Effect of Temperature on the Dry Sliding Friction and Wear of Rice Bran Ceramics against Different Counterpart Materials

In this study, we investigated the effect of temperature on the friction and wear of rice bran (RB) ceramics, a hard porous carbon material made from rice bran, sliding against alumina, stainless steel, and bearing steel balls under dry conditions. Friction tests were performed using a ball-on-disk-type friction tester wherein a ceramic heater was installed in the rotational stage. The surface temperature of the RB ceramic disk specimens was controlled at 20, 100, 150, or 200°C. The normal load was 1.96 N, sliding velocity was 0.1 m/s, and number of cycles was 20,000. The effect of surface temperature on the friction and wear of RB ceramics substantially differed among the ball material types. The friction coefficient for the RB ceramics sliding against an alumina ball decreased with increasing temperature and exhibited an extremely low value (0.045) at 200°C. The friction coefficient in the case of the RB ceramics sliding against a stainless steel ball exhibited a stable value as the temperature was increased to 150°C and slightly decreased as the temperature was increased further, reaching a low value of 0.122 at 200°C. The friction coefficient for the RB ceramics sliding against bearing steel ball drastically increased with increasing temperature, reaching 0.381 at 200°C. The specific wear rate of the RB ceramics increased with increasing temperature; it was lowest when sliding against alumina and highest when sliding against bearing steel. The wear of the alumina ball was the lowest and that of the bearing steel ball was the highest under all investigated temperature conditions. On the basis of these results, we concluded that alumina is a promising counterpart material for RB ceramics sliding at high temperatures (≤200°C).