Effects of whisker distribution and sintering temperature of friction and wear of Si_3N_4-whisker-reinforced Si_3N_4-composites

摘要

Friction and wear behaviors of Si_3N_4-whisker-reinforced Si_3N_4-composites have been studied in different sliding directions with respect to the orientation of the Si_3N_4-whiskers by using a ball-on-disk reciprocating sliding apparatus. These ceramic samples were sintered by the gas press sintering (GPS) technique at 1875 and 2000 deg C for 4 h in 2.4 MPa of N_2 gas, where the whiskers were controlled to have unidirectional orientation with different alignments or orientation (0 deg C /90 deg C) with a cross-structure by tape-casting and stacking. The results show that for the unidirectionally orientated composites, wear rate in the direction parallel to the whiskers is much greater than in perpendicular direction. With decreasing alignment of the whiskers, the wear rate decreases in the parallel sliding direction and increases in the perpendicular direction. Wear rate of the bidirectionally oriented (BD) composites is between those of unidirectionally oriented composites in the two sliding directions. With increasing sintering temperature, the wear rate increases in both parallel and perpendicular directions. Wear process occurs periodically during sliding.