DRY AND WATER-LUBRICATED SLIP-ROLLING OF SI3N4-BASED AND SIC-BASED CERAMICS

Tests on self-mated Si3N4- and SiC-based ceramics as well as ceramic-c eramic composites were performed in an Amsler-type wear tester under d ry and water-lubricated rolling conditions with 10% slip. Under dry fr iction, wear coefficients of the materials varied by four decades. Unl ubricated wear coefficients below 10(-7) mm3/(N.m), defined as a pract ical limit for applicability, can be achieved with Si3N4-TiN below 775 MPa and with HIP-SiC below 750 MPa. HIPped Si3N4 and hot-pressed SiC- TiC under dry friction exhibit a small dependency of wear coefficient on Hertzian pressure, with wear coefficients below 10(-6) mm3/(N.m). T he lowest wear coefficient below 10(-6) mm3/(N.m) with water lubricati on was found for Si3N4-TiN and S-RBSi3N4; water reduces the variabilit y in wear coefficient for Si3N4- and SiC-based ceramics.