Thermal conductivity and phase stability of plasma sprayed ZrO2-Y2O3-La2O3 coatings

Thermal conductivity and phase stability of La2O3,Y2O3 stabilized ZrO2 plasma sprayed coatings were investigated. La2O3 was selected as a stabilizer because it had a significant effect on reducing densification of Y2O3 stabilized ZrO2 (YSZ). The developed coating showed low thermal conductivity even after high temperature exposure due to its high resistance to sintering. However, phase stability and thermal cycle life of the coating decreased as the amount of La2O3 was increased. It was concluded that optimum amount of La2O3 addition was about 1 mol% to suppress sintering with little degradation of other properties.