understand how they work in lubricant oils to improve its tribological properties. This paper describes the synthesis and characterization of Cu NPs of different size (φ = 60 and 130 nm) carried out in EG and the dispersion procedure used to prepare nanolubricants containing different amounts of NPs (0.0...

Several studies have been recently carried out on nanofluids due to their potentiality to enhance thermo-physical and tribological properties of common fluids, especially when used in thermal energy systems. In particular, the available literature shows that the use of nano-oils in a refrigeration plant as compressor lubricant allows getting better...

The study describes synthesis of FeCo nanoparticles by using the pulsed sonoelectrochemical technique, a method which couples an electrochemical process with the employment of high power ultrasound. An ultrasonic horn is also used as the working electrode and is subjected to a pulsed galvanic current and pulsed out of phase ultrasound. Nanoparticle...

During the production of low carbon steels from recycled scrap, surface cracking during hot working is commonly observed. This phenomenon, known as hot shortness, arises from the preferential oxidation of iron and subsequent enrichment of the residual element copper. Copper tends to be enriched at steel/scale interface by preferential oxidation of...

This work is about the production of metal nanopowders by pulsed sonoelectrochemical technique, optimized at University of Padova. The method couples an electrochemical process with the employment of high power ultrasound: an ultrasonic horn is also used as the working electrode and it is subjected to pulsed applied galvanic current and pulsed out-...

This study describes synthesis of Fe–Cr alloy nanoparticles by using a method which couples electrodeposition of metals with the employment of high power ultrasound. The production of alloyed nanoparticles was performed using a 20 kHz titanium alloy horn ultrasound generator, a “sonoelectrode” generating short current pulses (tON) triggered and fol...

Il fenomeno “HOT-SHORTNESS” affligge principalmente gli acciai prodotti con forno ad arco elettrico ed è causato dal residuo di rame presente nel rottame impiegato per la produzione. Esso, infatti, è responsabile della formazione di cricche superficiali durante le lavorazioni di forgiatura e laminazione a caldo. Scopo del presente lavoro è indagar...

Nel presente lavoro è stata trattata la produzione di nanopolveri metalliche con il metodo sonoelettrochimico a pulsione, ottimizzato presso l’Università di Padova. Sono state sintetizzate particelle nanometriche di lega FeCo e FeCr a diverse temperature del bagno elettrolitico, allo scopo di studiare e determinare l’influenza della temperatura di...

This work is about the production of metal nanopowders by pulsed sonoelectrochemical technique, optimized at University of Padova. Nanoparticles made of FeCo and FeCr alloy were synthesized at different bath's temperature, in order to study and evaluate the influence of this parameter on process efficiency and nanoparticles' features. Produced mate...

The present work describes the production of platinum nanoparticles from aqueous chloroplatinic solutions in the presence of low-frequency high-power ultrasound (20 kHz) on titanium alloy electrodes. The production of this new type of Pt nanoparticles was performed galvanostatically at (298 ± 1) K using a newly designed experimental set-up and ‘son...

This study describes synthesis of FeCo nanoparticles by using a method which couples electrodeposition of metals with the employment of high power ultrasound. A 20 kH titanium alloy horn ultrasound generator, a “sonoelectrode”, generated short current pulses which were triggered and followed by ultrasonic pulses. The primary role of ultrasound is t...

This paper describes the production of alloy nanoparticles of Co:Fe ratio 65:35 from Aotani solutions in the presence of high power ultrasound (20 kHz). The production of this new type of alloy nanoparticles was performed potentiostatically and galvanostatically at (298 ± 1) K using a newly designed experimental set-up i.e. a ‘sonoelectrode’ produc...

In this work the development and the characterization of a sonoelectrochemical process for the synthesis of gold and silver nanoparticles from sulfite based electrolytes was studied. The solution chemistry was chosen in alternative to electrolyte composition of chemical deposition processes and selected because of its low environmental impact and c...