The hot corrosion resistance of air plasma-sprayed 8YSZ-Al2O3-multiwall carbon nanotubes (MWCNTs) has been analyzed and compared to that of 8YSZ coating. The feedstock constituents were blended to produce 8YSZ-20% alumina-0%MWCNT (type II), 8YSZ-19% alumina-1%MWCNT (type III), and 8YSZ-17% alumina-3%MWCNT (type IV) feedstock. After the cyclic hot corrosion (cHC) test in Na2SO4-60%V2O5 molten salt, the morphology of coatings was analyzed using EDS, SEM, and XRD while the coating cross-section properties were determined by a nanoindentation test and the infiltration resistance of the topcoats was estimated from the Weibull modulus (m) of the bond coat (BC) properties. The formation of YVO4 and phase transformation of zirconia from tetragonal to monoclinic were found as important degrading mechanisms of the coatings. The difference in coefficient of thermal expansion also proved to be detrimental to the performance of the coating. The zirconia monoclinic phase content for the 8YSZ(type I), type II, type III, and type IV coatings was around 86, 80, 92, and 89%, respectively, after the cyclic hot corrosion test. The Weibull analysis of the Young’s modulus of the bond coat showed that the type IV coating exhibited the highest heterogeneity in Young’s modulus. Finally, the addition of MWCNT was found to be detrimental in the cyclic hot corrosion test as it led to the cracking of the coatings.

中文翻译：

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等离子喷涂复合涂层在Na2SO4-60%V2O5熔盐环境中的循环热腐蚀性能评价

空气等离子喷涂 8YSZ-Al2O3-多壁碳纳米管 (MWCNTs) 的耐热腐蚀性能已被分析并与 8YSZ 涂层的耐热腐蚀性能进行了比较。将原料成分混合以生产 8YSZ-20% 氧化铝-0%MWCNT（II 型）、8YSZ-19% 氧化铝-1%MWCNT（III 型）和 8YSZ-17% 氧化铝-3%MWCNT（IV 型）原料. 在 Na2SO4-60%V2O5 熔盐中进行循环热腐蚀 (cHC) 测试后，使用 EDS、SEM 和 XRD 分析涂层的形貌，同时通过纳米压痕测试确定涂层横截面性能和耐渗透性。面漆是根据粘合层 (BC) 特性的威布尔模量 (m) 估算的。YVO4 的形成和氧化锆从四方晶到单斜晶的相变被发现是涂层的重要降解机制。热膨胀系数的差异也证明对涂层的性能有害。在循环热腐蚀试验后，8YSZ（I 型）、II 型、III 型和 IV 型涂层的氧化锆单斜相含量分别约为 86%、80%、92% 和 89%。粘合涂层杨氏模量的威布尔分析表明，IV 型涂层表现出最高的杨氏模量不均匀性。最后，发现添加 MWCNT 在循环热腐蚀试验中是有害的，因为它会导致涂层开裂。粘合涂层杨氏模量的威布尔分析表明，IV 型涂层表现出最高的杨氏模量不均匀性。最后，发现添加 MWCNT 在循环热腐蚀试验中是有害的，因为它会导致涂层开裂。粘合涂层杨氏模量的威布尔分析表明，IV 型涂层表现出最高的杨氏模量不均匀性。最后，发现添加 MWCNT 在循环热腐蚀试验中是有害的，因为它会导致涂层开裂。