Heat treatment of nanostructured thermal barrier coating

A nanostructured thermal barrier coating has been prepared by air plasma spraying using YSZ (8 wt% Y2O3 partially stabilized zirconia) nano powder. The effect of annealing on the nanostructured zirconia coating has been investigated. The grain size of the nanostructured zirconia coating increased with increasing annealing time and temperature. Grains grew with preferential direction and into a columnar structure. The growth activation energy in the nanocrystalline grains is very low, which comes from existence of micro-pores in the coating and the grain-rotation-induced grain coalescence (GRIGC) mechanism.