Silicon Nitride Wear Mechanisms: Rolling and Sliding Contact

Abstract

Experimental investigation of lubricated rolling and sliding contact for three types of Si₃N₄ against nodular cast iron reveal that additives to the Si₃N₄ and processing methods affect wear rates and wear modes. The friction coefficient is governed by the contact type rather than by the material type. In rolling contact tests, grain pullout of Si₃N₄ caused a higher wear rate than submicron chipping. In sliding tests, tungsten carbide particles added in the Si₃N₄ matrix inhibit the wear by 50 percent. Schematic drawings of these wear processes are presented representing the wear modes in a stepwise manner.