Abstract The isothermal oxidation of 8 wt% Y2O3 stabilized ZrO2 (YSZ) thermal barrier coating (TBC) and growth behavior of thermal growth oxide (TGO) have been investigated. The average thicknesses of oxide scale and internal oxidation zone of the substrate with coating are significantly smaller compared with the bare substrate. The TGO layer evolves from a black single-layer to a double-layer structure. The lower black layer is composed of α-Al2O3, and the upper gray layer consists of mixed oxides of (Ni,Co)O, (Co,Ni)Cr2O4 and (Ni,Co)Al2O4 at 1000 °C by TEM analysis. The formation of the solid solution oxides is probably related to the intense diffusion at high temperature. The growth stresses of α-Al2O3, NiCr2O4, NiO and CoO are calculated to be 30.88, 62.99, 34.52 and 35.85 GPa, respectively, indicating that mixed oxides, especially the spinel phase, are very detrimental to the stability of the TBC. The growth kinetics of TGO layer and the oxidation mechanism of YSZ TBC are illustrated.

中文翻译：

---

Ni基高温合金上NiCoCrAlY-YSZ热障涂层的等温氧化和TGO生长行为

摘要 研究了 8 wt% Y2O3 稳定化 ZrO2 (YSZ) 热障涂层 (TBC) 的等温氧化和热生长氧化物 (TGO) 的生长行为。与裸基体相比，带涂层基体的氧化皮和内部氧化区的平均厚度明显更小。TGO层由黑色单层演变为双层结构。下部黑色层由 α-Al2O3 组成，上部灰色层由 (Ni,Co)O、(Co,Ni)Cr2O4 和 (Ni,Co)Al2O4 的混合氧化物组成，在 1000°C 下通过 TEM 分析。固溶体氧化物的形成可能与高温下的强烈扩散有关。计算得出 α-Al2O3、NiCr2O4、NiO 和 CoO 的生长应力分别为 30.88、62.99、34.52 和 35.85 GPa，表明混合氧化物、特别是尖晶石相，对TBC的稳定性非常不利。说明了 TGO 层的生长动力学和 YSZ TBC 的氧化机制。