Pub Date : 2026-01-30DOI: 10.1016/j.surfcoat.2026.133247
Jing Luan , Zijun Cao , Hongying Lu , Songtao Dong , Lei Wang , Takayuki Tokoroyama , Hongbo Ju
The multi-lubricant synergistic strategy is widely recognized as one of the most effective approaches for developing solid self-lubricant materials to replace conventional oil- or grease-based lubricant systems. This study employed RF magnetron sputtering to dope Ag into an optimized ZrN–MoSN system, with the aim of enhancing its tribological performance. Ag incorporation induced nanoscale structural heterogeneity within the film, resulting in a multiphase architecture comprising face-centered cubic (fcc) ZrN, fccAg, Mo–S–N species (hexagonal close-packed (hcp) MoS2, amorphous Mo(SN)ₓ, and MoS₂(N₂), and Ag–S-based compounds). Although Ag addition reduced the mechanical strength of the film, it markedly enhanced its self-lubricant capacity at both room temperature (RT) and elevated temperatures (500 °C). Tribological performance is driven by synergistic lubrication of multiple tribo-phases. At room temperature, the film contains MoS₂, MoO₃, and Ag₂Mo₂O₇, which transform at elevated temperatures into an oxide-dominated assemblage, primarily Ag₂MoO₄, revealing the temperature-dependent evolution of the tribo-phase. However, the trade-off between friction reduction and wear resistance persists, primarily owing to reduced hardness and the formation of mechanically fragile tribo-layers.
多润滑剂协同策略被广泛认为是开发固体自润滑材料以取代传统油基或脂基润滑系统的最有效方法之一。本研究采用射频磁控溅射技术将Ag掺杂到优化的ZrN-MoSN体系中，以提高其摩擦学性能。Ag的掺入诱导了薄膜内部纳米级结构的非均质性，形成了由面心立方（fcc） ZrN、fccAg、Mo - s - N(六方密排（hcp） MoS2、无定形Mo（SN）ₓ、MoS₂（N₂）和Ag基化合物组成的多相结构。Ag的加入虽然降低了膜的机械强度，但在室温（RT）和高温（500℃）下，它都显著提高了膜的自润滑能力。摩擦学性能是由多个摩擦相的协同润滑驱动的。在室温下，薄膜含有MoS₂，MoO₃和Ag₂Mo₂O₇，它们在高温下转化为氧化物主导的组合，主要是Ag₂MoO₄，揭示了摩擦相的温度依赖演化。然而，摩擦减少和耐磨性之间的权衡仍然存在，主要是由于硬度降低和机械脆性摩擦层的形成。
{"title":"Silver-enhanced ZrN-MoSN composite films via magnetron sputtering: Insighting into the microstructure and optimizing self-lubricating properties","authors":"Jing Luan , Zijun Cao , Hongying Lu , Songtao Dong , Lei Wang , Takayuki Tokoroyama , Hongbo Ju","doi":"10.1016/j.surfcoat.2026.133247","DOIUrl":"10.1016/j.surfcoat.2026.133247","url":null,"abstract":"<div><div>The multi-lubricant synergistic strategy is widely recognized as one of the most effective approaches for developing solid self-lubricant materials to replace conventional oil- or grease-based lubricant systems. This study employed RF magnetron sputtering to dope Ag into an optimized ZrN–MoSN system, with the aim of enhancing its tribological performance. Ag incorporation induced nanoscale structural heterogeneity within the film, resulting in a multiphase architecture comprising face-centered cubic (fcc) ZrN, fcc<img>Ag, Mo–S–N species (hexagonal close-packed (hcp) MoS<sub>2</sub>, amorphous Mo(SN)ₓ, and MoS₂(N₂), and Ag–S-based compounds). Although Ag addition reduced the mechanical strength of the film, it markedly enhanced its self-lubricant capacity at both room temperature (RT) and elevated temperatures (500 °C). Tribological performance is driven by synergistic lubrication of multiple tribo-phases. At room temperature, the film contains MoS₂, MoO₃, and Ag₂Mo₂O₇, which transform at elevated temperatures into an oxide-dominated assemblage, primarily Ag₂MoO₄, revealing the temperature-dependent evolution of the tribo-phase. However, the trade-off between friction reduction and wear resistance persists, primarily owing to reduced hardness and the formation of mechanically fragile tribo-layers.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133247"},"PeriodicalIF":6.1,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098622","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 : 2026-01-29DOI: 10.1016/j.surfcoat.2026.133240
Rong Ma , Tingchen Du , Xueling Fan , Xiaolong Gao , Jiachen Qian , Weihai Li
The thermal cycling behavior and failure mechanism of Yb2Si2O7 environmental barrier coatings (EBCs) deposited by plasma spray-physical vapor deposition were investigated after 1000 cycles of exposure in dry air at 1350 °C and 1250 °C. A damage quantification method based on interfacial damage was developed to characterize the degradation of EBCs. The results revealed that thermal cycling induced the formation of pores in the top coat (TC) and bond coat (BC) layers as well as in the interface regions. The thermally grown oxide (TGO) layer at the interface progressively thickened, leading to the initiation of vertical cracks, followed by delamination at the TGO/BC interface. The damage caused by thermal cycling was significantly more severe than that induced by isothermal oxidation, with localized delamination observed after only 800 cycles. Interfacial delamination was the primary mode of thermal cycling damage. Frequent temperature fluctuations resulted in oxidation instability, manifested by the formation of TGO layers with distinct color contrasts. Furthermore, a damage constitutive model was established based on the degradation of critical spallation resistance and thermoelastic theory. The damage quantification theory was validated, as evidenced by the prediction of damage evolution and the corresponding delamination failure in room-temperature compression tests after thermal cycling. The damage evolution followed a power-law function of the number of cycles, providing a valuable reference for the quantitative assessment of EBCs damage.
{"title":"Thermal cycling failure mechanism and damage quantification of PS-PVD sprayed Yb2Si2O7 environmental barrier coating","authors":"Rong Ma , Tingchen Du , Xueling Fan , Xiaolong Gao , Jiachen Qian , Weihai Li","doi":"10.1016/j.surfcoat.2026.133240","DOIUrl":"10.1016/j.surfcoat.2026.133240","url":null,"abstract":"<div><div>The thermal cycling behavior and failure mechanism of Yb<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> environmental barrier coatings (EBCs) deposited by plasma spray-physical vapor deposition were investigated after 1000 cycles of exposure in dry air at 1350 °C and 1250 °C. A damage quantification method based on interfacial damage was developed to characterize the degradation of EBCs. The results revealed that thermal cycling induced the formation of pores in the top coat (TC) and bond coat (BC) layers as well as in the interface regions. The thermally grown oxide (TGO) layer at the interface progressively thickened, leading to the initiation of vertical cracks, followed by delamination at the TGO/BC interface. The damage caused by thermal cycling was significantly more severe than that induced by isothermal oxidation, with localized delamination observed after only 800 cycles. Interfacial delamination was the primary mode of thermal cycling damage. Frequent temperature fluctuations resulted in oxidation instability, manifested by the formation of TGO layers with distinct color contrasts. Furthermore, a damage constitutive model was established based on the degradation of critical spallation resistance and thermoelastic theory. The damage quantification theory was validated, as evidenced by the prediction of damage evolution and the corresponding delamination failure in room-temperature compression tests after thermal cycling. The damage evolution followed a power-law function of the number of cycles, providing a valuable reference for the quantitative assessment of EBCs damage.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133240"},"PeriodicalIF":6.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098690","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 : 2026-01-29DOI: 10.1016/j.surfcoat.2026.133242
Yan Zhang , Ying Wang , Ningbo Hu , Lin Liu , Xiaobing Zhao , Yuanyuan Zhu , Ningyi Yuan , Jianning Ding
Poor corrosion resistance and susceptibility to ice accumulation at low temperature significantly limit the application of magnesium (Mg) alloy. It is crucial to develop a durable coating that offers long-term anti-corrosion and anti-icing/deicing properties for the protection of Mg alloy. In this study, a LDH (layered double hydroxide)-PDMS (polydimethylsiloxane)/SO (dimethyl silicone oil) smooth coating with multiple protection function was successfully constructed on the surface of Mg alloy substrate based on the three-level cooperative protection mechanism of “dynamic lubrication layer-static barrier layer-nano oil storage unit”. The combined action of PDMS and LDH could form a robust barrier to passively block corrosive media. The SO would form a dynamic lubrication layer at the surface to provide lubrication and dynamic barrier ability. The LDH could also act as the nano oil storage for SO to ensure the stability of lubrication layer. The final coating system showed excellent comprehensive properties such as long-term corrosion protection, anti-icing/deicing, hydrophobicity, self-cleaning and excellent mechanical stability. Due to the excellent barrier effect of the composite coating, it could still provide excellent corrosion protection after immersion in 3.5 wt% NaCl solution for 35 days. After 210 abrasion cycles and 320 tape-peeling cycles, respectively, the surface retained remarkably low ice adhesion strength (τice < 20 kPa), demonstrating its exceptional mechanical durability. In addition, the LDH-PDMS/SO coating showed good anti-icing/deicing performance at −18 °C, outstanding adhesion (5B grade) and self-cleaning properties, and had great application potential in long-term anti-corrosion and anti-icing protection of Mg alloy.
{"title":"A sturdy PDMS-based multifunctional smooth coating with long-term corrosion resistance, anti-icing/deicing durability and self-cleaning performance","authors":"Yan Zhang , Ying Wang , Ningbo Hu , Lin Liu , Xiaobing Zhao , Yuanyuan Zhu , Ningyi Yuan , Jianning Ding","doi":"10.1016/j.surfcoat.2026.133242","DOIUrl":"10.1016/j.surfcoat.2026.133242","url":null,"abstract":"<div><div>Poor corrosion resistance and susceptibility to ice accumulation at low temperature significantly limit the application of magnesium (Mg) alloy. It is crucial to develop a durable coating that offers long-term anti-corrosion and anti-icing/deicing properties for the protection of Mg alloy. In this study, a LDH (layered double hydroxide)-PDMS (polydimethylsiloxane)/SO (dimethyl silicone oil) smooth coating with multiple protection function was successfully constructed on the surface of Mg alloy substrate based on the three-level cooperative protection mechanism of “dynamic lubrication layer-static barrier layer-nano oil storage unit”. The combined action of PDMS and LDH could form a robust barrier to passively block corrosive media. The SO would form a dynamic lubrication layer at the surface to provide lubrication and dynamic barrier ability. The LDH could also act as the nano oil storage for SO to ensure the stability of lubrication layer. The final coating system showed excellent comprehensive properties such as long-term corrosion protection, anti-icing/deicing, hydrophobicity, self-cleaning and excellent mechanical stability. Due to the excellent barrier effect of the composite coating, it could still provide excellent corrosion protection after immersion in 3.5 wt% NaCl solution for 35 days. After 210 abrasion cycles and 320 tape-peeling cycles, respectively, the surface retained remarkably low ice adhesion strength (τ<sub>ice</sub> < 20 kPa), demonstrating its exceptional mechanical durability. In addition, the LDH-PDMS/SO coating showed good anti-icing/deicing performance at −18 °C, outstanding adhesion (5B grade) and self-cleaning properties, and had great application potential in long-term anti-corrosion and anti-icing protection of Mg alloy.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"523 ","pages":"Article 133242"},"PeriodicalIF":6.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090264","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 : 2026-01-29DOI: 10.1016/j.surfcoat.2026.133222
Erik Calvo-García , Cristiano S. Abreu , Óscar Barro , Felipe Arias-González , Antonio Riveiro , Rafael Comesaña , Manuel Román , Salvador Pérez-Betanzos , Fernando Lusquiños , José R. Gomes , Juan Pou
Laser microtexturing is a promising technique to enhance the limited durability of forging tools by generating reservoirs capable of trapping lubricant particles, thus reducing friction even under hot working conditions. This work aims to evaluate the effects of laser microtexturing variables on the surface properties and wear resistance of AISI H13 hot forging tool steel. For the first time, the application of laser microtexturing treatments was performed on H13 steel in three heat treatment conditions: annealing without subsequent heat treatment, quenching and tempering, and nitriding after quenching and tempering. The effects of laser intensity, scanning speed, pitch, and number of passes on roughness, hardness, and wettability were analysed for each heat treatment condition. Roughness increased when using higher laser intensity and number of passes, or lower scanning speed, whereas the surface hardness was barely altered by laser treatments. Moreover, the treatments that produced higher roughness improved surface wettability for forging lubricants, and the grooves generated through laser treatments effectively retained graphite particles from hot forging lubricants, which is expected to be beneficial for the tribological behaviour of hot forging tools. Wear tests in a lubricant medium at room temperature revealed that treatments with lower heat inputs and larger pitches led to reduced mass losses. Finally, the major novelty of this work is the development, for the first time, of ring compression tests on laser-microtextured tools to evaluate friction under hot forging conditions. These tests revealed a clear decrease in the coefficient of friction in textured samples compared to non-textured ones, especially when using higher scanning speeds or larger pitches. Overall, this work provides new insights into improving the tribological performance of hot forging tools through laser microtexturing treatments.
{"title":"Effects of laser microtexturing on the surface properties and tribological behaviour of hot forging tool steels","authors":"Erik Calvo-García , Cristiano S. Abreu , Óscar Barro , Felipe Arias-González , Antonio Riveiro , Rafael Comesaña , Manuel Román , Salvador Pérez-Betanzos , Fernando Lusquiños , José R. Gomes , Juan Pou","doi":"10.1016/j.surfcoat.2026.133222","DOIUrl":"10.1016/j.surfcoat.2026.133222","url":null,"abstract":"<div><div>Laser microtexturing is a promising technique to enhance the limited durability of forging tools by generating reservoirs capable of trapping lubricant particles, thus reducing friction even under hot working conditions. This work aims to evaluate the effects of laser microtexturing variables on the surface properties and wear resistance of AISI H13 hot forging tool steel. For the first time, the application of laser microtexturing treatments was performed on H13 steel in three heat treatment conditions: annealing without subsequent heat treatment, quenching and tempering, and nitriding after quenching and tempering. The effects of laser intensity, scanning speed, pitch, and number of passes on roughness, hardness, and wettability were analysed for each heat treatment condition. Roughness increased when using higher laser intensity and number of passes, or lower scanning speed, whereas the surface hardness was barely altered by laser treatments. Moreover, the treatments that produced higher roughness improved surface wettability for forging lubricants, and the grooves generated through laser treatments effectively retained graphite particles from hot forging lubricants, which is expected to be beneficial for the tribological behaviour of hot forging tools. Wear tests in a lubricant medium at room temperature revealed that treatments with lower heat inputs and larger pitches led to reduced mass losses. Finally, the major novelty of this work is the development, for the first time, of ring compression tests on laser-microtextured tools to evaluate friction under hot forging conditions. These tests revealed a clear decrease in the coefficient of friction in textured samples compared to non-textured ones, especially when using higher scanning speeds or larger pitches. Overall, this work provides new insights into improving the tribological performance of hot forging tools through laser microtexturing treatments.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"523 ","pages":"Article 133222"},"PeriodicalIF":6.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090265","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 : 2026-01-29DOI: 10.1016/j.surfcoat.2026.133243
Qingkai Chu , Huimin Liu , Chujunwen Lu , Qinghao Sun , Julin Wang
In this study, the corrosion behaviour of Monel 400 with and without a MoS2 lubricating coating was comparatively analysed through electrochemical and salt spray corrosion experiments, alongside multiple characterization techniques. The coated samples exhibited significantly accelerated corrosion, with a 2.3-fold increase in corrosion rate during salt spray testing and a rise in corrosion current density from 0.49 μA·cm−2 to 1.15 μA·cm−2. Electrochemical impedance spectroscopy showed an 81.9% reduction in charge transfer resistance. The deterioration mechanism involves several interconnected processes: the MoS2 coating promotes anodic dissolution while suppressing the formation of the protective passivation film (Cu2O/Ni(OH)2). XPS analysis revealed a corresponding increase in non-protective corrosion products, with the CuO/Cu2O ratio rising from 0.47 to 0.86 and the NiCl2/Ni(OH)2 ratio from 0.40 to 0.68. The porous structure of the coating facilitated the adsorption and transport of corrosive media (Cl−, H2O, O2), leading to an increase in non-protective corrosion products (CuO/NiCl2). Furthermore, the oxidation of MoS2 to MoO3 further disrupted the surface film and catalysed corrosion reactions. These mechanisms act synergistically, leading to a significant reduction in the corrosion resistance of Monel 400.
{"title":"Effect of MoS2 lubricating coatings on the corrosion behaviour of monel 400 alloy","authors":"Qingkai Chu , Huimin Liu , Chujunwen Lu , Qinghao Sun , Julin Wang","doi":"10.1016/j.surfcoat.2026.133243","DOIUrl":"10.1016/j.surfcoat.2026.133243","url":null,"abstract":"<div><div>In this study, the corrosion behaviour of Monel 400 with and without a MoS<sub>2</sub> lubricating coating was comparatively analysed through electrochemical and salt spray corrosion experiments, alongside multiple characterization techniques. The coated samples exhibited significantly accelerated corrosion, with a 2.3-fold increase in corrosion rate during salt spray testing and a rise in corrosion current density from 0.49 μA·cm<sup>−2</sup> to 1.15 μA·cm<sup>−2</sup>. Electrochemical impedance spectroscopy showed an 81.9% reduction in charge transfer resistance. The deterioration mechanism involves several interconnected processes: the MoS<sub>2</sub> coating promotes anodic dissolution while suppressing the formation of the protective passivation film (Cu<sub>2</sub>O/Ni(OH)<sub>2</sub>). XPS analysis revealed a corresponding increase in non-protective corrosion products, with the CuO/Cu<sub>2</sub>O ratio rising from 0.47 to 0.86 and the NiCl<sub>2</sub>/Ni(OH)<sub>2</sub> ratio from 0.40 to 0.68. The porous structure of the coating facilitated the adsorption and transport of corrosive media (Cl<sup>−</sup>, H<sub>2</sub>O, O<sub>2</sub>), leading to an increase in non-protective corrosion products (CuO/NiCl<sub>2</sub>). Furthermore, the oxidation of MoS<sub>2</sub> to MoO<sub>3</sub> further disrupted the surface film and catalysed corrosion reactions. These mechanisms act synergistically, leading to a significant reduction in the corrosion resistance of Monel 400.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"523 ","pages":"Article 133243"},"PeriodicalIF":6.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090278","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 : 2026-01-29DOI: 10.1016/j.surfcoat.2026.133246
Burak Ceper , Ozge Ozgurluk , Ibrahim Calıs , Sefa Emre Sunbul , Yasin Ozgurluk , Mehmet Masum Tuncay
Damage mechanisms such as oxidation and hot corrosion, which shorten life of the materials and system efficiency, occur in systems operating at high temperatures in the aviation, aerospace, automotive, and defense industries. In this study, Ti6Al4V and TiAlN-coated Ti6Al4V alloys, which have high specific strength and corrosion resistance, were subjected to isothermal hot corrosion tests at 900 °C in the presence of 45% Na2SO4 and 55% V2O5 hot corrosion salts for 1, 3, 5, and 10 h under open-to-atmosphere conditions. The changing phase, microstructure, and elemental distribution of the alloys were determined using advanced characterization techniques such as SEM, EDS, and XRD. Systems with a TiAlN coating layer were found to be more durable in short- and medium-term corrosive environments compared to the Ti6Al4V alloy.
{"title":"Comparison of hot corrosion behavior of Ti6Al4V and TiAlN-coated Ti6Al4V alloys in Na2SO4 -V2O5 environment","authors":"Burak Ceper , Ozge Ozgurluk , Ibrahim Calıs , Sefa Emre Sunbul , Yasin Ozgurluk , Mehmet Masum Tuncay","doi":"10.1016/j.surfcoat.2026.133246","DOIUrl":"10.1016/j.surfcoat.2026.133246","url":null,"abstract":"<div><div>Damage mechanisms such as oxidation and hot corrosion, which shorten life of the materials and system efficiency, occur in systems operating at high temperatures in the aviation, aerospace, automotive, and defense industries. In this study, Ti6Al4V and TiAlN-coated Ti6Al4V alloys, which have high specific strength and corrosion resistance, were subjected to isothermal hot corrosion tests at 900 °C in the presence of 45% Na<sub>2</sub>SO<sub>4</sub> and 55% V<sub>2</sub>O<sub>5</sub> hot corrosion salts for 1, 3, 5, and 10 h under open-to-atmosphere conditions. The changing phase, microstructure, and elemental distribution of the alloys were determined using advanced characterization techniques such as SEM, EDS, and XRD. Systems with a TiAlN coating layer were found to be more durable in short- and medium-term corrosive environments compared to the Ti6Al4V alloy.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"523 ","pages":"Article 133246"},"PeriodicalIF":6.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090139","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}
Improving the interfacial bonding between ceramic particles within NiP matrix remained a challenging task to engineers. Loosening of ceramic particle during sliding test is a common problem and has not been addressed extensively till now to the best of author's knowledge. Thus, in the present investigation TiO2 reinforced NiP coating using electroless route has been successfully done. The study investigates the influence of incorporating uncoated TiO2 particles and TiO2 particles pre-coated with NiP and Cu (core-shell structures) into electroless NiP matrix. The pre-coated particles were analysed through EDS and SEM. Both uncoated and pre-coated TiO2 were separately incorporated into the NiP matrix, and the resulting coatings were heat treated (annealing) at 400 °C. Structural and morphological characterisations were performed using SEM, EDS, and XRD, while mechanical, tribological, and electrochemical performances were systematically evaluated. Results indicated that the incorporation of pre-coated TiO2 particles enhances ceramic particle dispersion and retention within the NiP matrix, leading to modified microstructural features. Compared with conventional Ni-P-TiO2 and Ni-P-Cu-TiO2 composites, coatings containing pre-coated particles exhibited superior hardness, reduced friction and wear, and significantly improved corrosion resistance. The NiP pre-coated TiO2 matrix showed the maximum hardness of 1258 ± 22 HV. Very obviously, the same coating also showed minimum wear rate of 3.26 ± 0.22 mgN−1 m−1 in terms of mass loss and 0.000427 ± 0.0000126 cm3N−1 m−1 in terms of volume loss. On the other hand, Cu pre-coated TiO2 matrix showed the best corrosion resistance.
{"title":"Mechanical, tribological and corrosion performance of uncoated and pre-coated TiO2 particles incorporated NiP coatings","authors":"Sourav Sarkar , Supriyo Roy , Chinmaya Kumar Sahoo , Saikat Ranjan Maity","doi":"10.1016/j.surfcoat.2026.133245","DOIUrl":"10.1016/j.surfcoat.2026.133245","url":null,"abstract":"<div><div>Improving the interfacial bonding between ceramic particles within Ni<img>P matrix remained a challenging task to engineers. Loosening of ceramic particle during sliding test is a common problem and has not been addressed extensively till now to the best of author's knowledge. Thus, in the present investigation TiO<sub>2</sub> reinforced Ni<img>P coating using electroless route has been successfully done. The study investigates the influence of incorporating uncoated TiO<sub>2</sub> particles and TiO<sub>2</sub> particles pre-coated with Ni<img>P and Cu (core-shell structures) into electroless Ni<img>P matrix. The pre-coated particles were analysed through EDS and SEM. Both uncoated and pre-coated TiO<sub>2</sub> were separately incorporated into the Ni<img>P matrix, and the resulting coatings were heat treated (annealing) at 400 °C. Structural and morphological characterisations were performed using SEM, EDS, and XRD, while mechanical, tribological, and electrochemical performances were systematically evaluated. Results indicated that the incorporation of pre-coated TiO<sub>2</sub> particles enhances ceramic particle dispersion and retention within the Ni<img>P matrix, leading to modified microstructural features. Compared with conventional Ni-P-TiO<sub>2</sub> and Ni-P-Cu-TiO<sub>2</sub> composites, coatings containing pre-coated particles exhibited superior hardness, reduced friction and wear, and significantly improved corrosion resistance. The Ni<img>P pre-coated TiO<sub>2</sub> matrix showed the maximum hardness of 1258 ± 22 HV. Very obviously, the same coating also showed minimum wear rate of 3.26 ± 0.22 mgN<sup>−1</sup> m<sup>−1</sup> in terms of mass loss and 0.000427 ± 0.0000126 cm<sup>3</sup>N<sup>−1</sup> m<sup>−1</sup> in terms of volume loss. On the other hand, Cu pre-coated TiO<sub>2</sub> matrix showed the best corrosion resistance.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"523 ","pages":"Article 133245"},"PeriodicalIF":6.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090138","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 : 2026-01-27DOI: 10.1016/j.surfcoat.2026.133236
Yulin Luo , Minghao Zhang , Song Gao , Wenli Zhang , Yiwei Yu , Longchao Cao , Rong Chen
Extreme equipment has a critical need for coatings with exceptional wear resistance across a wide temperature range. Dual-functional MoS₂-SiC ceramics were innovatively incorporated into FeCoCrNi coating during laser directed energy deposition to enhance its tribological performance across a wide temperature range (RT to 800 °C). The microstructural evolution and tribological behavior over different temperature intervals were systematically investigated. Active element sulfur alters the surface tension distribution of the molten pool through the solute capillarity effect, competing with the thermocapillary-driven flow to generate an in-situ stirring effect at edge of the molten pool, leading to an increased thermal gradients (530.6 to 800.2 °C/mm) and cooling rate (1048.8 to 1604.9 °C/s), resulting in grain refinement (71.1 to 24.49 μm) and more uniform crystal orientation. The high mixing enthalpy promoted the formation of Cr3S4 particles at grain boundaries with hundreds of nanometers in scale, which played an important role in enhancing thermal stability of coating. The composite coating showed increased nanohardness (4.4 to 6.2 Gpa) and slightly reduced elastic modulus (190.6 to 181.1 Gpa), contributing to significantly enhanced tribological properties. At 600–800 °C, the enhancement was mainly due to the formation of a protective tribo-oxide layer composed of self-lubricating MoO3 and oxidation-resistant SiO2, accompanied by improved thermal stability, including the inhibition of grain coarsening in heat-affected zone and the suppression of dynamic recrystallization in thermo-mechanically affected zone. At 200–400 °C, the reduced oxidation rate and a strongly adherent oxide layer effectively suppressed adhesive wear.
{"title":"In-situ stirring and its effect on microstructure evolution and tribological performance in wide temperature induced via addition of dual-functional ceramics in laser directed energy deposition of FeCoCrNi-MoS2-SiC","authors":"Yulin Luo , Minghao Zhang , Song Gao , Wenli Zhang , Yiwei Yu , Longchao Cao , Rong Chen","doi":"10.1016/j.surfcoat.2026.133236","DOIUrl":"10.1016/j.surfcoat.2026.133236","url":null,"abstract":"<div><div>Extreme equipment has a critical need for coatings with exceptional wear resistance across a wide temperature range. Dual-functional MoS₂-SiC ceramics were innovatively incorporated into FeCoCrNi coating during laser directed energy deposition to enhance its tribological performance across a wide temperature range (RT to 800 °C). The microstructural evolution and tribological behavior over different temperature intervals were systematically investigated. Active element sulfur alters the surface tension distribution of the molten pool through the solute capillarity effect, competing with the thermocapillary-driven flow to generate an in-situ stirring effect at edge of the molten pool, leading to an increased thermal gradients (530.6 to 800.2 °C/mm) and cooling rate (1048.8 to 1604.9 °C/s), resulting in grain refinement (71.1 to 24.49 μm) and more uniform crystal orientation. The high mixing enthalpy promoted the formation of Cr<sub>3</sub>S<sub>4</sub> particles at grain boundaries with hundreds of nanometers in scale, which played an important role in enhancing thermal stability of coating. The composite coating showed increased nanohardness (4.4 to 6.2 Gpa) and slightly reduced elastic modulus (190.6 to 181.1 Gpa), contributing to significantly enhanced tribological properties. At 600–800 °C, the enhancement was mainly due to the formation of a protective tribo-oxide layer composed of self-lubricating MoO<sub>3</sub> and oxidation-resistant SiO<sub>2</sub>, accompanied by improved thermal stability, including the inhibition of grain coarsening in heat-affected zone and the suppression of dynamic recrystallization in thermo-mechanically affected zone. At 200–400 °C, the reduced oxidation rate and a strongly adherent oxide layer effectively suppressed adhesive wear.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"523 ","pages":"Article 133236"},"PeriodicalIF":6.1,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090201","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 : 2026-01-26DOI: 10.1016/j.surfcoat.2026.133228
Suxin Dong , Bo Li , Wen Li , Yizhe Cao , Linxiang Liu , Chenhui Hu , Shaodi Wang , Dongxu Hui , Wenfei Huang , Katsuyoshi Kondoh , Junko Umeda , Xin Zhang , Shengyin Zhou , Shufeng Li
For laser melting deposited (LMD) Ti-based coatings, rapid solidification of titanium melt promotes the growth of columnar grains aligned along the path of maximum heat dissipation, resulting in the dominant 〈001〉 texture of β phase and the deterioration of surface strength and fracture toughness. Pre-alloying of Ti powders enables in-situ grown nano-reinforcements which can significantly influence the solidification, microstructure and properties of LMD-composites. Here, comparative studies of mixed Ti6Al4V + TiB2 powder and Ti6Al4V-TiBw composite powder on the columnar-to-equiaxed transition and strengthening efficiency for Ti6Al4V-TiBw composite coatings fabricated by LMD were performed. By a combination of microstructural characterizations, at optimal printing condition, the microstructure of different coatings fabricated using Ti6Al4V, mixed Ti6Al4V + TiB2 powder and Ti6Al4V-TiBw composite powder displayed a clear transition from coarse columnar grain, semi-columnar, to equiaxed grains with a small portion of dendrites, respectively. With strongly pinning effect of finer TiBw, the ultimate tensile strength of Ti6Al4V-TiBw composite powder coatings increases by ∼100 MPa relative to mixed Ti6Al4V + TiB2 powder coatings, accompanied with a 2% loss of plasticity. According to fractography analysis, microcracks in the mixed Ti6Al4V + TiB₂ powder coating initiate and propagate through TiBw clusters and alloy matrix, while microcracks in the Ti6Al4V-TiBw composite powder coating initiate at the dendritic structure. More importantly, the underlying mechanism of TiBw introduction strategy on microstructural evolution of composite coating has been discussed based on the phase diagram of TiB and thermodynamics in terms of heterogenous-phase-related convection and undercooling in rapid solidification process.
{"title":"In-situ pre-alloying of Ti6Al4V composite coating fabricated by laser melting deposition: Synergistic improvement of microstructure and property","authors":"Suxin Dong , Bo Li , Wen Li , Yizhe Cao , Linxiang Liu , Chenhui Hu , Shaodi Wang , Dongxu Hui , Wenfei Huang , Katsuyoshi Kondoh , Junko Umeda , Xin Zhang , Shengyin Zhou , Shufeng Li","doi":"10.1016/j.surfcoat.2026.133228","DOIUrl":"10.1016/j.surfcoat.2026.133228","url":null,"abstract":"<div><div>For laser melting deposited (LMD) Ti-based coatings, rapid solidification of titanium melt promotes the growth of columnar grains aligned along the path of maximum heat dissipation, resulting in the dominant 〈001〉 texture of β phase and the deterioration of surface strength and fracture toughness. Pre-alloying of Ti powders enables in-situ grown nano-reinforcements which can significantly influence the solidification, microstructure and properties of LMD-composites. Here, comparative studies of mixed Ti6Al4V + TiB<sub>2</sub> powder and Ti6Al4V-TiBw composite powder on the columnar-to-equiaxed transition and strengthening efficiency for Ti6Al4V-TiBw composite coatings fabricated by LMD were performed. By a combination of microstructural characterizations, at optimal printing condition, the microstructure of different coatings fabricated using Ti6Al4V, mixed Ti6Al4V + TiB<sub>2</sub> powder and Ti6Al4V-TiBw composite powder displayed a clear transition from coarse columnar grain, semi-columnar, to equiaxed grains with a small portion of dendrites, respectively. With strongly pinning effect of finer TiBw, the ultimate tensile strength of Ti6Al4V-TiBw composite powder coatings increases by ∼100 MPa relative to mixed Ti6Al4V + TiB<sub>2</sub> powder coatings, accompanied with a 2% loss of plasticity. According to fractography analysis, microcracks in the mixed Ti6Al4V + TiB₂ powder coating initiate and propagate through TiBw clusters and alloy matrix, while microcracks in the Ti6Al4V-TiBw composite powder coating initiate at the dendritic structure. More importantly, the underlying mechanism of TiBw introduction strategy on microstructural evolution of composite coating has been discussed based on the phase diagram of Ti<img>B and thermodynamics in terms of heterogenous-phase-related convection and undercooling in rapid solidification process.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"523 ","pages":"Article 133228"},"PeriodicalIF":6.1,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090268","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 : 2026-01-26DOI: 10.1016/j.surfcoat.2026.133215
Phani Chalapaka , Lakshman Neelakantan , Rama Krishna L.
Magnesium alloys, owing to their high specific strength and low density, are promising materials for lightweight structural applications. However, their poor corrosion resistance severely restricts broader industrial use. The present study developed micro-arc oxidation (MAO) coatings on AZ91 magnesium alloy at a constant current density of 0.3 A cm−2 using silicate–KOH-based electrolytes containing K₂ZrF₆ and NaAlO₂ additives to modulate the ionic conductivity, consequently the coating voltage. The incorporation of K₂ZrF₆ promoted the in-situ formation of ZrO₂, while aluminate addition facilitated the development of hard MgAl₂O₄ and Al₂O₃ phases and stabilized the high-temperature tetragonal ZrO₂ (t-ZrO₂). The synergistic effect of these phases enhanced coating compactness, reduced microcracks, and improved hardness and corrosion resistance, particularly in thinner coatings. Potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in 3.5 wt% NaCl solution revealed that all the MAO coatings outperformed the corrosion resistance of the bare substrate. Among them, the optimized aluminate-containing electrolyte produced the most compact coating (A3–11), exhibiting approximately six orders of magnitude reduction in corrosion rate and a four-order increase in impedance relative to the bare substrate. The findings demonstrate that tailoring electrolyte composition enables the formation of dense, defect-minimized MAO coatings with superior protection performance on AZ91 magnesium alloy.
镁合金具有高比强度和低密度的特点，是一种很有前途的轻量化结构材料。然而，它们的耐腐蚀性差严重限制了其更广泛的工业应用。在0.3 a cm−2的恒流密度下，利用含有K₂ZrF₆和NaAlO₂添加剂的硅酸盐- koh基电解质调节AZ91镁合金的离子电导率，从而调节涂层电压，制备了微弧氧化（MAO）涂层。K₂ZrF₆的加入促进了ZrO₂的原位形成，而铝酸盐的加入促进了MgAl₂O₄和Al₂O₃相的形成，并稳定了高温正方ZrO₂（t-ZrO₂）。这些相的协同作用增强了涂层的致密性，减少了微裂纹，提高了硬度和耐腐蚀性，特别是在较薄的涂层中。在3.5 wt% NaCl溶液中进行电位动极化和电化学阻抗谱（EIS）分析，结果表明MAO涂层的耐蚀性能优于裸基体。其中，优化后的含铝酸盐电解质产生了最致密的涂层（A3-11），相对于裸衬底，腐蚀速率降低了约6个数量级，阻抗增加了4个数量级。研究结果表明，调整电解质成分可以在AZ91镁合金上形成致密的、缺陷最小化的MAO涂层，并具有优异的保护性能。
{"title":"Thicker the better or thinner: Addressing the dichotomy in the case of MAO coated AZ91 Mg alloy for corrosion protection","authors":"Phani Chalapaka , Lakshman Neelakantan , Rama Krishna L.","doi":"10.1016/j.surfcoat.2026.133215","DOIUrl":"10.1016/j.surfcoat.2026.133215","url":null,"abstract":"<div><div>Magnesium alloys, owing to their high specific strength and low density, are promising materials for lightweight structural applications. However, their poor corrosion resistance severely restricts broader industrial use. The present study developed micro-arc oxidation (MAO) coatings on AZ91 magnesium alloy at a constant current density of 0.3 A cm<sup>−2</sup> using silicate–KOH-based electrolytes containing K₂ZrF₆ and NaAlO₂ additives to modulate the ionic conductivity, consequently the coating voltage. The incorporation of K₂ZrF₆ promoted the in-situ formation of ZrO₂, while aluminate addition facilitated the development of hard MgAl₂O₄ and Al₂O₃ phases and stabilized the high-temperature tetragonal ZrO₂ (t-ZrO₂). The synergistic effect of these phases enhanced coating compactness, reduced microcracks, and improved hardness and corrosion resistance, particularly in thinner coatings. Potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in 3.5 wt% NaCl solution revealed that all the MAO coatings outperformed the corrosion resistance of the bare substrate. Among them, the optimized aluminate-containing electrolyte produced the most compact coating (A3–11), exhibiting approximately six orders of magnitude reduction in corrosion rate and a four-order increase in impedance relative to the bare substrate. The findings demonstrate that tailoring electrolyte composition enables the formation of dense, defect-minimized MAO coatings with superior protection performance on AZ91 magnesium alloy.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"523 ","pages":"Article 133215"},"PeriodicalIF":6.1,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090280","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}
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