Effects of processing on tribological properties of carbide derived carbon on silicon carbide

The physical, mechanical, and tribological properties of carbide derived carbon (CDC) were investigated. CDC is a new form of carbon, which can be produced from carbide ceramics by the reaction with chlorine gas at elevated temperatures much lower than those used for sintering or graphitization. The thickness of CDC formed from SiC in a 3.5% Cl2-Ar mixture at 1000°C and 900°C fits a parabolic rate equation. The rate of CDC growth is controlled primarily by diffusion through the CDC layer.; Ball-on-disk measurements have shown that CDC has lower friction coefficient (0.1-0.2) than sintered carbides and better wear resistance than graphite. The wear rate of CDC sliding against a harder material such as a Si3 N4 ball is approximately 10-5 mm3/N-m, which is an order of magnitude less than SiC sliding against a Si3N 4 ball under similar conditions. The wear rate of CDC in room temperature BOD tests decays with sliding distance and can be fit to a logarithmic equation.; The hydrogen treatment of CDC at 800°C for 8 hours in the 5% H 2-Ar mixture after the CDC has cooled down to room temperature improves the tribological properties by decreasing the friction coefficient to half of its original value and the wear rate to roughly a third of its original value.