Surface & Coatings Technology最新文献

{"title":"Post-processing of laser-directed energy deposited IN718 superalloys through combined heat treatment and shot peening: Microstructural evolution and wear resistance enhancement","authors":"Mengyang Li ,&nbsp;Xiaofeng Dang ,&nbsp;Lingzhi Ning ,&nbsp;Dingrui Liu ,&nbsp;Yefei Geng ,&nbsp;Fangyuan Cheng ,&nbsp;Jianyong Dong ,&nbsp;Ruiyao Liang ,&nbsp;Zeng Tian ,&nbsp;Guangni Zhou ,&nbsp;Ting Guo ,&nbsp;Yao Li","doi":"10.1016/j.surfcoat.2025.132209","DOIUrl":"10.1016/j.surfcoat.2025.132209","url":null,"abstract":"<div><div>While the laser-directed energy deposition (LDED) technique is extensively employed for repairing and fabricating complex components, LDED-fabricated IN718 superalloys parts frequently exhibit inadequate wear resistance. This study systematically investigates the combination effects of heat treatment strategies (<em>i.e.</em>, direct double aging (DA) and solution + double aging (SDA) treatments) and shot peening (SP) on the microstructural evolution and 600 °C wear performance of LDED-fabricated IN718 alloys. The aging regime promotes the complete precipitation of γ″/γ′ phases, while the prior solution treatment in the SDA process achieves concurrent dissolution of most Laves phases and partial recrystallization. SP converts surface tensile stress into compressive stress, reaching –1030.67 MPa in SDA + SP. Additionally, SP induces a work-hardened layer with a depth of ∼ 250 μm and a ∼ 500 nm thick nanograin layer at the topmost surface. The grain nanocrystallization is attributed to the simultaneous action of dislocations, twins, stacking faults, and Lomer-Cottrell (L-C) locks. The synergistic effects of grain refinement, work hardening, and γ″/γ′ precipitation collectively endow the SDA + SP sample with optimal sliding wear performance at 600 °C, exhibiting a 14.8 % reduction in average coefficient of friction and a remarkable 78.9 % decrease in wear rate compared to the as-received sample. This performance enhancement correlates with a transition in wear mechanisms to predominantly abrasive and oxidation-dominated regimes under elevated temperature conditions.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"509 ","pages":"Article 132209"},"PeriodicalIF":5.3,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882790","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}

{"title":"Effect of Si and Cr on formation of aluminide coatings on Ti6Al4V alloy by low temperature aluminizing: Wear and oxidation behavior","authors":"Kadir Mert Doleker ,&nbsp;Tuba Yener ,&nbsp;Azmi Erdogan ,&nbsp;Ferhat Yılmaz ,&nbsp;Gözde Celebi Efe","doi":"10.1016/j.surfcoat.2025.132207","DOIUrl":"10.1016/j.surfcoat.2025.132207","url":null,"abstract":"<div><div>To improve the surface properties of the Ti-6Al-4 V titanium alloy, TiAl₃-based intermetallic coatings were produced at 710 °C-4 h via a low-temperature aluminizing process. Additionally, Si and Cr were incorporated into the Ti<img>Al coating to investigate their effects on the properties of the Ti<img>Al system. The findings revealed that the coatings formed strong metallurgical bonds with the substrate, and no significant cracks were detected in the Ti<img>Al system coatings. However, the addition of Cr was found to have a negative effect on the growth of the coating layer. Similarly, the simultaneous addition of Cr and Si reduced the thickness of the layer from 14 μm to 5 μm. An increase of up to 248 GPa elastic modulus (E_IT) and 10.36 GPa hardness was achieved with the aluminide coating of Ti6Al4V, which have had 150 GPa E_IT and 5.56 GPa hardness. While all coatings provided better wear performance compared to the substrate, the lowest volume loss was observed in the TiAl coating with the highest thickness. Similarly, the best oxidation resistance was obtained in TiAl due to higher coating thickness and lower phase transformation in its coating layer compared to others. The addition of Si and Cr did not affect the formed oxide products, but they decreased the oxidation resistance due to thinner coating structure.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"509 ","pages":"Article 132207"},"PeriodicalIF":5.3,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869801","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}

{"title":"Microstructure and wear resistance of environmentally friendly NbC-FeCr coatings: An evaluation of HVOF process parameters","authors":"Lukas Tegelkamp ,&nbsp;Maximilian Grimm ,&nbsp;Susan Conze ,&nbsp;Lutz-Michael Berger ,&nbsp;Thomas Lindner ,&nbsp;Thomas Lampke","doi":"10.1016/j.surfcoat.2025.132208","DOIUrl":"10.1016/j.surfcoat.2025.132208","url":null,"abstract":"<div><div>Health risks of Co and classification of W and Co as critical raw materials are currently the driving forces behind the search for WC-Co(Cr) replacement. NbC-based hardmetal compositions have just recently emerged and are now under consideration for use as thermally sprayed wear resistant coatings. NbC is proposed to be particularly suitable for combination with Fe-based binders. In this study an agglomerated and sintered 80NbC-15Fe5Cr (wt.-%) powder was processed by means of liquid-fueled HVOF. The experiments were carried out in two series: The influence of spray distance (305 and 395 mm) and nozzle geometry (lengths of 150 and 200 mm with diameters of 11 to 14 mm) were investigated in the first series. Powder feed rate (77 to 114 g/min) and oxygen-fuel-ratio (λ = 1.0 and λ = 1.2) were varied in the second series. In-flight particle velocity of approximately 700 m/s and temperature of 2150 °C resulted in coatings of the highest quality achieved in this study. SEM and optical microscopy of the coatings showed a higher thickness with higher in-flight particle temperatures and porosities between 2.1 and 4.6 %. XRD and EDS analyses revealed the presence of oxygen as FeNb₂O₆. Strongly correlated with porosity, Vickers microhardness ranges from approximately 770 to 900 HV0.3. Unidirectional and reciprocating dry sliding wear rates of 1.2 × 10⁻⁶ and 2.1 × 10⁻⁶ mm³/(N × m), respectively are fully competitive to those of the reference coating systems WC-CoCr and Cr₃C₂-NiCr. Overall, the shorter spray distance with a smaller nozzle was advantageous when combined with λ = 1.0 and powder feed rate of 102 g/min.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"509 ","pages":"Article 132208"},"PeriodicalIF":5.3,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143898746","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}

{"title":"Microstructure and ablation behavior of a novel La2Hf2O7/ZrC-SiC/SiC graded coating for ablative protection up to 2400 °C","authors":"Dawei Wang,&nbsp;Sen Wu,&nbsp;Xin Yang,&nbsp;Xiao Luo,&nbsp;Xiaxiang Zhang,&nbsp;Qizhong Huang","doi":"10.1016/j.surfcoat.2025.132191","DOIUrl":"10.1016/j.surfcoat.2025.132191","url":null,"abstract":"<div><div>A novel La₂Hf₂O₇/ZrC-SiC/SiC graded coating with CTE increasing gradually from the inner to outside layers was prepared by pack cementation and supersonic atmospheric plasma spraying. Due to the graded multi-layer structure, the coating exhibits good ablative property after different ablation times. As ablated under 3.2 MW/m² oxygen acetylene flame for 30 and 60 s, the ablation rates are increased from −11.3 μm/s, −0.53 mg/s to 6.79 μm/s, 1.12 mg/s. The ablation results demonstrate that La₂Hf₂O₇ outer layer maintains good thermal stability without decomposition or phase transformation at 2400 °C, and only partial melting and obvious growth of the La₂Hf₂O₇ grains are observed in ablation center. The scoured molten La₂Hf₂O₇ phase and the thinning of La₂Hf₂O₇ outer layer caused by the further sintering result in the increased ablation rates of the graded coating. The excellent thermal insulation and stability of La₂Hf₂O₇ outer layer provides effective protection for internal SiC-ZrC and SiC layers. The integrity three-layer structure and the well protected inner layers demonstrate the effective design of this novel graded coating for thermal protection of C/C composites at 2400 °C.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"508 ","pages":"Article 132191"},"PeriodicalIF":5.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864532","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}

{"title":"Microstructure, wear, and corrosion behavior of an Al2O3-CePO4-MoS2 composite layer in-situ prepared by one-step micro arc-oxidation","authors":"Q. Li,&nbsp;J. Shang","doi":"10.1016/j.surfcoat.2025.132206","DOIUrl":"10.1016/j.surfcoat.2025.132206","url":null,"abstract":"<div><div>The Al₂O₃-CePO₄-MoS₂ composite layer was in-situ prepared on the surface of 6082-T6 alloy by micro-arc oxidation technology. The effects of Ce³⁺ concentrations on microstructure, wear and corrosion behavior of the ternary layer were studied. The results showed that when the Ce³⁺ concentrations in electrolyte was 7.5 g/L, the highest hardness was 961.79 HV₁, the friction coefficient was 0.56 and wear rate was 4.9 × 10^-7 mm³/N·mm, the self-corrosion current density was reduced by one order of magnitude, and the corrosion pit was significantly reduced. The wear and corrosion resistance of the Al₂O₃-CePO₄-MoS₂ layer is better than that of Al₂O₃-MoS₂ layer. The crystalline or amorphous CePO₄ and MoS₂ formed in-situ were presented around the Al₂O₃ and had synergistic effects for improving the compactness, hardness, wear, and corrosion resistance. This Al₂O₃-CePO₄-MoS₂ composite layer can be used for protection in contact systems in rainy environments.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"509 ","pages":"Article 132206"},"PeriodicalIF":5.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869802","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}

{"title":"PDMS@SiO2 surface modified superhydrophobic melamine sponges for enhanced drag reduction","authors":"Yukun Wei,&nbsp;Yiwei Hu,&nbsp;Zhaoxi Liang,&nbsp;Liran Ma","doi":"10.1016/j.surfcoat.2025.132200","DOIUrl":"10.1016/j.surfcoat.2025.132200","url":null,"abstract":"<div><div>Ocean vehicles, integral to ocean engineering, require reducing operational resistance, which is crucial. This study focuses on the modification of the surface of melamine sponge (PDMS@SiO₂) utilizing sol-gel methodology and dip coating technology, resulting in the successful fabrication of a resistance-reducing material characterized by superhydrophobicity and exceptional impact resistance. The study shows that the modified sponge has excellent superhydrophobic properties due to its controlled surface microstructure and chemical composition, with a contact angle of 160.1°. In simulated environments involving adhesion, sand impact, and durability in strong acid/alkali environments, the modified sponge maintained a water contact angle (WCA) of 130° for 24 h, representing a 19 % decrease from the initial value. Furthermore, cyclic compression tests revealed that the combination of PDMS and SiO₂ significantly improved the stability and fatigue resistance of the material, resulting in a reduction of stress attenuation from 43.9 % to 30.4 %. Additional rheometer and pipeline test results corroborated the substantial advantages of the modified sponge in minimizing fluid resistance and sustaining flow stability, with resistance reductions of up to 81 % and 60 %, respectively. This study demonstrates that the PDMS@SiO₂ modified melamine sponge has significant practical application value in reducing fluid resistance and prolonging laminar flow conditions underwater.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"509 ","pages":"Article 132200"},"PeriodicalIF":5.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874736","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}

{"title":"Experimental analysis and modeling of sp2- and sp3-bonded phase formation during boron nitride film deposition by a reactive plasma-assisted coating method","authors":"Yuya Asamoto ,&nbsp;Akira Okada ,&nbsp;Masao Noma ,&nbsp;Michiru Yamashita ,&nbsp;Shigehiko Hasegawa ,&nbsp;Keiichiro Urabe ,&nbsp;Koji Eriguchi","doi":"10.1016/j.surfcoat.2025.132190","DOIUrl":"10.1016/j.surfcoat.2025.132190","url":null,"abstract":"<div><div>Cubic boron nitride (c-BN) exhibits superior physical properties, making it highly suitable for various engineering applications. Despite their high potential, c-BN films adoption is hindered by the critical issue of delamination from the substrate. The structural transition region (STR) between the substrate and c-BN bulk film governs the delamination process because the STR suffers from residual strain and post-chemical reactions. Although the nucleation and growth of the <em>sp</em>³-bonded phase occur in the STR during the deposition of c-BN films, few models have been proposed for this mechanism. In this study, we formed c-BN films with various STR using a magnetically confined vacuum-arc plasma. The incident ion energies and metal impurity (W) concentrations were tuned using the process parameters to control the properties. The ion energy dependence addressed the presence of the threshold energy (<em>E</em>_th) for <em>sp</em>³-bond formation and <em>E</em>_th increased with higher W concentration (<em>C</em>_W). The thickness of the STR increased with <em>C</em>_W. Based on the experimental results, we proposed a model for the nucleation and growth dynamics of the <em>sp</em>³-bonded phase in the STR. The model predicted the suppression of the <em>sp</em>³-bonded phase growth by the introduction of W and an increase in <em>E</em>_th for <em>sp</em>³-bond formation. It also revealed the thickness dependence of the indentation hardness of c-BN films with various STR, that is <em>C</em>_W values. The present results contribute to the process and functional design of c-BN films.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"509 ","pages":"Article 132190"},"PeriodicalIF":5.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882791","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}

{"title":"Applicability of surface functionally graded materials for flashover mitigation: from vacuum to compressed SF6 gas","authors":"Chao Wang ,&nbsp;Yu-Long Yang ,&nbsp;Cheng-Lin Hou ,&nbsp;Wen-Dong Li ,&nbsp;Si-Le Chen ,&nbsp;Zhao-Quan Chen ,&nbsp;Guan-Jun Zhang","doi":"10.1016/j.surfcoat.2025.132166","DOIUrl":"10.1016/j.surfcoat.2025.132166","url":null,"abstract":"<div><div>Surface functionally graded materials (SFGMs) exhibit promising prospect in flashover mitigation of solid insulation in high-voltage apparatus. The construction methods and their applicability of SFGMs in various scenarios are systematically investigated in this work. Coating materials with different functional fillers were prepared to fabricated different types of SFGMs. Flashover testing results show that coating with graded permittivity (ε-SFGM) and coating with graded permittivity / conductivity (ε/ σ-SFGM) exhibit excellent electrical strength enhancement effect in compressed SF₆ gas at power frequency. In contrast, the improvement effect of SFGMs are limited in vacuum. Only ε/ σ-SFGM constructed by SiC fillers shows a better flashover mitigation effect in vacuum due to the dissipation capability of surface hetero-charge. σ-SFGM constructed by carbon nanotube fillers would deteriorate surface electrical strength both in SF₆ gas and in vacuum due to its excessive conductivity. Furthermore, numerical simulations were conducted to build the relationship between SFGMs construction methods and flashover threshold both in vacuum and compressed SF₆ gas, which are in agreement with the experimental results.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"508 ","pages":"Article 132166"},"PeriodicalIF":5.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859863","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}

{"title":"The microstructure evolution and performance enhancement mechanism of a novel laser cladding 20CrNiMoBSiY high-temperature alloy with high wear and corrosion resistance","authors":"Ting Wang ,&nbsp;Jialu Chen ,&nbsp;Youcai Zhang ,&nbsp;Tong Cui ,&nbsp;Jing Liang ,&nbsp;Suiyuan Chen","doi":"10.1016/j.surfcoat.2025.132178","DOIUrl":"10.1016/j.surfcoat.2025.132178","url":null,"abstract":"<div><div>Wear-resistant and corrosion-resistant Fe-based high-temperature alloys have great potential in laser additive manufacturing of metallurgical high-temperature friction parts. However, due to the operational temperature range of 400–800 °C, the friction parts of traditional Fe-based high-temperature alloys often exhibit issues such as poor laser formability and unstable high-temperature performance, primarily caused by cladding cracks and porosity defects. This study utilized thermodynamic phase diagram calculations to simulate the hardness and pitting resistance equivalent number (PREN) of Fe-based alloys, optimizing and designing a novel 20CrNiMoBSiY high-temperature alloy with high wear and corrosion resistance. The alloy powders were prepared using vacuum induction gas atomization (VIGA), and the formability, microstructure evolution and performance enhancement mechanism of laser cladded alloy samples were investigated. The results indicate that the optimized composition of the alloy is 20Cr17Ni2Mo2B1.1SiY. The alloy powder has a spherical shape, uniform composition, smooth surface and flowability of 16 s/50 g. The microstructure of the cladded alloy samples primarily comprises M, retained austenite, (Fe,Cr)₂(B,C), (Cr,Fe)₂₃(C,B)₆, and (Cr,Fe)₇(C,B)₃. These phases not only exhibit excellent formability but also possess high hardness, corrosion resistance, and superior high-temperature wear resistance. When the laser energy density is optimized to 138 J/mm³, the hardness of the cladding sample reaches 622 HV_0.2, the minimum corrosion current density is 5.72 × 10⁻⁶ A·cm⁻². At 800 °C, the wear rate is 42 % lower than that of the Q235 steel. The mechanism of synergistic enhancement performance of multiphase microstructure evolution in laser cladding alloys was finely clarified. A novel laser cladding 20Cr17Ni2Mo2B1.1SiY high-temperature Fe-based alloy with high wear resistance and corrosion resistance has been obtained. This work provides valuable reference for laser cladding remanufacturing of metallurgical high-temperature friction parts.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"508 ","pages":"Article 132178"},"PeriodicalIF":5.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859865","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}

{"title":"CMAS resistance of high-entropy (Dy0.2Ho0.2Er0.2Tm0.2Lu0.2)2Hf2O7 in-serviced as top TBC of Si-HfO2/Yb2Si2O7/Yb2SiO5 EBCs system: an experimental and atomistic modeling study","authors":"Hui Zhao ,&nbsp;Qiang Miao ,&nbsp;Wenping Liang ,&nbsp;Ruixiang Liu ,&nbsp;Xiaofeng Zhang ,&nbsp;Junqin Shi ,&nbsp;Brindha Ramasubramanian ,&nbsp;Seeram Ramakrishna","doi":"10.1016/j.surfcoat.2025.132183","DOIUrl":"10.1016/j.surfcoat.2025.132183","url":null,"abstract":"<div><div>The creation of a modified T/EBC system was driven by the absence of a proven strategy to enhance the intrinsic resistance of silicate EBCs to molten silicate deposits (CMAS). To address this, a high-entropy hafnate material with a defect-fluorite structure was designed using five rare earth (RE) elements: Dy, Ho, Er, Tm, and Lu. Quadruple-layer coatings consisting of (Dy_0.2Ho_0.2Er_0.2Tm_0.2Lu_0.2)₂Hf₂O₇/Yb₂SiO₅/Yb₂Si₂O₇/Si-15 mol% HfO₂ ((5RE)₂Hf₂O₇/YbMS/YbDS/15SH), prepared by plasma spray-physical vapor deposition (PS-PVD), were deposited to protect ceramic matrix composites (CMC). These coatings were evaluated for their interfacial thermochemical stability and resistance to CMAS attack. The study revealed no thermochemical reactions at the interface between the (5RE)₂Hf₂O₇ and YbMS layers following isothermal annealing at 1300 °C, 1400 °C, and 1500 °C. The (5RE)₂Hf₂O₇ layer acts as a reactive barrier, resisting CMAS infiltration and maintaining the integrity of the coating. At 1300 °C and 1400 °C, reactions between the melt and the coating result in the formation of RE-garnet phases on the surfaces. At 1500 °C, RE-garnet phases were observed at the interface between the (5RE)₂Hf₂O₇ and YbMS layers, along with the consistently observed apatite and fluorite reaction products. Most of the RE³⁺ ions dissolved from the (5RE)₂Hf₂O₇ TBCs were captured by apatite, maintaining the crystallization stability of the reaction products and acting as a permeability barrier. Furthermore, melt/coating interaction models were developed using the ab initio molecular dynamics method (CP2K package) to understand coating/deposit reactions at the atomic level, including diffusivity dynamics and diffusion energy barriers. During the cooling stage, vertical mud-cracks and bifurcated microcracks are induced by thermal stresses resulting from the mismatch in coefficients of thermal expansion (CTE) between the corroded layer and the underlying layer. As CMAS continues to infiltrate the coating, a Yb-bearing apatite layer forms and gradually thickens through the dissolution and reprecipitation reactions with the YbMS. This corrosion layer introduces additional compressive stress on the unreacted YbMS layer, promoting the formation of more bifurcated microcracks. With further infiltration of newly molten CMAS, these microstructural damages accelerate the overall degradation of the coating system.</div></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":"508 ","pages":"Article 132183"},"PeriodicalIF":5.3,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860370","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}