Abstract
Plasma spraying of thermal barrier coatings (TBCs) on gas turbine parts is widely used today either to enable higher turbine inlet temperatures with consequent improvement of combustion efficiency or to reduce the requirements for the cooling system and increase components life-time. Development of low conductivity TBCs, which allows us to further increase gas turbine efficiency and availability, is an ongoing challenge. In order to get low thermal conductivity values an experimental program was conducted. Two zirconia powders were used for coating deposition: yttria partial stabilised zirconia (YPSZ) and dysprosia partial stabilised zirconia (DyPSZ). Microstructure evaluations were performed to evaluate the influence of the spraying parameters on the coating morphology and porosity level. Two methods were utilised to evaluate the coatings thermal conductivity: Laser Flash (LF) and Transient Plane Source (TPS). A comparison between the two methods was made as well as a correlation study between coating microstructure/composition and thermal conductivity (TC).
