UNLUBRICATED SLIDING WEAR MECHANISM OF FINE CERAMIC SI3N4 AGAINST HIGH-CHROMIUM CAST-IRON

The unlubricated sliding wear behaviour of hot-pressed ceramic Si3N4 against high-chromium cast iron with various matrices is studied. The wear micromechanisms of Si3N4 and high-chromium cast iron are discussed. The results show the following. (1) Ceramic Si3N4 is less stable chemically. Its wear is caused mainly by its decomposition in the wear process. The product of decomposition is the simple substance Si. (2) The wear of Si3N4 is related only to the matrix hardness of the cast iron. The higher the matrix hardness, the lower the wear of Si3N4. (3) When high-chromium cast iron is coupled with Si3N4 in the unlubricated sliding wear process the wear of the cast iron depends on two factors, i.e. the matrix hardness and ability of plastic deformation. The higher the two factors, the lower the wear of the cast iron.