Optimization of Plasma Spraying Process Parameters for Yttria Stabilized Zirconia Coatings

6-8wt. % yttria stabilized zirconia (YSZ) has been widely used as thermal barrier in gas turbine. Atmospheric plasma spraying is a well-established technique to deposit yttria stabilized zirconia coatings. The optimization of the thermal spraying process is very important that permits better understanding the interrelated role of the spray parameters. However, thermal spraying is an extremely complex process with a large number of interrelated variables, tailoring the coating formation and its properties remains big challenge. In this paper, four principal spraying parameters were selected and optimized, i.e. stand-off distance, power input, preheating temperature and powder feed rate, by orthogonal experiment design.  Their influences on the coating’s microstructures, properties as well as thermal shock resistance were studied.