Fabrication and tribological characterization of gradient carbon layer derived from SiC-TiC composites

Abstract

Carbide based ceramics are frequently used for the tribological applications, such as mechanical seals, owing to their good mechanical and chemical properties. Recently, studies of the tribological properties of these applications have become increasingly important due to the increasing need for severe operating conditions. In this study, the surface modification of carbide ceramics was attempted to improve the triblogical properties. Carbon layers were prepared on SiC-TiC ceramics using a moderate and high temperature chlorination process. The microstructure and worn surfaces were analyzed by scanning electron microscopy and an alpha-step profilometer, respectively. Tribological tests were carried out on chlorinated SiC-TiC surfaces using a ball on disc wear tester. Since carbon atoms in TiC were derived at lower temperatures than SiC, the distribution of carbon atoms within the modified layers were synthesized by the difference in reaction temperature and reaction time. The tribological properties were varied by the volume fraction of carbon and SiC in the modified layer. The friction coefficient and wear rate were decreased by controlling the structure and composition of the carbon based layer from 0.22 to 0.18 and 7.91 to 1.92 (x10(-6)mm(3)/N.m), respectively. (C) 2010 The Ceramic Society of Japan. All rights reserved.