High Temperature Stability and Thermal Cycling Life of Plasma Sprayed Nanostructured Thermal Barrier Coating with Low Impurity Content

Nanostructured 8YSZ(6 similar to 8 wt.% Y2O3 partially stabilized zirconia) thermal barrier coatings(TBCs) have been proved which can improve the thermal conductivity and durability compare to conventional coatings. There are still concerns in the engineer and scientific community about the stability of nanostructured 8YSZ coatings at high temperatures. In this work, modified nano-8YSZ coating with low impurity content and optimized microstructure was prepared by atmospheric plasma spraying. The effects of annealing on the nano-8YSZ coating were investigated, and thermal cycling life under high temperature gradient was analyzed. The result revealed that the modified nano-8YSZ coating exhibited low content of monoclinic phase after annealed 100h at 1400 degrees C, and extra low linear contraction through the thickness of the coatings, about 68% lower than that for the common nano-8YSZ coating. The modified nano-TBC exhibited a thermal cycling lifetime of 1429 cycles, whereas failure of the common nano-8YSZ coating TBC occurred within 800 cycles. Improved high temperature stability could be the main reason for longer thermal cycling life of the modified nano-TBC.