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 mm?/(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.