WATER-LUBRICATED PIN-ON-DISK TESTS WITH CERAMICS

Several material combinations lubricated with water, were investigated by performing pin-on-disc friction and wear tests. The materials were alumina, zirconia-toughened alumina (ZTA), magnesia-partially-stabilized zirconia (PSZ), silicon carbide (SiC), sialon and stainless steel. The best performance under conditions of boundary lubrication was found for the all-alumina sliding pair. Very high coefficients of friction and wear and an abundant formation of wear debris occurred when PSZ was slid on itself. Tribochemical reactions caused strong "running-in" wear of the silicon-based ceramics. The reaction products were dissolved in the water, and the sliding surfaces formed were smooth enough to make fluid film lubrication possible. Unlike pairing of the ceramics did not bring remarkable tribological benefits, but it provided the opportunity to optimize the tribological performance and mechanical properties of the system. In the ceramic-steel sliding pairs, strong surface interactions occurred.