High-Temperature Wear and Abradable Behaviors of Yb 2 Si 2 O 7 -CaF 2 Composite Coatings Fabricated by Atmospheric Plasma Spray

Ceramic matrix composites (CMCs) have become important structural materials of aero-engines under elevated operating temperature while the abradable ceramic coatings matched with CMCs are seldom reported. In this work, the atmospheric plasma spray (APS) technique was used to fabricate and design Yb 2 Si 2 O 7 -based coatings with various contents of CaF 2 . The phase composition and microstructure of the coatings, as well as Rockwell hardness, were characterized. The wear and abradable behaviors of the coatings including friction coefficients and volume wear rates were evaluated at room temperature and 900 °C, respectively. The results show that the Rockwell hardness and friction coefficients decreased, and the volume wear rates of the coatings at room temperature significantly raised with the increase of CaF 2 content. The coatings exhibited quite different behaviors at 900 °C compared with those at room temperature owing to the lubricant effect of CaF 2 . The morphologies of the coatings after the wear tests were characterized and the possible failure mechanisms were analyzed, and this study may provide guidelines for the application of the abradable coatings suitable for CMCs.