Oxide Films Research Articles

Optimization of the Synchronous Pressurization Process for the Elimination of Double-Layer Oxide Film Defects

Optimization of the Synchronous Pressurization Process for the Elimination of Double-Layer Oxide Film Defects

The effect of oxide scale on the corrosion resistance of SUS301L stainless steel welding joints

The effect of thermal oxidates on the corrosion of SUS301L stainless steel welded joint was investigated using electrochemical corrosion test and TEM microstructure observation. Activation dissolution behavior without passive region was found in the potentiodynamic polarization curves on the welding zone and heat affected zone. The activation corrosion is related to the preferential dissolution of the NiFe layer at the interface between chromium oxide and substrate. However, the passive region in the polarization curve reappears after the unstable NiFe dissolves in the salt-frog test. The passivation behavior due to microstructure evolution beneath the thermal oxide film was discussed during the corrosion process.

Effect of surface treatment on oxidation film of 55SiCr spring steel wire

Abstract In this work, the surface pretreatments of 55SiCr spring steel wire rods were conducted using shot blasting and phosphating. After drawing, the steel wire was heated at 950°C × 15 s, followed by oxidation treatment with high-temperature steam or air for 3 seconds, and tempering treatment at 520°C. The effects of different surface treatment methods on the surface oxide film of spring steel wire were studied using stereomicroscopy, SEM, EDS, and XRD. The results showed that the steel wire surface oxide film with phosphating pretreatment was thicker and easy to fall off. The thickness of the oxide film formed by phosphating pretreatment samples increased by 2.1 um (high-temperature steam) and 0.3 um (air) compared to the shot-blasting samples under different oxidation atmospheres. High-temperature steam oxidation treatment significantly increased the thickness of the oxide film by 0.65 um (shot blasting) and 2.45 um (phosphating) under different surface pretreatment conditions. The outer surface of the oxide film turned black with high-temperature steam oxidation treatment and turned yellowish brown with air oxidation treatment. By both above oxidation treatments, the oxide film showed a multilayer structure, with enrichment of Cr and Si on the inner side.

Comparative studies of the long-term corrosion behavior of Zr-Sn-Fe-Cr-Ni alloys in pure water at 360°C/18.6 MPa with high and low dissolved oxygen content

This study compared the uniform corrosion behavior of Zr-Sn-Fe-Cr-Ni alloys in deionized water at 360°C/18.6 MPa with high and low concentration of dissolved oxygen (DO). It was found that high concentration of DO accelerated the corrosion rate of the Zr-Sn-Fe-Cr-Ni alloys and led to an earlier corrosion transition. Increased DO concentration resulted in a higher content of t-ZrO2 near the metal-oxide interface, which induced greater in-plane compressive stress in the oxide film and a high-level phase transformation from t-ZrO2 to m-ZrO2. This, in turn, led to an earlier occurrence of corrosion transition.

On the corrosion resistance of the CoCrFeMnNi high entropy alloys in chloride-containing sulfuric acid solutions

The electrochemical reactivity of the high entropy Cantor alloy (CoCrFeMnNi) was investigated via potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and surface analysis as a function of chloride content, in sulfuric acid solutions. The results revealed that corrosion mechanism of the CoCrFeMnNi alloy at the corrosion potential, is a two-step mechanism, involving one adsorbed intermediate, similar to that of pure iron in the H2SO4, and this model provided a good description of the impedance data. X-ray photoelectron spectroscopy (XPS) surface characterization and impedance data fitting revealed that chloride ions do not alter the corrosion mechanism or the thickness of the surface oxide film. Instead, they affect the corrosion resistance by changing the composition of the oxide film. Additionally, this work demonstrated that the corrosion mechanism of the CoCrFeMnNi alloy varies with the applied potential, as evidenced by impedance measurements under potentiostatic polarization. Surface observations using scanning electron microscopy (SEM) and XPS analysis provided insights into the morphology and composition of the surface oxide film at different applied potentials, explaining the observed changes in impedance.

Fabrication of Self-Assembled Graphene Oxide Film and Its Application in Aqueous Zinc Metal Batteries.

Fabrication of well-dispersed thin graphene oxide (GO) films (GOFs) has always been a challenge. Herein, a quick preparation method for GOFs was developed using our homemade GO with a large lateral size. The film can be prepared in less than 2 h via a metal framework-induced self-assembly process. The thickness of the films can be as thin as ∼15.5 μm, which will be thinner with compression. When it is used as a flexible modification layer on the Zn metal for aqueous Zn-ion batteries, Zn can grow along the [010] direction in plane and stack orderly along the [002] direction even on the Cu substrate with GOF through epitaxial plating owing to negligible lattice mismatch between the (002) plane of Zn and the hexagonal ring [also (002) plane for graphite] of GO. Meanwhile, the rich O groups on the GO film can provide abundant zincophilic points and promote uniform distribution of Zn2+ around the anode. Finally, dendrite-free and dense Zn stripping/plating can be achieved and well remained. The GOF@Zn symmetric cell reveals long cyclic stability of 1300 h at 1 mA cm-2 and 1 mA h cm-2. It still can remain at 350 h even at a very high current density of 10 mA cm-2 accompanied by a high areal capacity of 10 mA h cm-2. With the same plating amount of 5 mA h cm-2, the thickness of the plated Zn is only ∼10 μm with GOF modification, very close to the theoretical value of 8.54 μm, much thinner than that without GOF (∼18 μm), indicating very dense deposition. Full cells assembled with the GOF@Zn anode and the MnO2 cathode exhibit a capacity retention rate of 71% over 1000 cycles at 0.7 A g-1, showing much better cycling performance than that using bare Zn.

Laser cladding Ni60-SiC/Ti3SiC2 self-lubricating composite coatings on IN718 alloy: Wear mechanisms and oxidation behaviors

To enhance the service performance of IN718 alloy under severe working conditions, the self-lubricating composite coating of Ni60-SiC/Ti3SiC2 was fabricated on its surface using laser cladding. By systematically analyzing the microstructure and properties of composite coatings, the wear mechanism at different temperatures and the oxidation behavior at 800°C of coatings were discussed in depth. The results demonstrate that an increase in coatings’ microhardness by a factor of 1.9 to 3.1 over IN718 was achieved, benefiting from the fine-grained and solid-solution strengthening actions, and the hard phases such as C23C6, Ni3Si, TiC distributed diffusely inside the coatings. The tribological performance of coatings was also significantly improved, in which the coating with 10 wt.% Ti3SiC2 added had the lowest wear rates of 2.13 and 3.57×10-5 mm3/N·m at RT and 600°C, respectively, which were reduced by 82.74% and 87.43% compared to the substrate. When the test temperature changes from RT to 600°C, the main wear form of coatings changes from adhesive and abrasive wear to oxidative wear. With the Ti3SiC2 content increasing, the oxide film is gradually dense and uniform, and the oxidation resistance is significantly improved.

Sustainable recycling of pure aluminum from waste chips under supergravity-enhanced separation: A cleaning process

Large quantities of chips containing high levels of aluminum are always inevitably produced during machining process of aluminum products, which is a valuable renewable resource. In this paper, an environmental-friendly method for direct and continuous recovery of same-level recycled Al from waste chips under supergravity-induced was proposed. The oxide film covering the surface of the molten Al-chips was easily disrupted under super-gravity, and subsequently almost all of Al melt detached from the oxide film and flowed rapidly through the microporous ceramic foam filter, with a yield ratio of more than 97 %. During this process, all fine broken oxide-film particles and large amounts of primary iron-rich particles in the melt were captured in the complex channels of the filter, resulting in clean 1xxx series recycled Al with free inclusions and impurity iron content of less than 0.28 wt%. In addition, a sustainable process and a continuous centrifugal unit for recycling aluminum chips were designed, the economic and environmental advantages of which demonstrate the feasibility of sustainable regeneration of aluminum chip resources on an industrial scale via supergravity technique.

Enhanced SWIR Absorption in PMMA‐Coated TiN‐Based Metamaterial

AbstractAchieving highly efficient absorption in the short wavelength infrared (SWIR) spectral region is crucial for advancing numerous technologies. SWIR absorption enhances energy harvesting in solar cells, improves the sensitivity of infrared sensors, and enables precise control of thermal radiative properties in thermal emission devices. These advancements are essential for applications such as thermal imaging, night vision, and thermophotovoltaic systems. The study presents a simple, cost‐effective design of a polymer‐coated multilayer perfect absorber (MPA) metamaterial optimized for the SWIR spectral region. The proposed MPA structure is composed of four distinct layers: a top layer made of polymethyl methacrylate (PMMA) polymer, a second layer featuring arrays of circular titanium nitride (TiN) disks, a dielectric middle layer consisting of a pure zinc oxide (ZnO) film, and a bottom metallic layer formed by a thin film of TiN. The results demonstrate that the MPA achieves near‐perfect absorption, with a remarkable 99% efficiency centered at a wavelength of 1.3 µm. The absorption properties are further investigated with respect to various structural parameters to ensure better performance of the absorber. These absorbers hold great promise for applications in energy absorption, infrared sensing, thermal emission, and related fields.

Oxygen plasma-assisted magnetron sputtering deposition of non-stoichiometric Y2O3 films: Influence of oxygen vacancies on etching resistance

Yttrium oxide (Y2O3) films are widely used to protect equipment in plasma etching, a crucial technique in semiconductor processing, due to their exceptional resistance to plasma etching. Since oxygen vacancy affects the performance of Y2O3 and may impact physical etching resistance, the internal relationship necessitates further investigation. In this article, Y2O3 films with varying oxygen vacancy concentrations are prepared by reactive magnetron sputtering with the assistance of oxygen plasma. The formation and development of oxygen vacancies in cubic Y2O3 films and their impact on the physical etching resistance were investigated. The experiment results indicate that the accumulation of oxygen vacancies causes non-stoichiometry and the etching rate is significantly reduced. Combined with density-functional theory, it is revealed that oxygen vacancy distorts the lattice, which increases covalent YO bonding and the formation energy of atoms. Moreover, the vacancy line defects resulting from diffusion and aggregation of oxygen vacancies exert a similar influence on the adjacent yttrium and oxygen layers. The enhancement of physical etching resistance is attributed to the strengthened internal YO bonds led by increasing oxygen vacancy concentration in the cubic Y2O3 films without inducing phase transition. The discovery enriches the understanding of how plasma interacts with Y2O3, and the etching mechanism.

Development of transition metal oxide platforms for aptasensing of PSA in cell cultures.

In this study, a novel aptasensor based on a transition metal oxide-modified pencil graphite electrode (PGE) was developed for the diagnosis of early-stage prostate cancer (PCa) via monitoring the prostate-specific antigen (PSA), which is the main biomarker for PCa. Single-use PGEs modified with pulsed deposited manganese oxide (MnOx) film were used to attach the amino-terminated aptamer specific to the PSA via carbodiimide chemistry. The designed aptasensor was placed in an electrochemical cell containing ferri/ferrocyanide ions as a redox probe to measure the charge transfer resistances (Rct) of the electrode surface by electrochemical impedance spectroscopy (EIS) to follow the response of each modification step. The effect of the medium pH on the ionic structure of the aptamer molecule according to its pI value and, thus, the reversing of the direction of the response (ΔRct) by the pH change was also discussed. The level of PSA secreted from PCa cells was investigated using impedimetric transduction. The specificity of the aptasensor was validated through selectivity studies against non-specific tumor markers like VEGF and different cancer cell lines including breast cancer and androgen-insensitive prostate cancer. The developed system showcases a label-free, fast, specific, and cost-effective approach for PSA detection, highlighting the importance of medium pH and the electrostatic environment on the aptamer's response. Our work emphasizes the potential for such aptasensors in clinical diagnostics and paves the way for further exploration into using transition metal oxides in biosensing applications.

Droplet bouncing electricity generation on graphene substrate

Abstract Since the discovery of the phenomenon of droplets bouncing on hydrophobic surfaces, researchers have been dedicated to studying the underlying physical mechanisms of this phenomenon. Particularly, in recent years, researchers have focused on the observation that droplet bouncing can generate electrical signals. Inspired by this, we explore the potential applications of electrical signals generated by droplets (water droplets) bouncing in sensors and other relevant fields. In this study, we chose a well-established reduced graphene oxide (rGO) film, typical in the sensor field, as a substrate to investigate the bouncing electricity generation performance of water droplets on it. Three variable factors were considered, including droplet bouncing on rGO substrates with different inclinations, bouncing of droplets of different sizes at the same inclination on rGO substrates, and droplet dropping frequency, to investigate their effects on the electrical signals.

Investigating on the Tribological Behavior of Binderless WC Matrix Composite

The purpose of this study was to investigate the dry friction and wear behavior of WC-4.3wt.%MgO-2wt.%ZrO2 (WM2Z) composite. WM2Z composite prepared by high-energy ball milling and spark plasma sintering (SPS) technology exhibited excellent comprehensive mechanical properties and dense microstructure. Dry friction test results indicated that the increase of sliding speed will lead to the decrease of friction coefficient, while at the same sliding speed, the extension of sliding time has no significant effect on the friction coefficient. The wear volume increased proportionally with the sliding time, while the wear rate stabilized after reaching a certain duration. The wear mechanism was mainly slight abrasive wear. Additionally, some oxidation occurred on both the WM2Z composite and the Si3N4 ball during friction, forming an oxide film that contributed to the reduction of the friction coefficient. The novelty of this study lies in the first systematic investigation of the effects of sliding speed and time on the wear performance of WM2Z composite, and the revelation that in high-speed sliding environments, even with shorter sliding times, the material experiences faster wear. This discovery emphasizes the important role of sliding speed in the wear process and provides new insights into understanding the wear mechanism of materials in practical applications. This study not only enriches the friction and wear theory of binderless WC matrix composites, but also provides important experimental data and theoretical support for the design and application of related materials, laying a solid foundation for wear resistance optimization and industrial applications.

Clarifying the Relationship Between Chemical States of P in Fe–P Alloys and Pitting Corrosion Resistance

Fe–0.002 P, Fe–0.05 P, Fe–0.2 P, and Fe–2 P alloys (numbers indicate the mass%) were fabricated, and their pitting potentials, depassivation pH values, and active dissolution rates were measured. The order of pitting potentials was (high) Fe–0.002 P ≥ Fe–0.05 P ≥ Fe–0.2 P ≫ Fe–2 P (low), and that of depassivation pH values was (low) Fe–0.002 P ≤ Fe–0.05 P ≤ Fe–0.2 P ≪ Fe–2 P (high). Both parameters changed significantly between the Fe–0.2 P and Fe–2 P alloys. No evidence of grain boundary segregation of P was observed in the Fe–0.05 P alloy. In the Fe–0.2 P alloy, grain boundary segregation of P was observed, but no pitting occurred at the grain boundaries. In the Fe–2 P alloy, Fe3P precipitated at the grain boundaries and in grains, but pitting corrosion occurred in the alloy matrix and not in Fe3P. This indicated that P in the solid solution was the main cause of the decrease in pitting corrosion resistance. The P concentration in the surface oxide film on Fe–2 P was higher than that on Fe–0.2 P, and the P in the films was determined to be FePO4. The decrease in the pitting resistance with an increasing P concentration was due to FePO4.

Influence of Temperature on the Performance of Metal Semiconductor Metal Photodetector Fabricated by Pure and Cationic Doped (Mg2+ and Cu2+) SnO2 Nanoparticles

Research based on various temperatures always provides beneficial awareness in the fabrication of a vital photodetector for significant applications. Increasing temperature and including dopants in photodetector materials will influence the functioning of the photodetector. This study included the influence of temperature on pure and doped SnO2 photodetectors. The crystal structure of stannic oxide has been modified by adding cationic dopants, namely Mg2+ and Cu2+, through co-precipitation techniques. Various characterization techniques were employed to examine the impact of Mg2+ and Cu2+ on the Sn4+ lattice. The electrical properties of the materials were studied at different temperatures using the Hall effect. Pure SnO2, Mg-doped SnO2, and Cu-doped SnO2 nanoparticles were synthesised separately and used as photodetectors using fluorine-doped tin oxide film as a conductive medium. The fabricated photodetectors are optimized by current-voltage characteristics at different temperatures. The effects of defects in crystal structure, oxygen vacancies, carrier concentration, and temperature on the photodetectors were studied. Comparative studies of pure and doped SnO2 photodetectors revealed that temperature and crystal defects play a significant role in photoconduction.

Improving microstructure and frictional wear behavior of plasma cladding FeCoCrNiMo high-entropy alloy layers by annealing treatment

The application of high-strength, wear-resistant materials for the restoration of large-scale coal development equipment is pivotal in ensuring efficient production and energy conservation within the industry. In this study, FeCoCrNiMo high-entropy alloy (HEA) cladding layers were fabricated on Q235 steel using plasma cladding techniques and subsequently subjected to annealing at 700°C, 800°C, 900°C, and 1000°C, respectively. The microstructural evolution, hardness, and wear resistance of the annealed cladding layers were thoroughly investigated. The results indicated that the microstructure of FeCoCrNiMo HEAs predominantly consisted of alternating eutectic formations of FCC, σ, and μ phases. The content of σ phase initially increased and then decreased with the increase of the annealing temperature. As the σ phase increased, both the microhardness and wear resistance were enhanced. Compared to HEA layers annealed at other temperatures, the HEA layer annealed at 900°C exhibited the highest hardness (700 HV). The wear mechanisms of the cladding layers were predominantly characterized by oxidative wear and adhesive wear. Notably, a stable oxide film was observed on the surface of the cladding layer treated at 900°C, with a wear rate as low as 1.27×10-7mm3N-1mm-1. This study provided a technological basis and theoretical support for the repair of coal equipment.

Enhanced accident tolerance properties of AlCrCuFeMoNbx high entropy coating for nuclear fuel cladding

High entropy alloy AlCrCuFeMoNbx (x=0.5, 0.8, 1.4, 2.0) coatings were deposited on Zr-1Nb alloy substrates by magnetron co-sputtering to improve the accident tolerance capability of the nuclear fuel cladding. The structural and accidental tolerant properties of high-entropy alloy coatings have been investigated comprehensively. The results show that coatings with varying Nb contents exhibit amorphous structures. The hardness and elastic modulus of the coatings increase with the Nb content, reaching their maximum values at x = 2.0, which are 11.38GPa and 186.05GPa, respectively. In both the simulated normal operating and accident environment of the nuclear fuel cladding, the oxidation resistance of the coating has been investigated. The best oxidation resistance was achieved at x=0.8 in pure water at 360℃under 18.6MPa for 3 days. The dense Cr2O3 and CrNbO4 oxide films generated on the surface hinder the diffusion of oxygen ions, and account for the lower weight gain 5.10mg/dm2, decreased by 56.4% compared to that of the uncoated zirconium alloy. The coating with x=0.5 showed a drastic reduction in oxidized weight gain by 84.02% compared to the uncoated zirconium alloy in water steam at 1200℃, demonstrating excellent accident tolerance, which is due to the dense α-Al2O3 and CrNbO4 protective layer generated on the surface of the coating. These findings suggest that high entropy alloy coatings have promising accidental tolerance capabilities for nuclear fuel cladding.

Process optimization of wet etching for split gate trench MOSFET

Abstract In this paper, the influence of etching technology on the performance of Split Gate Trench (SGT) MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor) is studied, and the significance and contribution of these improvements in the fields of mechatronics, robotics and control systems are discussed. Etching can be categorized into wet etching and dry etching, with wet etching being widely used for etching the gates of SGT MOSFETs. Due to the isotropic nature of wet etching, issues such as undercutting, trenching, and insufficient link-up region length can arise, leading to short circuits between the gate and the source. The improvement of this problem directly promotes the enhancement of mechatronics system efficiency, the improvement of robot dynamic performance and accuracy, and the realization of efficient control strategies in control systems. By optimizing the process flow to enhance the adhesion of photoresist, increase the density of the HDP (High Density Plasma) deposited oxide film, and adjust the etching rate and frequency of wet etching, it is possible to mitigate the issues of isotropy and insufficient precision in wet etching. These improvements address failure phenomena and enhance product yield.

Structural and morphological properties of CeO2 films deposited by radio frequency magnetron sputtering for back-end-of-line integration

Cerium oxides have potential applications ranging from low-temperature gas sensing to photodetection. A back-end-of-line integration of the material into complementary metal-oxide-semiconductor device fabrication processes has many advantages but places limits on material deposition, most notably the thermal budget for deposition and annealing. Here, we investigate thin cerium oxide films deposited by radio frequency (RF) magnetron sputtering at substrate temperatures of 300°C and RF magnetron powers between 30 W and 70 W without any post-deposition annealing steps. Our investigation of the structural and morphological properties reveals a columnar texture of the thin films, and we find that the material is composed predominantly of CeO2 (111), with a large degree of crystallinity. We discuss implications for resistive gas sensing applications.

A design of green slurry for copper/cobalt barrier-step chemical mechanical polishing with controlled removal selectivity and dynamic galvanic corrosion inhibition

Chemical mechanical polishing (CMP) is one critical process in chip fabrication while also regarded as highly polluting due to the toxic CMP slurries. Though green slurries were recently proposed and developed, few of them could satisfy the stringent requirements of the simultaneous planarization of copper/cobalt heterogeneous structure, especially in technology node below 14 nm. In this contribution, a green CMP slurry with a biodegradable chelator methylglycinediacetic acid (MGDA) and a plant-extract inhibitor disproportionated rosin (DR) was designed. Nanometer-scale smooth surface, removal selectivity, galvanic corrosion inhibition and residual control was realized with the developed slurry. Through comprehensive experiments and theoretical calculations, the roles of the ingredients played and their synergistic material removal mechanism were elucidated. MGDA partially dissolved the oxide film, especially Cu(OH)2 formed by H2O2 and the porous film could be more easily removed by the mechanical friction of abrasive particles. DR ensured post-polished surface quality by inhibiting over-corrosion through adsorption on copper surface. Density-functional-theory calculations analyzed DR's molecular reactivity and determined the most stable parallel adsorption configuration. The work provides useful insights into the fundamental interactions of components in CMP process. In addition, both MGDA and DR are commercially available with low cost, showing great practical application prospect in low-technology-node chip fabrication.