Pub Date : 2026-03-15Epub 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":"2026-03-15","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 : 2026-03-15Epub Date: 2026-02-10DOI: 10.1016/j.surfcoat.2026.133267
Yihao Song , Dingyong He , Yongming Guo , Gang Ji , Zheng Zhou , Xu Wu , Xingye Guo
Atmospheric plasma-sprayed (APS) TiO₂ coating is an effective surface strengthening technique for titanium alloys. However, the limitation of the bonding strength and fracture toughness of the APS TiO₂ coating restricts its applications. This work proposed an APS-deposited heterogeneous-microstructured TiO₂ coating prepared by the nano-agglomerated (n-TiO₂) feedstock powder, which contained the partially melted (PM) nano-grains, dynamic recrystallized grains from the partially melted particles (PM-DRX), and the columnar grains. The micron-agglomerated (m-TiO₂), and fused-crushed (f-TiO₂) powders were also used as the APS feedstock for comparison. The phase composition, microstructure, and mechanical properties of the optimized n-TiO₂, m-TiO₂, and f-TiO₂ coatings were systematically evaluated. The n-TiO2 coating exhibited markedly superior mechanical properties due to the strengthening effect of the unique heterogeneous microstructure, including a high microhardness (1030 HV0.3); fracture toughness (3.23 MPa·m1/2); and especially bonding strength (46.47 MPa) that was approximately 45.18% and 33.85% higher than those of the m-TiO₂ and f-TiO₂ coatings, respectively. This finding highlighted that the APS-deposited n-TiO₂ coating had a unique heterogeneous microstructure that enhanced its mechanical properties.
{"title":"Microstructural heterogeneity and synergistic strengthening mechanisms in atmospheric plasma-sprayed nano-TiO₂ coatings","authors":"Yihao Song , Dingyong He , Yongming Guo , Gang Ji , Zheng Zhou , Xu Wu , Xingye Guo","doi":"10.1016/j.surfcoat.2026.133267","DOIUrl":"10.1016/j.surfcoat.2026.133267","url":null,"abstract":"<div><div>Atmospheric plasma-sprayed (APS) TiO₂ coating is an effective surface strengthening technique for titanium alloys. However, the limitation of the bonding strength and fracture toughness of the APS TiO₂ coating restricts its applications. This work proposed an APS-deposited heterogeneous-microstructured TiO₂ coating prepared by the nano-agglomerated (n-TiO₂) feedstock powder, which contained the partially melted (PM) nano-grains, dynamic recrystallized grains from the partially melted particles (PM-DRX), and the columnar grains. The micron-agglomerated (m-TiO₂), and fused-crushed (f-TiO₂) powders were also used as the APS feedstock for comparison. The phase composition, microstructure, and mechanical properties of the optimized n-TiO₂, m-TiO₂, and f-TiO₂ coatings were systematically evaluated. The n-TiO<sub>2</sub> coating exhibited markedly superior mechanical properties due to the strengthening effect of the unique heterogeneous microstructure, including a high microhardness (1030 HV<sub>0.3</sub>); fracture toughness (3.23 MPa·m<sup>1/2</sup>); and especially bonding strength (46.47 MPa) that was approximately 45.18% and 33.85% higher than those of the m-TiO₂ and f-TiO₂ coatings, respectively. This finding highlighted that the APS-deposited n-TiO₂ coating had a unique heterogeneous microstructure that enhanced its mechanical properties.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133267"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192151","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 : 2026-03-15Epub Date: 2026-02-03DOI: 10.1016/j.surfcoat.2026.133251
Sebastian Kanik , Izabella Ślęzak-Prochazka , Mateusz Dulski , Robert Gawecki , Daniel Wójcik , Mehdi Baghayeri , Rafał Zieliński , Wojciech Simka
Electrochemical processes on titanium and its alloys play a crucial role in the biomaterials industry. Such methods, as a plasma electrolytic oxidation (PEO) are commonly used in the process of producing a porous surface, which provides a better interaction at the bone-implant interface. Nevertheless, PEO surfaces tend to lose their hydrophilicity and bioactivity after certain amount of time. It is a phenomenon called surface ageing. By using surface-activating processes like plasma treatment, it is possible to prevent it and increase the association between the endoskeleton and implant. The main objective of that study is to quantitatively evaluate how O₂ and N₂ plasma treatments influence surface ageing, wettability, morphology, and composition of PEO-coated titanium over 14 days. The O2/N2 plasma cleaning seem to detach carbon contaminants, which made the surfaces extra hydrophilic. That modification of the coatings also made the surfaces more bioactive by enhancing the cell adhesion and proliferation. Wettability has slightly diminished with time. Nonetheless, the process of ageing has decelerated. Obtained results suggest that plasma cleaning affects positively on the surface properties, what makes the treatment worthy of further investigations. That study is one of a few, which examine the time-dependent degradation of PEO coatings after plasma treatment, providing an overview of their long-term performance.
{"title":"The role of oxygen and nitrogen plasma treatments in improving bioactivity and long-term stability of PEO-modified titanium","authors":"Sebastian Kanik , Izabella Ślęzak-Prochazka , Mateusz Dulski , Robert Gawecki , Daniel Wójcik , Mehdi Baghayeri , Rafał Zieliński , Wojciech Simka","doi":"10.1016/j.surfcoat.2026.133251","DOIUrl":"10.1016/j.surfcoat.2026.133251","url":null,"abstract":"<div><div>Electrochemical processes on titanium and its alloys play a crucial role in the biomaterials industry. Such methods, as a plasma electrolytic oxidation (PEO) are commonly used in the process of producing a porous surface, which provides a better interaction at the bone-implant interface. Nevertheless, PEO surfaces tend to lose their hydrophilicity and bioactivity after certain amount of time. It is a phenomenon called surface ageing. By using surface-activating processes like plasma treatment, it is possible to prevent it and increase the association between the endoskeleton and implant. The main objective of that study is to quantitatively evaluate how O₂ and N₂ plasma treatments influence surface ageing, wettability, morphology, and composition of PEO-coated titanium over 14 days. The O<sub>2</sub>/N<sub>2</sub> plasma cleaning seem to detach carbon contaminants, which made the surfaces extra hydrophilic. That modification of the coatings also made the surfaces more bioactive by enhancing the cell adhesion and proliferation. Wettability has slightly diminished with time. Nonetheless, the process of ageing has decelerated. Obtained results suggest that plasma cleaning affects positively on the surface properties, what makes the treatment worthy of further investigations. That study is one of a few, which examine the time-dependent degradation of PEO coatings after plasma treatment, providing an overview of their long-term performance.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133251"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192265","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}
The development of AlTiN- and AlCrN-based multilayer hard coatings offers significant potential for improving performance in extreme environments. This study evaluates the effect of chromium molybdenum nitride (CrMoN) on the thermal stability and oxidation resistance of an AlTiNbSiN/AlCrBN coating deposited by cathodic arc evaporation. The crystallinity of the film was determined by grazing incidence X-ray diffraction (GIXRD), and its microstructural features were analyzed using field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). Mechanical properties were examined using a Rockwell indentation tester for adhesion strength evaluation and a nanoindentation tester for assessing hardness and elastic modulus. The results demonstrated that both the AlTiNbSiN/AlCrBN and AlTiNbSiN/AlCrBN/CrMoN coatings exhibited high thermal stabilities, maintaining a hardness of about 30 GPa even after annealing at 900 °C. XRD and TEM analyses showed that, after high-temperature vacuum annealing at 900 °C for up to 8 h, the multilayer AlTiNbSiN/AlCrBN/CrMoN coating exhibited only limited grain growth. Additional phases, such as h-AlN and h-Cr₂N, were also observed following the annealing process. With respect to oxidation resistance, the oxide layer thickness of the multilayer AlTiNbSiN/AlCrBN/CrMoN coating after oxidation at 900 °C for 8 h measured approximately 71.9 nm, whereas the AlTiNbSiN/AlCrBN film exhibited a considerably thicker oxide layer of 322.4 nm under the same conditions. The presence of a nanocrystalline, multilayer nitride structure incorporating CrMoN significantly restricted oxygen diffusion through grain boundaries within the coating. Dense Al₂O₃ and Cr₂O₃ layers, along with Si-N-O formation, effectively inhibit oxidation at elevated temperatures. As a result, the susceptibility to internal nitride oxidation was significantly reduced. These results indicate that the three-layer architecture of AlTiNbSiN/AlCrBN/CrMoN provides better oxidation resistance compared with the two-layer AlTiNbSiN/AlCrBN system. The AlTiNbSiN/AlCrBN/CrMoN coating demonstrates an excellent balance of oxidation resistance and structural stability, making it well-suited for high-temperature applications.
{"title":"Enhanced thermal stability and oxidation resistance via triple-sublayer multilayer coatings","authors":"Van-Tien Tang , Min-Xin Shi , Duc Manh Nguyen , Ke-Huan Wu , Yin-Yu Chang","doi":"10.1016/j.surfcoat.2026.133263","DOIUrl":"10.1016/j.surfcoat.2026.133263","url":null,"abstract":"<div><div>The development of AlTiN- and AlCrN-based multilayer hard coatings offers significant potential for improving performance in extreme environments. This study evaluates the effect of chromium molybdenum nitride (CrMoN) on the thermal stability and oxidation resistance of an AlTiNbSiN/AlCrBN coating deposited by cathodic arc evaporation. The crystallinity of the film was determined by grazing incidence X-ray diffraction (GIXRD), and its microstructural features were analyzed using field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). Mechanical properties were examined using a Rockwell indentation tester for adhesion strength evaluation and a nanoindentation tester for assessing hardness and elastic modulus. The results demonstrated that both the AlTiNbSiN/AlCrBN and AlTiNbSiN/AlCrBN/CrMoN coatings exhibited high thermal stabilities, maintaining a hardness of about 30 GPa even after annealing at 900 °C. XRD and TEM analyses showed that, after high-temperature vacuum annealing at 900 °C for up to 8 h, the multilayer AlTiNbSiN/AlCrBN/CrMoN coating exhibited only limited grain growth. Additional phases, such as h-AlN and h-Cr₂N, were also observed following the annealing process. With respect to oxidation resistance, the oxide layer thickness of the multilayer AlTiNbSiN/AlCrBN/CrMoN coating after oxidation at 900 °C for 8 h measured approximately 71.9 nm, whereas the AlTiNbSiN/AlCrBN film exhibited a considerably thicker oxide layer of 322.4 nm under the same conditions. The presence of a nanocrystalline, multilayer nitride structure incorporating CrMoN significantly restricted oxygen diffusion through grain boundaries within the coating. Dense Al₂O₃ and Cr₂O₃ layers, along with Si-N-O formation, effectively inhibit oxidation at elevated temperatures. As a result, the susceptibility to internal nitride oxidation was significantly reduced. These results indicate that the three-layer architecture of AlTiNbSiN/AlCrBN/CrMoN provides better oxidation resistance compared with the two-layer AlTiNbSiN/AlCrBN system. The AlTiNbSiN/AlCrBN/CrMoN coating demonstrates an excellent balance of oxidation resistance and structural stability, making it well-suited for high-temperature applications.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133263"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192264","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 : 2026-03-15Epub Date: 2026-02-06DOI: 10.1016/j.surfcoat.2026.133274
Yiqun Tang , Liang Qin , Weijie Pan , Zhuo Yang , Xiaobing Li
A central challenge in low-power laser cladding for surface engineering is to achieve coating densification and high performance under limited heat input, which often leads to insufficient molten pool dynamics. This study systematically investigated the mechanisms by which rare earth oxide CeO₂ (0–4 wt%) regulates the microstructure and tribological properties of a cobalt-based coating deposited on 40Cr steel under strictly low-power conditions (500–700 W). The results indicate that 600 W provides an optimal balance between dilution and fusion quality, and that CeO2 addition shows a pronounced threshold effect. When the CeO2 content is ≤2.0 wt%, CeO₂ promotes grain refinement by providing effective heterogeneous nucleation sites and enhancing constitutional supercooling, thereby driving a microstructural transition from coarse columnar grains to fine equiaxed dendrites. Accordingly, the microhardness increases to 587.41 HV and the coefficient of friction decreases to 0.271. Mechanistic analysis reveals that the confined Marangoni convection, characteristic of low-power processing, exacerbates the agglomeration of nanoparticles when the CeO₂ content exceeds the 2.0 wt% threshold, which in turn causes dendrite coarsening and performance degradation. The wear volume of the optimized coating (2.0 wt% CeO₂) decreases to 1.7952 mm3, which is attributed to the synergistic strengthening effects of grain refinement and grain-boundary purification. This work establishes a well-defined process window for the low-energy surface modification of thermally sensitive components.
{"title":"Threshold effect and synergistic enhancement of wear resistance in CeO₂-modified Co-based coatings fabricated via low-power laser cladding","authors":"Yiqun Tang , Liang Qin , Weijie Pan , Zhuo Yang , Xiaobing Li","doi":"10.1016/j.surfcoat.2026.133274","DOIUrl":"10.1016/j.surfcoat.2026.133274","url":null,"abstract":"<div><div>A central challenge in low-power laser cladding for surface engineering is to achieve coating densification and high performance under limited heat input, which often leads to insufficient molten pool dynamics. This study systematically investigated the mechanisms by which rare earth oxide CeO₂ (0–4 wt%) regulates the microstructure and tribological properties of a cobalt-based coating deposited on 40Cr steel under strictly low-power conditions (500–700 W). The results indicate that 600 W provides an optimal balance between dilution and fusion quality, and that CeO2 addition shows a pronounced threshold effect. When the CeO2 content is ≤2.0 wt%, CeO₂ promotes grain refinement by providing effective heterogeneous nucleation sites and enhancing constitutional supercooling, thereby driving a microstructural transition from coarse columnar grains to fine equiaxed dendrites. Accordingly, the microhardness increases to 587.41 HV and the coefficient of friction decreases to 0.271. Mechanistic analysis reveals that the confined Marangoni convection, characteristic of low-power processing, exacerbates the agglomeration of nanoparticles when the CeO₂ content exceeds the 2.0 wt% threshold, which in turn causes dendrite coarsening and performance degradation. The wear volume of the optimized coating (2.0 wt% CeO₂) decreases to 1.7952 mm<sup>3</sup>, which is attributed to the synergistic strengthening effects of grain refinement and grain-boundary purification. This work establishes a well-defined process window for the low-energy surface modification of thermally sensitive components.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133274"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192261","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 : 2026-03-15Epub Date: 2026-02-03DOI: 10.1016/j.surfcoat.2026.133253
Mahavir Singh , G. Sivakumar , Krishna N. Jonnalagadda
This work investigated the high-temperature thermomechanical behavior of thermal barrier coatings (TBCs), with a focus on failure mechanisms critical for ensuring thermal resistance and reliability under extreme conditions. High-resolution, in situ tensile and thermal expansion experiments were conducted on freestanding 8 wt% Yttria-Stabilized Zirconia (8YSZ) coatings of two different thicknesses, deposited using air plasma spray method, over a temperature range of up to 800 °C. Using custom designed infrared heat sources, fast heating rate up to 200 °C/s was achieved, with uniform temperature over the region of interest. Simultaneous thermal and dual-speed optical imaging were performed, to measure temperature distribution, full-field deformation and track crack nucleation and growth. The coefficient of thermal expansion (CTE) measured with contact free measurements was found to be 12.25 × 10−6°C−1 for thin coatings and 13.0 × 10−6°C−1 for thick coatings in the temperature range of 300–800 °C. The modulus of 8YSZ coatings increased with temperature from 8.3 GPa to 11.7 GPa and from 6.6 GPa to 8.0 GPa, for thin and thick coatings, respectively. The uniaxial tension behavior was non-linear at room and high temperatures with three different stages. Further, sintering at high temperature particularly extended the first stage. At 800 °C, it was found that thermal softening effect was minor compared to sintering and high temperatures increased both strength and stiffness. Finally, the failure was different for thick and thin coatings, with heterogeneous and gradual failure in thick coatings, compared to through-thickness cracks causing sudden failure in thin coatings.
{"title":"Tensile and thermal properties of freestanding APS-8YSZ coatings at high temperatures","authors":"Mahavir Singh , G. Sivakumar , Krishna N. Jonnalagadda","doi":"10.1016/j.surfcoat.2026.133253","DOIUrl":"10.1016/j.surfcoat.2026.133253","url":null,"abstract":"<div><div>This work investigated the high-temperature thermomechanical behavior of thermal barrier coatings (TBCs), with a focus on failure mechanisms critical for ensuring thermal resistance and reliability under extreme conditions. High-resolution, in situ tensile and thermal expansion experiments were conducted on freestanding 8 wt% Yttria-Stabilized Zirconia (8YSZ) coatings of two different thicknesses, deposited using air plasma spray method, over a temperature range of up to 800 °C. Using custom designed infrared heat sources, fast heating rate up to 200 °C/s was achieved, with uniform temperature over the region of interest. Simultaneous thermal and dual-speed optical imaging were performed, to measure temperature distribution, full-field deformation and track crack nucleation and growth. The coefficient of thermal expansion (CTE) measured with contact free measurements was found to be 12.25 × 10<sup>−6</sup> <sup>°C−1</sup> for thin coatings and 13.0 × 10<sup>−6</sup> <sup>°C−1</sup> for thick coatings in the temperature range of 300–800 °C. The modulus of 8YSZ coatings increased with temperature from 8.3 GPa to 11.7 GPa and from 6.6 GPa to 8.0 GPa, for thin and thick coatings, respectively. The uniaxial tension behavior was non-linear at room and high temperatures with three different stages. Further, sintering at high temperature particularly extended the first stage. At 800 °C, it was found that thermal softening effect was minor compared to sintering and high temperatures increased both strength and stiffness. Finally, the failure was different for thick and thin coatings, with heterogeneous and gradual failure in thick coatings, compared to through-thickness cracks causing sudden failure in thin coatings.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133253"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191801","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 : 2026-03-15Epub Date: 2026-02-04DOI: 10.1016/j.surfcoat.2026.133264
Xiao Luo , Yixin Zhao , Xin Yang , Jia Sun , Qizhong Huang
SiC-coated C/C composites were successively sprayed with (Zr0.25Hf0.25Ti0.25Ta0.25)C-30SiC coating and (Zr0.25Hf0.25Ti0.25Ta0.25)C coating to form SiC gradient composite coatings from inner layer to outer layer. After ablation above 2100 °C for 90 s, the Rl and Rm of multilayer (Zr0.25Hf0.25Ti0.25Ta0.25)C/(Zr0.25Hf0.25Ti0.25Ta0.25)C-30SiC coatings are −1.22 μm·s−1 and −0.636 mg·s−1, respectively. The excellent ablation property is attributed to the phase evolution of SiC and high entropy carbides during ablation, which forms a four-layer oxide structure with synergistic effects. The diffusion of SiC from (Zr0.25Hf0.25Ti0.25Ta0.25)C-30SiC middle layer to oxide layer is guided by sublimation, recrystallization and active oxidation. As SiO2 diffuses into the ablation layer-II, it favors improving the viscosity of the (Ti/Ta)Ox enrichment areas formed by reversible peritectic transformation of (Zr,Hf)6Ta2O17 and Zr(Hf)TiO4, effectively maintaining the stability of the interface between the ablative and oxide layers.
{"title":"Effect of SiC gradient structure on ablation resistance of (Zr0.25Hf0.25Ti0.25Ta0.25)C multilayer coatings for C/C composites","authors":"Xiao Luo , Yixin Zhao , Xin Yang , Jia Sun , Qizhong Huang","doi":"10.1016/j.surfcoat.2026.133264","DOIUrl":"10.1016/j.surfcoat.2026.133264","url":null,"abstract":"<div><div>SiC-coated C/C composites were successively sprayed with (Zr<sub>0.25</sub>Hf<sub>0.25</sub>Ti<sub>0.25</sub>Ta<sub>0.25</sub>)C-30SiC coating and (Zr<sub>0.25</sub>Hf<sub>0.25</sub>Ti<sub>0.25</sub>Ta<sub>0.25</sub>)C coating to form SiC gradient composite coatings from inner layer to outer layer. After ablation above 2100 °C for 90 s, the R<sub>l</sub> and R<sub>m</sub> of multilayer (Zr<sub>0.25</sub>Hf<sub>0.25</sub>Ti<sub>0.25</sub>Ta<sub>0.25</sub>)C/(Zr<sub>0.25</sub>Hf<sub>0.25</sub>Ti<sub>0.25</sub>Ta<sub>0.25</sub>)C-30SiC coatings are −1.22 μm·s<sup>−1</sup> and −0.636 mg·s<sup>−1</sup>, respectively. The excellent ablation property is attributed to the phase evolution of SiC and high entropy carbides during ablation, which forms a four-layer oxide structure with synergistic effects. The diffusion of SiC from (Zr<sub>0.25</sub>Hf<sub>0.25</sub>Ti<sub>0.25</sub>Ta<sub>0.25</sub>)C-30SiC middle layer to oxide layer is guided by sublimation, recrystallization and active oxidation. As SiO<sub>2</sub> diffuses into the ablation layer-II, it favors improving the viscosity of the (Ti/Ta)Ox enrichment areas formed by reversible peritectic transformation of (Zr,Hf)<sub>6</sub>Ta<sub>2</sub>O<sub>17</sub> and Zr(<em>Hf</em>)TiO<sub>4</sub>, effectively maintaining the stability of the interface between the ablative and oxide layers.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133264"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192266","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 : 2026-03-15Epub Date: 2026-02-05DOI: 10.1016/j.surfcoat.2026.133273
Runze Wei , Junhong Jia , Rui Deng , Dongqing Guo , Jian Wang , Jie Yang , Leping Cai , Yun Shi , Zongyu Zhang
To address the temperature limitations of MAX phase and improve the temperature adaptability of Ni-based coating, a NiCrAlY-Ti3AlC2-SnBiAg-Mo composite coating was fabricated via atmospheric plasma spraying. The tribological properties of the composite coating were evaluated over a wide temperature range from room temperature (RT) to 800 °C using reciprocating friction testing, and its wear mechanism was comprehensively analyzed through scanning electron microscope (SEM), X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS). Results demonstrate that SnBiAg incorporation effectively enhances coating density, reduces porosity, enhances structural homogeneity, and refines grain size. At RT, SnBiAg alloy flows into cracks along with the sliding of friction pairs, exhibiting a certain degree of crack healing capability. The composite coating (20 wt% SnBiAg) exhibited optimal wear resistance with the wear rate 1.5 × 10−5 mm3/(N·m) at 600 °C, and its thermal cycling tribological performance was the relative best. This is primarily attributed to the synergistic lubrication effect of MAX phases, various binary metal oxides, and a small amount of high-temperature lubricating phases such as NiMoO4, Ag2MoO4, and Bi2MoO6. Meanwhile, the SnBiAg-Mo alloy effectively suppresses the oxidative decomposition of Ti3AlC2 at high temperature, which results in the transformation of the primary Ti oxide from TiO2 to Ti2O3 with enhanced interlayer bonding strength.
{"title":"Tribological performance of NiCrAlY-Ti3AlC2-SnBiAg-Mo coatings over wide-temperature ranges: MAX phase stabilization at 800 °C","authors":"Runze Wei , Junhong Jia , Rui Deng , Dongqing Guo , Jian Wang , Jie Yang , Leping Cai , Yun Shi , Zongyu Zhang","doi":"10.1016/j.surfcoat.2026.133273","DOIUrl":"10.1016/j.surfcoat.2026.133273","url":null,"abstract":"<div><div>To address the temperature limitations of MAX phase and improve the temperature adaptability of Ni-based coating, a NiCrAlY-Ti<sub>3</sub>AlC<sub>2</sub>-SnBiAg-Mo composite coating was fabricated via atmospheric plasma spraying. The tribological properties of the composite coating were evaluated over a wide temperature range from room temperature (RT) to 800 °C using reciprocating friction testing, and its wear mechanism was comprehensively analyzed through scanning electron microscope (SEM), X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS). Results demonstrate that SnBiAg incorporation effectively enhances coating density, reduces porosity, enhances structural homogeneity, and refines grain size. At RT, SnBiAg alloy flows into cracks along with the sliding of friction pairs, exhibiting a certain degree of crack healing capability. The composite coating (20 wt% SnBiAg) exhibited optimal wear resistance with the wear rate 1.5 × 10<sup>−5</sup> mm<sup>3</sup>/(N·m) at 600 °C, and its thermal cycling tribological performance was the relative best. This is primarily attributed to the synergistic lubrication effect of MAX phases, various binary metal oxides, and a small amount of high-temperature lubricating phases such as NiMoO<sub>4</sub>, Ag<sub>2</sub>MoO<sub>4</sub>, and Bi<sub>2</sub>MoO<sub>6</sub>. Meanwhile, the SnBiAg-Mo alloy effectively suppresses the oxidative decomposition of Ti<sub>3</sub>AlC<sub>2</sub> at high temperature, which results in the transformation of the primary Ti oxide from TiO<sub>2</sub> to Ti<sub>2</sub>O<sub>3</sub> with enhanced interlayer bonding strength.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133273"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191806","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 : 2026-03-15Epub Date: 2026-02-10DOI: 10.1016/j.surfcoat.2026.133278
Kai Yang , Lihua Li , Wentao Peng , Lihong Fu , Shaolong Wang , Hongfei Chen , Yizhaotong Ai , Fuxin Wang , Yanfeng Gao
Atmospheric plasma-sprayed (APS) Al₂O₃-YAG amorphous coatings show potential for corrosion protection in third-generation Concentrated Solar Power (Gen3 CSP) systems but suffer from inherent porosity, microcracks, and high-temperature structural instability. To overcome these limitations, this study utilizes a laser remelting (LR) post-treatment strategy to transform the amorphous precursor into a dense, layered eutectic/amorphous composite structure. This unique architecture achieves a synergistic combination of high hardness, superior creep resistance, and damage tolerance. The remelted surface layer exhibits a peak hardness of 23.46 GPa (approximately 2.7 times that of the amorphous base) and a reduction in steady-state creep rate by nearly 65%. Mechanistically, the in-situ formed fine eutectic network acts as a barrier to dislocation motion and diffusion, significantly enhancing creep resistance. Furthermore, the dense phase boundaries promote toughening mechanisms such as crack deflection and bridging, replacing the catastrophic shear band failure of the amorphous phase with a controlled energy dissipation mode. These results demonstrate that laser-remelted Al₂O₃-YAG coatings offer a robust solution for ensuring long-term structural integrity and reliability in extreme molten salt environments.
{"title":"Achieving a synergistic combination of high hardness, enhanced creep resistance and damage tolerance in plasma-sprayed eutectic/amorphous Al₂O₃-YAG composite coatings through laser remelting","authors":"Kai Yang , Lihua Li , Wentao Peng , Lihong Fu , Shaolong Wang , Hongfei Chen , Yizhaotong Ai , Fuxin Wang , Yanfeng Gao","doi":"10.1016/j.surfcoat.2026.133278","DOIUrl":"10.1016/j.surfcoat.2026.133278","url":null,"abstract":"<div><div>Atmospheric plasma-sprayed (APS) Al₂O₃-YAG amorphous coatings show potential for corrosion protection in third-generation Concentrated Solar Power (Gen3 CSP) systems but suffer from inherent porosity, microcracks, and high-temperature structural instability. To overcome these limitations, this study utilizes a laser remelting (LR) post-treatment strategy to transform the amorphous precursor into a dense, layered eutectic/amorphous composite structure. This unique architecture achieves a synergistic combination of high hardness, superior creep resistance, and damage tolerance. The remelted surface layer exhibits a peak hardness of 23.46 GPa (approximately 2.7 times that of the amorphous base) and a reduction in steady-state creep rate by nearly 65%. Mechanistically, the in-situ formed fine eutectic network acts as a barrier to dislocation motion and diffusion, significantly enhancing creep resistance. Furthermore, the dense phase boundaries promote toughening mechanisms such as crack deflection and bridging, replacing the catastrophic shear band failure of the amorphous phase with a controlled energy dissipation mode. These results demonstrate that laser-remelted Al₂O₃-YAG coatings offer a robust solution for ensuring long-term structural integrity and reliability in extreme molten salt environments.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133278"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192152","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 : 2026-03-15Epub Date: 2026-02-04DOI: 10.1016/j.surfcoat.2026.133238
Kun Yue , Xuan Chen , Lin Wang , Meng Liu , Quan Xu , Furen Qin , Zhijun Wang , Changlin Yang , Zheng Chen
Laser cladding was employed to fabricate AlCrFeNiTix (x = 0, 0.25, 0.5, 0.75, and 1) high-entropy alloy (HEA) coatings on Q235 steel substrates. The study systematically investigated the influence of Ti content on the phase composition, microstructure, and mechanical properties of the coatings. With increasing Ti content, the phase composition of the coatings transitioned from a BCC + B2 dual-phase structure to a BCC + B2 + L21 multiphase system. Ti addition promoted the formation of the L21 phase and induced a unique sunflower-like microstructure, characterized by L21 phase embedding within the sunflower structure. This microstructural evolution significantly enhanced the hardness and wear resistance of the coatings. The AlCrFeNiTi coating (x = 1) exhibited the highest microhardness of 750 HV, while the AlCrFeNiTi0.5 coating showed the highest wear resistance with a wear volume of only 0.004 mm3, which is an order of magnitude lower than that of the Ti-free coating (0.034 mm3) However, excessive Ti content led to increased brittleness due to the growth of the L21 phase, resulting in a gradual decline in wear performance.
{"title":"Enhancing mechanical properties of AlCrFeNiTix high-entropy alloy coatings via Ti-induced sunflower microstructure","authors":"Kun Yue , Xuan Chen , Lin Wang , Meng Liu , Quan Xu , Furen Qin , Zhijun Wang , Changlin Yang , Zheng Chen","doi":"10.1016/j.surfcoat.2026.133238","DOIUrl":"10.1016/j.surfcoat.2026.133238","url":null,"abstract":"<div><div>Laser cladding was employed to fabricate AlCrFeNiTi<sub>x</sub> (x = 0, 0.25, 0.5, 0.75, and 1) high-entropy alloy (HEA) coatings on Q235 steel substrates. The study systematically investigated the influence of Ti content on the phase composition, microstructure, and mechanical properties of the coatings. With increasing Ti content, the phase composition of the coatings transitioned from a BCC + B2 dual-phase structure to a BCC + B2 + L2<sub>1</sub> multiphase system. Ti addition promoted the formation of the L2<sub>1</sub> phase and induced a unique sunflower-like microstructure, characterized by L2<sub>1</sub> phase embedding within the sunflower structure. This microstructural evolution significantly enhanced the hardness and wear resistance of the coatings. The AlCrFeNiTi coating (x = 1) exhibited the highest microhardness of 750 HV, while the AlCrFeNiTi<sub>0.5</sub> coating showed the highest wear resistance with a wear volume of only 0.004 mm<sup>3</sup>, which is an order of magnitude lower than that of the Ti-free coating (0.034 mm<sup>3</sup>) However, excessive Ti content led to increased brittleness due to the growth of the L2<sub>1</sub> phase, resulting in a gradual decline in wear performance.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"524 ","pages":"Article 133238"},"PeriodicalIF":6.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191805","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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