Effects of Substrate Temperature and Bond Coat Thickness on the Life of TBCs in EB-PVD Process

Zirconia based TBCs (thermal barrier coatings) with different substrate temperature and thickness of bond coating were prepared by EB-PVD process. The relationship between the cyclic life of TBCs with the substrate temperature and bond coat thickness was investigated. The results show that there is a critical substrate temperature range of 650 similar to 700 degrees C and for the YSZ top the proper temperature is near 800 similar to 900 degrees C. TBCs life time will be elongated with the increasing of bond coat thickness in a certain range. But the life of TBCs is short and distributed irregularly when the bond coating is too thin. So in practice, the bond coating should be made as thick as possible under condition limitation.