Yb₂SiO₅ (ytterbium monosilicate) top coatings and Si bond coat layer were deposited by air plasma spray method as a protection layer on SiC substrates for environmental barrier coatings (EBCs) application. The Yb₂SiO₅-coated specimens were subjected to isothermal heat treatment at 1400 °C on air for 0, 1, 10, and 50 h. The Yb₂SiO₅ phase of the top coat layer reacted with Si from the bonding layer and O₂ from atmosphere formed to the Yb₂Si₂O₇ phase upon heat treatment at 1400 °C. The oxygen penetrated into the cracks to form SiO₂ phase of thermally grown oxide (TGO) in the bond coat and the interface of specimens during heat treatment. Horizontal cracks were also observed, due to a mismatch of the coefficient of thermal expansion (CTE) between the top coat and bond coat. The isothermal heat treatment improves the hardness and elastic modulus of Yb₂SiO₅ coatings; however, these properties in the Si bond coat were a little bit decreased.

通过空气等离子喷涂法将Yb ₂ SiO ₅（单硅酸y）外涂层和Si键合涂层作为保护层沉积在用于环境屏障涂层（EBC）的SiC衬底上。将涂覆有Yb ₂ SiO ₅的样品在1400°C的空气中进行0、1、10和50 h的等温热处理。在1400℃下进行热处理时，面涂层的Yb ₂ SiO ₅相与来自键合层的Si和形成气氛的O ₂与形成Yb ₂ Si ₂ O ₇相的气氛中的O ₂反应。氧气渗透到裂缝中形成SiO ₂热处理过程中，粘结涂层和试样界面中的热生长氧化物（TGO）的第一相。由于面涂层和粘结涂层之间的热膨胀系数（CTE）不匹配，还观察到了水平裂纹。等温热处理提高了Yb ₂ SiO ₅涂层的硬度和弹性模量。但是，硅键合涂层的这些性能略有下降。