Abstract: A Si₃N₄-based composite ceramic tool material was fabricated by microwave sintering. Its tribological behaviors and wear mechanisms sliding against three counterpart materials (i.e. Si₃N₄, cement carbide and bearing steel GCr15) under the several applied loads were studied. The results show that in sliding against Si₃N₄, the wear rate was highest and increased rapidly with the increase of applied load. The wear was mainly in the form of brittle flaking. In sliding against cement carbide, the friction coefficient was lowest. Transition of wear mechanism from abrasive wear to abrasive and fatigue wear was observed by increasing the applied load. In sliding against bearing steel GCr15, the wear rate was smallest and decreased with the increase of applied load. This was due to the transferred metal formed on the surface of wear tracks. Compared with the commercial Si₃N₄ ceramic of SNGN120408, the coefficient of friction was slightly lower and the wear rate was reduced by about 14.17%~59.49%.