| Abstract: |
This study combined experimental results with stress simulation aiming to provide an insight into the failure mechanism of CMAS corroded YSZ coating and double layered LC/YSZ coating during thermal cycling test. Due to the good CMAS corrosion resistance, the double layered LC/YSZ coating had higher thermal cycling lifetime compared to single YSZ coating. CMAS penetrated into the whole YSZ coating, which remarkably increased the out-of-plane stress and in-plane stress of coating and resulted in the formation of coarse cracks. The failure of double layered LC/YSZ coating was mainly due to sintering of LC layer. The large in-plane stress at the surface of LC layer induced the formation of verticle cracks, which branched and deflected along the LC/YSZ interface, leading to the spallation of LC layer. The sudden decrease of thermal expansion coefficient and CMAS corrosion showed little influence on thermal cycling lifetime of LC/YSZ coating.
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