Comparative study of EB-PVD gadolinium-zirconate and yttria-rich zirconia coatings performance against Fe-containing calcium-magnesium-aluminosilicate (CMAS) infiltration
Comparative study of EB-PVD gadolinium-zirconate and yttria-rich zirconia coatings performance against Fe-containing calcium-magnesium-aluminosilicate (CMAS) infiltration
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DOI：
10.1016/j.corsci.2021.109660
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发表时间：
2021-07-22
影响因子：
8.3
通讯作者：
Schulz, Uwe
中科院分区：
文献类型：
--
作者：
Chavez, Juan J. Gomez;Naraparaju, Ravisankar;Schulz, Uwe
这项详细的研究比较和对比了电子束物理气相沉积 (EB-PVD) 生产的锆酸钆 (GZO) 和富氧化钇氧化锆（65YZ，65 wt% Y2O3 其余氧化锆）涂层的抗钙镁铝硅酸盐 (CMAS) 渗透行为。通过在 1250 摄氏度下进行长期渗透测试（长达 50 小时），研究了渗透动力学以及不同反应产物的稳定性和保护性质。结果表明，对于本研究中使用的特定微结构，65YZ 与 GZO 相比具有更高的渗透阻力，并形成更薄的反应层。分析表明，65YZ 的更好性能与协同反应机制有关，其中包括富钙磷灰石和均匀层石榴石相的形成。与 65YZ 相比，GZO 的磷灰石形成需要更多的稀土 (RE)，这意味着在形成磷灰石晶体之前会溶解更多的 Gd，这导致与 65YZ 相比 GZO 层的消耗更高。详细讨论了这些机制的含义，涉及石榴石形成的趋势、磷灰石相与 Ca 和 RE 含量的平衡，以及由于稀土溶解到玻璃中而导致粘度降低的影响。然而，本研究中使用的涂层的微观结构差异也可能影响不同的渗透阻力和反应动力学，需要考虑。
This detailed study compare and contrasts the calcium-magnesium-aluminosilicate (CMAS) infiltration resistance behavior of electron-beam physical vapor deposition (EB-PVD) produced gadolinium zirconate (GZO) and yttria rich zirconia (65YZ, 65 wt % Y2O3 rest zirconia) coatings. The infiltration kinetics, as well as the stability and protective nature of different reaction products, were studied by performing long term infiltration tests (up to 50 h) at 1250 degrees C. The results reveal that for the specific microstructures used in this study, 65YZ has a higher infiltration resistance and forms a thinner reaction layer compared to GZO. The analysis indicates that the better performance of 65YZ is associated with a synergetic reaction mechanism, which includes the formation of Ca-rich apatite and a uniform layer of a garnet phase. The formation of apatite requires more rare-earth (RE) in the case of GZO than its 65YZ counterpart, meaning that more Gd would be dissolved before forming apatite crystals, which leads to higher consumption of the GZO layer compared to that of 65YZ. The implications of these mechanisms are discussed in detail concerning the tendency of garnet formation, equilibration of the apatite phase with Ca and RE content, and the effects of the reduction in viscosity due to the RE dissolution into the glass. However, microstructural differences in the coatings used in this study might also affect the diverging infiltration resistance and reaction kinetics and need to be considered.