Pub Date : 2025-02-26DOI: 10.1016/j.surfcoat.2025.131981
K. Tanaka , H. Kindlund , S. Kodambaka
In an effort to understand the mechanisms leading to van der Waals epitaxy, using plan-view transmission electron microscopy and diffraction, we compare and contrast the microstructures of ultra-thin (≈ 9 nm) Ta2C layers sputter-deposited simultaneously on graphene and 8-nm-thick, amorphous silicon nitride (a-SiNx) membranes supported by holey transmission electron microscopy grids. On both graphene and a-SiNx membranes, we obtain polycrystalline trigonal -Ta2C layers with similar grain sizes. However, the Ta2C layers deposited on graphene exhibit an in-plane orientation relationship: ||. Our results reveal that the onset of epitaxy can be observed even on one-atom-thick crystals.
{"title":"Enhanced crystallinity in Ta2C thin films grown on free-standing graphene","authors":"K. Tanaka , H. Kindlund , S. Kodambaka","doi":"10.1016/j.surfcoat.2025.131981","DOIUrl":"10.1016/j.surfcoat.2025.131981","url":null,"abstract":"<div><div>In an effort to understand the mechanisms leading to van der Waals epitaxy, using plan-view transmission electron microscopy and diffraction, we compare and contrast the microstructures of ultra-thin (≈ 9 nm) Ta<sub>2</sub>C layers sputter-deposited simultaneously on graphene and 8-nm-thick, amorphous silicon nitride (a-SiN<sub><em>x</em></sub>) membranes supported by holey transmission electron microscopy grids. On both graphene and a-SiN<sub><em>x</em></sub> membranes, we obtain polycrystalline trigonal <span><math><mi>α</mi></math></span>-Ta<sub>2</sub>C layers with similar grain sizes. However, the Ta<sub>2</sub>C layers deposited on graphene exhibit an in-plane orientation relationship: <span><math><msub><mfenced><mrow><mn>2</mn><mover><mn>1</mn><mo>¯</mo></mover><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn></mrow></mfenced><mrow><msub><mi>Ta</mi><mn>2</mn></msub><mi>C</mi></mrow></msub></math></span>||<span><math><msub><mfenced><mrow><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn></mrow></mfenced><mtext>graphene</mtext></msub></math></span>. Our results reveal that the onset of epitaxy can be observed even on one-atom-thick crystals.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131981"},"PeriodicalIF":5.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Producing coatings of repeatable quality is a crucial objective of any coating process, including atmospheric thermal spraying (APS). With the existing output regulation methods used in APS, it is common to see significant variations in the coating characteristics of sequentially coated parts, which are insufficient to meet the ever-stricter requirements of new coating applications. Therefore, this paper suggests a novel process output regulation method that improves repeatability of coating characteristics by combining advanced monitoring solutions and machine learning approaches. It uses Gaussian process models and Kalman filters to adjust process input parameters between sequentially coated parts based on feedback of gun voltage, ensemble particles' temperatures, deposition efficiency, and application rate. The method enables not only compensation of process degradation but more generally minimizes the long-term differences in the process state between different coating runs by using a system-state-aware process model to track the temporal changes of the coating system. The developed method was tested in an industrial environment and compared to the most commonly used approach in APS of spraying sequential parts with the same process input parameters, and to the approach of adjusting the process inputs based on the gun voltage. The developed method produced coatings with smaller variation and closer to the target compared to the other two approaches.
{"title":"Improving coating repeatability by parameter adaptation through process monitoring, Gaussian process models and Kalman filters","authors":"Uroš Hudomalj , Xavier Guidetti , Lukas Weiss , Majid Nabavi , Konrad Wegener","doi":"10.1016/j.surfcoat.2025.131976","DOIUrl":"10.1016/j.surfcoat.2025.131976","url":null,"abstract":"<div><div>Producing coatings of repeatable quality is a crucial objective of any coating process, including atmospheric thermal spraying (APS). With the existing output regulation methods used in APS, it is common to see significant variations in the coating characteristics of sequentially coated parts, which are insufficient to meet the ever-stricter requirements of new coating applications. Therefore, this paper suggests a novel process output regulation method that improves repeatability of coating characteristics by combining advanced monitoring solutions and machine learning approaches. It uses Gaussian process models and Kalman filters to adjust process input parameters between sequentially coated parts based on feedback of gun voltage, ensemble particles' temperatures, deposition efficiency, and application rate. The method enables not only compensation of process degradation but more generally minimizes the long-term differences in the process state between different coating runs by using a system-state-aware process model to track the temporal changes of the coating system. The developed method was tested in an industrial environment and compared to the most commonly used approach in APS of spraying sequential parts with the same process input parameters, and to the approach of adjusting the process inputs based on the gun voltage. The developed method produced coatings with smaller variation and closer to the target compared to the other two approaches.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131976"},"PeriodicalIF":5.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-26DOI: 10.1016/j.surfcoat.2025.131980
Saeed M. Jafarpour , Andreas Leineweber , Matthew Bolan , Anke Dalke , Horst Biermann
The current study addresses one of the most important challenges during thermochemical diffusion treatment of austenitic stainless steel with different surface finishing conditions, namely the necessary surface de-passivation initiated by different types of in-situ surface activations. Therefore, the effectiveness of three types of in-situ surface activations applied to polished and to ground surfaces followed by an identical afterglow plasma nitrocarburizing treatment were conducted on AISI 316L austenitic stainless steel. Utilizing a recently developed modified hot-wall reactor with a separately plasma-activated electrode, flexible treatment design with different surface activation types was enabled. Accordingly, treatments were conducted by applying the plasma at an electrode made of graphite bars as well as an electrode made of steel bars with methane addition. Besides, the reactor was further equipped with a laser-based absorption spectroscopy sensor for real-time monitoring and measurement of the gas composition resulting from the discharge at the electrodes during surface treatments. The effectiveness of each applied surface activation combined with a subsequent plasma nitrocarburizing treatment was then evaluated based on the nitrogen and carbon composition-depth profiles. The results highlight that the effectiveness of a surface activation depends on the nature of the applied activation in correlation with the samples' surface finishing conditions. It is revealed that polished surfaces can be activated more effectively than ground surfaces by applying the same activation method.
{"title":"Effectiveness of surface activation induced by different methods during afterglow plasma nitrocarburizing of AISI 316L","authors":"Saeed M. Jafarpour , Andreas Leineweber , Matthew Bolan , Anke Dalke , Horst Biermann","doi":"10.1016/j.surfcoat.2025.131980","DOIUrl":"10.1016/j.surfcoat.2025.131980","url":null,"abstract":"<div><div>The current study addresses one of the most important challenges during thermochemical diffusion treatment of austenitic stainless steel with different surface finishing conditions, namely the necessary surface de-passivation initiated by different types of in-situ surface activations. Therefore, the effectiveness of three types of in-situ surface activations applied to <em>polished</em> and to <em>ground</em> surfaces followed by an identical afterglow plasma nitrocarburizing treatment were conducted on AISI 316L austenitic stainless steel. Utilizing a recently developed modified hot-wall reactor with a separately plasma-activated electrode, flexible treatment design with different surface activation types was enabled. Accordingly, treatments were conducted by applying the plasma at an electrode made of graphite bars as well as an electrode made of steel bars with methane addition. Besides, the reactor was further equipped with a laser-based absorption spectroscopy sensor for real-time monitoring and measurement of the gas composition resulting from the discharge at the electrodes during surface treatments. The effectiveness of each applied surface activation combined with a subsequent plasma nitrocarburizing treatment was then evaluated based on the nitrogen and carbon composition-depth profiles. The results highlight that the effectiveness of a surface activation depends on the nature of the applied activation in correlation with the samples' surface finishing conditions. It is revealed that <em>polished</em> surfaces can be activated more effectively than <em>ground</em> surfaces by applying the same activation method.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131980"},"PeriodicalIF":5.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-26DOI: 10.1016/j.surfcoat.2025.131961
Heng Tao , Zhaohui Wang , Xuming Wu , Lincong Li , Yihan Wang , Chenchen Zhao , Wenbo Du
In this study, the oxidation behavior and mechanism of AlxCoCrFeNi1.5Ti0.1 (x = 0, 0.25, 0.5, 0.75, 1.0) high-entropy alloy (HEA) coatings at high temperatures ranging from 700 °C to 900 °C were investigated. The microstructure and oxidation products of the HEA coatings were characterized with scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). In order to elucidate the effect of Al content on the oxidation behavior of HEA coatings, a novel oxidation kinetic model modified by Al content was developed. The results indicate that the oxidation weight gain of the HEA coatings generally follows a parabolic law. With the increase of Al content, the microstructure of HEA coatings transforms into a dual-phase structure (FCC and BCC) containing new BCC phases. When the HEA coatings are composed of the dual-phase structure (FCC and BCC), the oxidation process of the coatings is primarily inhibited by the diffusion of Al and Cr within the oxide layer, and the oxidation rate of the coatings is significantly reduced. The oxide layer of HEA coatings mainly comprises an inner Al2O3 layer and an outer Cr2O3 layer.
{"title":"Effect of Al content on high-temperature oxidation behavior and mechanism of AlxCoCrFeNi1.5Ti0.1 high-entropy alloy coatings by laser cladding","authors":"Heng Tao , Zhaohui Wang , Xuming Wu , Lincong Li , Yihan Wang , Chenchen Zhao , Wenbo Du","doi":"10.1016/j.surfcoat.2025.131961","DOIUrl":"10.1016/j.surfcoat.2025.131961","url":null,"abstract":"<div><div>In this study, the oxidation behavior and mechanism of Al<sub>x</sub>CoCrFeNi<sub>1.5</sub>Ti<sub>0.1</sub> (x = 0, 0.25, 0.5, 0.75, 1.0) high-entropy alloy (HEA) coatings at high temperatures ranging from 700 °C to 900 °C were investigated. The microstructure and oxidation products of the HEA coatings were characterized with scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). In order to elucidate the effect of Al content on the oxidation behavior of HEA coatings, a novel oxidation kinetic model modified by Al content was developed. The results indicate that the oxidation weight gain of the HEA coatings generally follows a parabolic law. With the increase of Al content, the microstructure of HEA coatings transforms into a dual-phase structure (FCC and BCC) containing new BCC phases. When the HEA coatings are composed of the dual-phase structure (FCC and BCC), the oxidation process of the coatings is primarily inhibited by the diffusion of Al and Cr within the oxide layer, and the oxidation rate of the coatings is significantly reduced. The oxide layer of HEA coatings mainly comprises an inner Al<sub>2</sub>O<sub>3</sub> layer and an outer Cr<sub>2</sub>O<sub>3</sub> layer.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131961"},"PeriodicalIF":5.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-26DOI: 10.1016/j.surfcoat.2025.131938
G. Savorianakis , C. Rousseau , Y. Battie , A. En Naciri , B. Maes , M. Voué , S. Konstantinidis
In this study, we explore the optical and thermochromic properties of monoclinic vanadium dioxide (VO2) nanostructures, which undergo a reversible phase transition from an insulating to a metallic state at around 68 °. This phase transition is crucial for applications such as photonic devices, tunable optical filters, and energy-efficient windows. While the performance of VO2 can be optimized by tailoring its nanostructure and film morphology, to the best of our knowledge, no prior work in the literature has successfully synthesized VO2 nanostructures with well-defined morphology and high VO2 purity using the Glancing Angle Deposition (GLAD) technique.
In this work, by combining reactive magnetron sputtering of a vanadium target in an Argon-Oxygen atmosphere with GLancing Angle Deposition (GLAD), we synthesized thin films of VO2, followed by post-deposition annealing in an oxygen-rich environment. Through GLAD we elaborate anisotropic nanostructures, including tilted and straight columns morphologies. Optical characterizations techniques, such as ellipsometric measurements and grazing incidence X-ray diffraction (GIXRD), were employed to evaluate the crystalline phase and dielectric functions of the films in both their metallic and insulating states. For the tilted nanocolumns, azimuthal Mueller matrix measurements reveal pronounced anisotropic effects. Optical transmission studies show that nanostructured films, particularly those with pillar morphologies, display superior thermochromic performance, with increased transmission, enhanced infrared modulation, and broader hysteresis compared to dense films. The influence of nanostructure porosity on the optical response is also confirmed through simulations using both COMSOL and the Berreman matrix methods, which demonstrate strong agreement in reflectivity predictions. Our work represents a significant advancement in the synthesis of well-defined VO2 nanostructures, opening new pathways for optimizing the material properties for advanced optical and thermochromic applications.
{"title":"Optical anisotropy of nanostructured vanadium dioxide thermochromic thin films synthesized by reactive magnetron sputtering combined with glancing angle deposition","authors":"G. Savorianakis , C. Rousseau , Y. Battie , A. En Naciri , B. Maes , M. Voué , S. Konstantinidis","doi":"10.1016/j.surfcoat.2025.131938","DOIUrl":"10.1016/j.surfcoat.2025.131938","url":null,"abstract":"<div><div>In this study, we explore the optical and thermochromic properties of monoclinic vanadium dioxide (VO<sub>2</sub>) nanostructures, which undergo a reversible phase transition from an insulating to a metallic state at around 68 °<span><math><mi>C</mi></math></span>. This phase transition is crucial for applications such as photonic devices, tunable optical filters, and energy-efficient windows. While the performance of VO<sub>2</sub> can be optimized by tailoring its nanostructure and film morphology, to the best of our knowledge, no prior work in the literature has successfully synthesized VO<sub>2</sub> nanostructures with well-defined morphology and high VO<sub>2</sub> purity using the Glancing Angle Deposition (GLAD) technique.</div><div>In this work, by combining reactive magnetron sputtering of a vanadium target in an Argon-Oxygen atmosphere with GLancing Angle Deposition (GLAD), we synthesized thin films of VO<sub>2</sub>, followed by post-deposition annealing in an oxygen-rich environment. Through GLAD we elaborate anisotropic nanostructures, including tilted and straight columns morphologies. Optical characterizations techniques, such as ellipsometric measurements and grazing incidence X-ray diffraction (GIXRD), were employed to evaluate the crystalline phase and dielectric functions of the films in both their metallic and insulating states. For the tilted nanocolumns, azimuthal Mueller matrix measurements reveal pronounced anisotropic effects. Optical transmission studies show that nanostructured films, particularly those with pillar morphologies, display superior thermochromic performance, with increased transmission, enhanced infrared modulation, and broader hysteresis compared to dense films. The influence of nanostructure porosity on the optical response is also confirmed through simulations using both COMSOL and the Berreman matrix methods, which demonstrate strong agreement in reflectivity predictions. Our work represents a significant advancement in the synthesis of well-defined VO<sub>2</sub> nanostructures, opening new pathways for optimizing the material properties for advanced optical and thermochromic applications.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131938"},"PeriodicalIF":5.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Precise determination of particle velocity remains a tremendous challenge of simulating the shot peening process, and it significantly influences the accuracy of residual stress and surface roughness. To overcome these bottlenecks, this paper proposed a novel model that integrates computational fluid dynamics (CFD) with the discrete element method (DEM) for determining the velocity of particles in the shot peening process. Shot peening fluid phase (compressed air) and solid phase (particle) were described by Navier-Stokes equations and Newton's second law, respectively. The calculation of particles velocity was achieved through the coupling of momentum exchange between the fluid and solid phases. The relative error of particle velocity is less than 12 % through the particle velocity measurement experiment. The results show that upon traversing the expansion section of the nozzle, particles experience a substantial enhancement in acceleration capability, resulting in a considerable increase in velocity. Consequently, the design of the nozzle must take into account the profound effect of its structure on particle velocity. Further, particle velocity was incorporated into the finite element model (FEM) of shot peening for spiral bevel gears. Drawing on the residual stress and surface topography, the feasibility of CFD-DEM model was further corroborated. The significance of this paper lies in its contribution to the simulation of shot peening for complex curved components, thereby advancing the field of numerical simulation in shot peening.
{"title":"A fluid-solid coupled model for particle velocity and validation in spiral bevel gear shot peening","authors":"Liangliang Lv, Jiuyue Zhao, Wen Shao, Xin Li, Zhaokang Zhou, Jinyuan Tang, Hao Wu","doi":"10.1016/j.surfcoat.2025.131977","DOIUrl":"10.1016/j.surfcoat.2025.131977","url":null,"abstract":"<div><div>Precise determination of particle velocity remains a tremendous challenge of simulating the shot peening process, and it significantly influences the accuracy of residual stress and surface roughness. To overcome these bottlenecks, this paper proposed a novel model that integrates computational fluid dynamics (CFD) with the discrete element method (DEM) for determining the velocity of particles in the shot peening process. Shot peening fluid phase (compressed air) and solid phase (particle) were described by Navier-Stokes equations and Newton's second law, respectively. The calculation of particles velocity was achieved through the coupling of momentum exchange between the fluid and solid phases. The relative error of particle velocity is less than 12 % through the particle velocity measurement experiment. The results show that upon traversing the expansion section of the nozzle, particles experience a substantial enhancement in acceleration capability, resulting in a considerable increase in velocity. Consequently, the design of the nozzle must take into account the profound effect of its structure on particle velocity. Further, particle velocity was incorporated into the finite element model (FEM) of shot peening for spiral bevel gears. Drawing on the residual stress and surface topography, the feasibility of CFD-DEM model was further corroborated. The significance of this paper lies in its contribution to the simulation of shot peening for complex curved components, thereby advancing the field of numerical simulation in shot peening.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131977"},"PeriodicalIF":5.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-26DOI: 10.1016/j.surfcoat.2025.131974
Ramaiany C. Mesquita , Jessica B. Serra , Eden S. Silva , Samuel F. Rodrigues , Beatriz S. Batista , Luciana M.R. Alencar , Clésio C. Melo , Alan S. Menezes , Anderson O. Lobo , Fernanda R. Marciano
This manuscript investigates the optimization of nanostructured TiO2 surfaces on Ti-35Nb-5Ta alloy through electrochemical anodizing, focusing on its effects on roughness, adhesion, work function, and corrosion resistance. The objective is to enhance surface properties that influence osseointegration for biomedical applications. Microstructural analysis confirmed the presence of equiaxed β-phase grains (BCC) and amorphous TiO2 nanotubes. Atomic force microscopy (AFM) indicated a 35 % increase in surface roughness (Rq) after anodizing, which improved adhesion by 25 % due to increased surface area and reduced nanotube diameter (< 80 nm). The work function (φ) increased from 4.32 eV to 4.47 eV, associated with vacancy formation and enhanced Ti exposure. Electrochemical evaluation in simulated body fluid (SBF) electrolyte was performed to assess corrosion resistance. The anodized surface exhibited enhanced corrosion resistance, demonstrating improved passivation behavior in SBF. The combined effects of increased roughness, adhesion force, and corrosion resistance suggest that electrochemical anodizing is a viable strategy to optimize nanostructured Ti-based biomaterials, promoting better osseointegration.
{"title":"Optimization of nanostructured surfaces of the β-alloy Ti-35Nb-5Ta: The effect of electrochemical anodization on the functional performance of titanium dioxide nanotubes","authors":"Ramaiany C. Mesquita , Jessica B. Serra , Eden S. Silva , Samuel F. Rodrigues , Beatriz S. Batista , Luciana M.R. Alencar , Clésio C. Melo , Alan S. Menezes , Anderson O. Lobo , Fernanda R. Marciano","doi":"10.1016/j.surfcoat.2025.131974","DOIUrl":"10.1016/j.surfcoat.2025.131974","url":null,"abstract":"<div><div>This manuscript investigates the optimization of nanostructured TiO<sub>2</sub> surfaces on Ti-35Nb-5Ta alloy through electrochemical anodizing, focusing on its effects on roughness, adhesion, work function, and corrosion resistance. The objective is to enhance surface properties that influence osseointegration for biomedical applications. Microstructural analysis confirmed the presence of equiaxed β-phase grains (BCC) and amorphous TiO<sub>2</sub> nanotubes. Atomic force microscopy (AFM) indicated a 35 % increase in surface roughness (<em>R</em><sub><em>q</em></sub>) after anodizing, which improved adhesion by 25 % due to increased surface area and reduced nanotube diameter (< 80 nm). The work function (<em>φ</em>) increased from 4.32 eV to 4.47 eV, associated with vacancy formation and enhanced Ti exposure. Electrochemical evaluation in simulated body fluid (SBF) electrolyte was performed to assess corrosion resistance. The anodized surface exhibited enhanced corrosion resistance, demonstrating improved passivation behavior in SBF. The combined effects of increased roughness, adhesion force, and corrosion resistance suggest that electrochemical anodizing is a viable strategy to optimize nanostructured Ti-based biomaterials, promoting better osseointegration.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"503 ","pages":"Article 131974"},"PeriodicalIF":5.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.surfcoat.2025.131964
Fengyuan Bao , Feng Li , Oleg Bashkov , Zhiyuan Wang , Ling Sun
Acoustic emission monitoring was conducted on the micro-arc oxidation process of the D16AT aluminum alloy plate with double-sided rolled pure aluminum in a silicate system electrolyte. Using the t-SNE algorithm, the recorded signals were classified based on the parameters of the acoustic emission signals. The analysis examined the regularities of the micro-arc oxidation stages under different current density conditions and their correspondence with signal characteristics and categories. Further discussion was held on the passivation and film formation mechanisms during the early, middle, and late stages of micro-arc oxidation. The effective film formation process of MAO was divided into four main stages: initial stage, weak micro-arc discharge, stable micro-arc discharge, and large arc discharge. Additionally, it included five sub-stages: conventional anodizing, weak glow discharge, transition from weak to strong glow discharge, transition from strong glow discharge to weak micro-arc discharge, and weak micro-arc discharge. The transition moments of these stages can be identified and determined by the frequency distribution of AE signals. As the current density increases, the discharge mechanism undergoes stage-wise changes. At different current densities, type-a signals primarily originate from gas glow discharge, while type-b signals are caused by breakdown at the bottom of the passivation film pores. Type-c signals mainly result from stable micro-arc discharge, and the increase in type-d signals marks the transition to a penetration-type strong discharge mechanism.
{"title":"Stage division and discharge mechanism characterization of micro-arc oxidation based on acoustic emission","authors":"Fengyuan Bao , Feng Li , Oleg Bashkov , Zhiyuan Wang , Ling Sun","doi":"10.1016/j.surfcoat.2025.131964","DOIUrl":"10.1016/j.surfcoat.2025.131964","url":null,"abstract":"<div><div>Acoustic emission monitoring was conducted on the micro-arc oxidation process of the D16AT aluminum alloy plate with double-sided rolled pure aluminum in a silicate system electrolyte. Using the t-SNE algorithm, the recorded signals were classified based on the parameters of the acoustic emission signals. The analysis examined the regularities of the micro-arc oxidation stages under different current density conditions and their correspondence with signal characteristics and categories. Further discussion was held on the passivation and film formation mechanisms during the early, middle, and late stages of micro-arc oxidation. The effective film formation process of MAO was divided into four main stages: initial stage, weak micro-arc discharge, stable micro-arc discharge, and large arc discharge. Additionally, it included five sub-stages: conventional anodizing, weak glow discharge, transition from weak to strong glow discharge, transition from strong glow discharge to weak micro-arc discharge, and weak micro-arc discharge. The transition moments of these stages can be identified and determined by the frequency distribution of AE signals. As the current density increases, the discharge mechanism undergoes stage-wise changes. At different current densities, type-a signals primarily originate from gas glow discharge, while type-b signals are caused by breakdown at the bottom of the passivation film pores. Type-c signals mainly result from stable micro-arc discharge, and the increase in type-d signals marks the transition to a penetration-type strong discharge mechanism.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131964"},"PeriodicalIF":5.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.surfcoat.2025.131978
Hongxu Cheng , Hong Luo , Chunhui Fan , Xuefei Wang , Chengtao Li
The high-entropy alloy (HEA) coating offers a promising solution by combining the superior performance characteristics of bulk HEAs with cost-effectiveness, facilitating broader application potential. Magnetron sputtering is a valuable method for producing HEA coatings, but establishing the relationship between composition, processing parameters, and performance is challenging due to the complexity of alloys with five or more principal elements. This study employed machine learning techniques to accelerate the screening and design of HEA coatings with enhanced corrosion resistance. This machine learning design framework constructed a random forest prediction model by using alloy composition ratios and key magnetron sputtering process parameters as input features, pitting potential (Epit) and corrosion potential (Ecorr) as output features, followed by multi-objective optimization via genetic algorithm. A HEA coating with excellent corrosion resistance was obtained through only four iterations and experimental verification. This approach rapidly guided the selection of components and process parameters, assisting in the development of new HEA coatings. As a result, the Ti35Zr14Nb28Mo7V16 HEA coating was successfully prepared, demonstrating a pitting potential of 1931.1mVSCE and a corrosion potential of 13.8 mVSCE in 3.5 wt% NaCl solution. The passivation region (EpitEcorr, mVSCE) was enhanced by 15 %, indicating excellent corrosion resistance. The corrosion resistance mechanism was also explained by microstructural characterization and electrochemical analysis.
{"title":"Accelerated design of high-entropy alloy coatings for high corrosion resistance via machine learning","authors":"Hongxu Cheng , Hong Luo , Chunhui Fan , Xuefei Wang , Chengtao Li","doi":"10.1016/j.surfcoat.2025.131978","DOIUrl":"10.1016/j.surfcoat.2025.131978","url":null,"abstract":"<div><div>The high-entropy alloy (HEA) coating offers a promising solution by combining the superior performance characteristics of bulk HEAs with cost-effectiveness, facilitating broader application potential. Magnetron sputtering is a valuable method for producing HEA coatings, but establishing the relationship between composition, processing parameters, and performance is challenging due to the complexity of alloys with five or more principal elements. This study employed machine learning techniques to accelerate the screening and design of HEA coatings with enhanced corrosion resistance. This machine learning design framework constructed a random forest prediction model by using alloy composition ratios and key magnetron sputtering process parameters as input features, pitting potential (<em>E</em><sub>pit</sub>) and corrosion potential (<em>E</em><sub>corr</sub>) as output features, followed by multi-objective optimization via genetic algorithm. A HEA coating with excellent corrosion resistance was obtained through only four iterations and experimental verification. This approach rapidly guided the selection of components and process parameters, assisting in the development of new HEA coatings. As a result, the Ti<sub>35</sub>Zr<sub>14</sub>Nb<sub>28</sub>Mo<sub>7</sub>V<sub>16</sub> HEA coating was successfully prepared, demonstrating a pitting potential of 1931.1mV<sub>SCE</sub> and a corrosion potential of 13.8 mV<sub>SCE</sub> in 3.5 wt% NaCl solution. The passivation region (<em>E</em><sub>pit</sub><span><math><mo>−</mo></math></span><em>E</em><sub>corr</sub>, mV<sub>SCE</sub>) was enhanced by 15 %, indicating excellent corrosion resistance. The corrosion resistance mechanism was also explained by microstructural characterization and electrochemical analysis.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131978"},"PeriodicalIF":5.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.surfcoat.2025.131965
J.L. Rosales-Lopez , M. Olivares-Luna , L.E. Castillo-Vela , K.D. Chaparro-Pérez , F.P. Espino-Cortés , I. Campos-Silva
This study examines the impact of current density on the growth kinetics of boride layers during the Pulsed-DC Powder-Pack Boriding (PDCPB). It explores the combined effects of thermally activated diffusion (TD) and electromigration (EM) on boride layer growth kinetics. The analysis assesses how variations in electrical parameters and the properties of the boriding media (particularly electrical resistance and thermal phenomena influenced by components such as KBF4, B4C, and SiC) affect overall mass transfer mechanism.
Initial observations indicated a temperature increase related to the Joule effect (~100 K for the entire experimental set), which correlated with the applied current density and the resistive behavior of the semiconductor elements within the boriding media. Additionally, the B activation energies in FeB and Fe2B phases, estimated at a current density of 460 mA·cm−2, was found to be ~9 % lower compared to that at 230 mA·cm−2. A reduction of ~19 % and ~ 25 % in B activation energies for boride layer formation at 230 mA·cm−2 and 460 mA·cm−2, respectively, was noted compared to conventional boriding processes.
These findings suggest an enhancement in B diffusivity attributable to the electric field. However, while higher temperatures and current densities shorten the boride layer incubation time, differentiating the contributions of TD and EM remains a challenge.
{"title":"Insights on the Pulsed-DC Powder-Pack Boriding Process: Effect of current density and electric field implications on the FeB and Fe2B growth kinetics","authors":"J.L. Rosales-Lopez , M. Olivares-Luna , L.E. Castillo-Vela , K.D. Chaparro-Pérez , F.P. Espino-Cortés , I. Campos-Silva","doi":"10.1016/j.surfcoat.2025.131965","DOIUrl":"10.1016/j.surfcoat.2025.131965","url":null,"abstract":"<div><div>This study examines the impact of current density on the growth kinetics of boride layers during the Pulsed-DC Powder-Pack Boriding (PDCPB). It explores the combined effects of thermally activated diffusion (TD) and electromigration (EM) on boride layer growth kinetics. The analysis assesses how variations in electrical parameters and the properties of the boriding media (particularly electrical resistance and thermal phenomena influenced by components such as KBF<sub>4</sub>, B<sub>4</sub>C, and SiC) affect overall mass transfer mechanism.</div><div>Initial observations indicated a temperature increase related to the Joule effect (~100 K for the entire experimental set), which correlated with the applied current density and the resistive behavior of the semiconductor elements within the boriding media. Additionally, the B activation energies in FeB and Fe<sub>2</sub>B phases, estimated at a current density of 460 mA·cm<sup>−2</sup>, was found to be ~9 % lower compared to that at 230 mA·cm<sup>−2</sup>. A reduction of ~19 % and ~ 25 % in B activation energies for boride layer formation at 230 mA·cm<sup>−2</sup> and 460 mA·cm<sup>−2</sup>, respectively, was noted compared to conventional boriding processes.</div><div>These findings suggest an enhancement in B diffusivity attributable to the electric field. However, while higher temperatures and current densities shorten the boride layer incubation time, differentiating the contributions of TD and EM remains a challenge.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"502 ","pages":"Article 131965"},"PeriodicalIF":5.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号