Wear Characteristics According of Heat Treatment of Si₃N₄ with Different Amounts of SiO₂ Nano-Colloid

This study sintered Si₃N₄ with different amounts of SiO₂ nano-colloid. The surface of a mirror-polished specimen was coated with SiO₂ nano-colloid, and cracks were healed when the specimen was treated at a temperature of 1273 K for 1 h in air. Wear specimen experiments were conducted after heat treatments for 10 min at 1073, 1273, and 1573 K. The heat-treated surface that was coated with the SiO₂ nano-colloid was slightly rougher than the noncoated surface. The oxidation state of the surface according to the heat treatment temperature showed no correlation with the surface roughness. Moreover, the friction coefficient, wear loss, and bending strength were not related to the surface roughness. Si₃N₄ exhibited an abrasive wear behavior when SKD11 was used as an opponent material. The friction coefficient was proportional to the wear loss, and the bending strength was inversely proportional to the friction coefficient and wear loss. The friction coefficient and wear loss increased with increasing amounts of the SiO₂ nanocolloid. In addition, the friction coefficient was slightly increased by increasing the heat treatment temperature