Comparison between plasma- and HVOF-sprayed ceramic coatings: Part II: tribological behaviour

This is the second part of comparative study between High Velocity Oxygen-Fuel (HVOF) flame-sprayed and Atmospheric Plasma-Sprayed (APS) ceramics. Dry particles abrasion test and dry sliding wear test at room temperature, 400°C and 700°C are performed. In dry sliding against SiC, at room temperature stable tribofilms are formed and mild wear (<10-6 mm³/(Nm)) occurs for all coatings. When temperature and normal load increase, making brittle cracking a significant wear mechanism, HVOF coatings become superior to APS ones, thanks to higher toughness. In dry particles abrasion, brittle fracture prevails; therefore, the tougher HVOF coatings outperform APS ones.