Tribological properties of silicon carbide in the metal removal process

Abstract

In this paper material properties are reviewed as they relate to the adhesion, friction and wear of single-crystal silicon carbide in contact with metals and alloys that are likely to be involved in a metal removal process such as grinding. For simplicity of discussion, the tribological properties of concern in the metal removal processes are separated into two contributions: the first is that in which metal removal arises primarily from adhesion between sliding surfaces in contact and the second is where metal removal occurs as a result of the silicon carbide sliding against a metal, indenting into it and plowing a series of grooves or furrows. The paper also deals with the fracture and deformation characteristics of the silicon carbide surface. The adhesion, friction and metal transfer to silicon carbide are related to the relative chemical activity of the metals: the more active the metal, the higher the adhesion and friction and the greater the metal transfer to the silicon carbide. The atomic size and the content of alloying elements play a dominant role in controlling the adhesion and friction properties of alloys. The friction and abrasive wear (metal removal) decrease linearly as the shear strength of the bulk metal increases. The atomic size and the content of alloying elements are also important parameters in controlling the friction and abrasive wear of alloys. They decrease both as the solute-to-solvent atomic radius ratio increases or decreases linearly from unity and with an increase in solute content. The surface fracture of silicon carbide is due to cleavages of {0001}, {101̄0} and/or {112̄0} planes.