Influence of Yag Concentration and Pressing Time on Wear of Si.sub.3N.sub.4 Based Ceramics

Abrasive wear resistance of Si.sub.3N.sub.4 strongly depends on its microstructure, in particular, grain morphology. In this work, the effects of [beta]-content, [beta]-Si.sub.3N.sub.4 grain growth, and mechanical properties on wear resistance of silicon nitride-based ceramics were investigated. Ceramic rollers containing 5, 7, and 10 wt.% of YAG (yttrite aluminum garnet Y.sub.3Al.sub.5O.sub.12) were produced by the hot-pressing technology. The pressing times of 5, 15, and 30 min were used for various ceramic rollers. The weakest microstructure constituent was the brittle crystal boundary phase that broke and chipped off during the wear test. On the base of wear measurements, where the volume loss was inversely proportional to the hardness of ceramics, the wear resistance of ceramics was described by the model V ~ HV.sup.-1.