화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.103, No.9, 4840-4845, 2020
Environmental barrier coatings using low pressure plasma spray process
Yb2Si2O7/Si bilayer environmental barrier coatings (EBCs) on SiC ceramic substrate were produced by low pressure plasma spray (LPPS) process. Phase composition, microstructure, and thermal durability of LPPS Yb2Si2O7/Si coating were investigated. XRD analysis indicated that the coating is mainly composed of Yb2Si2O7 with similar to 15.5v% Yb2SiO5 phases. The LPPS EBCs have a dense microstructure with porosity less than 4%. Adhesion strength measurement indicated the LPPS EBCs have an average adhesion strength of 29.1 +/- 0.8 MPa. Furnace cycle test (FCT) on the coatings in air at 1316 degrees C was performed and the test ran for 900 cycles and there was no coating spallation/failure for LPPS Yb2Si2O7/Si EBCs. The FCT results demonstrated the excellent thermal cycle durability of LPPS EBCs. Oxidation kinetics investigation of LPPS EBCs in flowing 90% H2O (g)+10% air at 1316 degrees C showed that the thermally grown oxide (TGO) growth rate is close to the oxidation rate of pure Si in dry air and is significantly lower than that in water vapor environment. The LPPS process is promising in making highly durable Yb2Si2O7-based dense EBCs by impeding diffusion and ingression of water vapor/O-2.