Effect of doping elements on the friction and wear properties of SiC in unlubricated sliding condition

The effect of doping elements on the friction and wear properties of silicon carbide is investigated in unlubricated sliding under varying humidity conditions. Doping elements (Al, Mg and P) appreciably affect the friction coefficient at lower humidity (30% RH) than at higher humidity (60% RH). The change in the kinetics of tribochemical reactions at lower humidity is attributed to chemisorption and microstructural changes. At higher humidity, coefficient of friction (COF) decreases but the effect of doping elements is rather insignificant. This is attributed to faster kinetics of tribochemical reactions. Continuing adhesion, twisting and rolling of small wear particles during the wear process results in the formation of long needle-like debris.