OS0402 Effect of top coat spraying process on CMAS damage in thermal barrier coatings
Details
The use of thermal barrier coatings (TBCs) for turbine blades in gas turbine engines has allowed higher engine operating temperatures exceeding the order of 1200 ℃ at the surface of the TBC top coat. More recently, it has been recognized that at these high temperatures the TBCs can be damaged by calcium-magnesium-alumino-silicates (CMAS) resulting from the ingestion of siliceous minerals (dust, sand, ash) with the intake air and from unclean fuels such as a syngas and biomass gas. The damage can accelerate the cracking and delamination of the TBCs and dramatically decrease its lifetime. In the present study, the CMAS damage was simulated in laboratory employing a synthetic CMAS product on Air Plasma sprayed (APS) and Electron Beam Physical Vapour Deposition (EB-PVD) thermal barrier coatings. The changes in microstructure were characterized, and the effect of the top coat spraying process on CMAS damage was discussed.
