Abstract Gas turbine engines are exposed to severe oxidation and thermal shock under service conditions. Thermal barrier coatings (TBCs) are used to protect metallic components of gas turbines against such failures. Yttria stabilized zirconia (YSZ) has been the most common top coating material for TBC systems. However, rare earth zirconates such as La2Zr2O7 and Gd2Zr2O7 stand out as alternatives to YSZ top coating for TBCs. In this study, Inconel 718 substrates were coated with CoNiCrAlY using cold gas dynamic spray (CGDS) technique, which is a promising technology for bond coat spraying. All the ceramic top coats were produced by electron beam physical vapor deposition (EB-PVD) method that provides high strain tolerance under thermal loadings. To predict the lifetime of TBCs, the samples were subjected to furnace cycling tests at 1150 °C. After the tests, the microstructure of thermally grown oxide (TGO) layers, crack formations and chemical compatibility between the coating layers were investigated in detail. Results show that TBCs with double layered rare earth zirconate exhibit longer lifetime as compared to single layered TBCs.

中文翻译：

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氧化钇稳定氧化锆 (YSZ)、La2Zr2O7、Gd2Zr2O7、YSZ/La2Zr2O7 和 YSZ/Gd2Zr2O7 热障涂层 (TBC) 在热循环暴露中的界面失效行为

摘要 燃气涡轮发动机在使用条件下会受到严重的氧化和热冲击。热障涂层 (TBC) 用于保护燃气轮机的金属部件免受此类故障的影响。氧化钇稳定氧化锆 (YSZ) 一直是 TBC 系统最常见的顶层涂层材料。然而，稀土锆酸盐，如 La2Zr2O7 和 Gd2Zr2O7，作为 TBC 的 YSZ 顶部涂层的替代品脱颖而出。在这项研究中，Inconel 718 基材使用冷气动态喷涂 (CGDS) 技术涂覆 CoNiCrAlY，这是一种很有前途的粘合涂层喷涂技术。所有陶瓷面漆均采用电子束物理气相沉积 (EB-PVD) 方法生产，可在热负荷下提供高应变耐受性。为了预测 TBC 的寿命，样品在 1150 °C 下进行了炉循环测试。测试后，详细研究了热生长氧化物 (TGO) 层的微观结构、裂纹形成和涂层之间的化学相容性。结果表明，与单层 TBC 相比，具有双层稀土锆酸盐的 TBC 具有更长的寿命。