Wear of the ultrahard B4C–SiC–TiB2 ceramic composite in unlubricated sliding contact with ceramic counter-parts

Abstract

The wear performance of the ultrahard B4C–SiC–TiB2 ceramic composite was investigated in unlubricated sliding contact in various friction pairs with other ceramics of very different mechanical properties (diamond, Y2O3-stabilised ZrO2, Al2O3, Si3N4, and borosilicate glass) under otherwise identical contact conditions. It was found that this composite is, due to its ultra-high hardness (∼35(1) GPa), a promising material for tribological applications (sliding-wear resistance of the order of 105–108 (N·m)/mm3) that undergoes only very mild two-body abrasion against diamond (∼6.5(7)·10−9 mm3/(N·m)) and mild three-body abrasion against ZrO2, Al2O3, Si3N4, and borosilicate glass (10−6–10−7 mm3/(N·m)). It was also found that the B4C–SiC–TiB2 composite wore faster against Si3N4 (∼3.1(3)·10−6 mm3/(N·m)) than against Al2O3 (∼1.8(3)·10−6 mm3/(N·m)), next against borosilicate glass (∼1.1(1)·10−6 mm3/(N·m)), and finally slowest against ZrO2 (∼7.2(6)·10−7 mm3/(N·m)), a trend that was justified based on the consideration that its three-body abrasion is a complex phenomenon conditioned by the abundance and hardness of the wear debris, the formation and coherence of protective tribolayers (either oxide or material transfer), and the effective contact pressure acting on the wear debris. Finally, implications arising from the study are presented.