Abstract This work is the 2nd part of the previous work done in the series; where, for the first time controlled segmentation crack densities have been developed manually in the coatings, even after the coating deposition. Atmospheric plasma sprayed (APS) Yttria-stabilized zirconia (YSZ)-coatings are deposited on Ni-based superalloy IN738. Thermal cycling performance was tested before and after the development of controlled segmentation crack densities in the coatings at 1150 °C for 500 cycles. In the present work, failure mechanisms in un-segmented coating and alongside the effect of controlled segmentation on the thermal cycling behavior of plasma sprayed YSZ thick coatings are investigated. Results show a promising strain tolerance behavior for the segmented coatings, whereas regular conventional (un-segmented) coating could not sustain at higher temperature after its thermal cycling test. Coating microstructures reveal that four types of coating failure were observed in un-segmented regular coating and it happened due to the formation of thermally grown oxide (TGO). Whereas, segmentation helps to control the excess formation of TGO and therefore a very thin layer of TGO was observed in segmented coating and obvious no coating failure or spallation occurred.

中文翻译：

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受控分割对等离子喷涂 YSZ 厚涂层热循环行为的影响

摘要 这项工作是该系列之前完成的工作的第 2 部分；其中，第一次在涂层中手动开发受控分割裂纹密度，即使在涂层沉积之后也是如此。大气等离子喷涂 (APS) 氧化钇稳定氧化锆 (YSZ) 涂层沉积在镍基高温合金 IN738 上。在 1150 °C 下对涂层中的受控分段裂纹密度进行 500 次循环之前和之后测试了热循环性能。在目前的工作中，研究了未分段涂层的失效机制以及受控分段对等离子喷涂 YSZ 厚涂层热循环行为的影响。结果表明分段涂层具有良好的应变耐受性能，而常规的传统（未分段）涂层在其热循环测试后无法承受更高的温度。涂层微观结构表明，在未分段的常规涂层中观察到四种类型的涂层失效，这是由于热生长氧化物 (TGO) 的形成而发生的。而分段有助于控制 TGO 的过量形成，因此在分段涂层中观察到非常薄的 TGO 层，并且明显没有发生涂层失效或剥落。