Tribological characteristics of Si{sub}3N{sub}4-based self-lubricating materials

摘要

A new technique for fabrication of self-lubricating ceramic-based composites has been developed. Multi-channel ceramic matrices with a predetermined number, diameter, and distribution of channels are fabricated and then filled with a lubricant such as polytetrafluoroethylene or perfluoropolyether. Friction coefficients of lubricant-filled silicon nitride against 52100 steel were found to be 0.1 to 0.2, in contrast with pure silicon nitride for which values of 0.6 to 0.7 were found. This friction reduction is insensitive to applied load or to sliding speed. The controlled pattern of porosity allows these materials to have lubricant loading of 7.5 to 10 volume percent, instead of 20-25% typical of traditional self-lubricating materials. This configuration permits higher crushing resistance and stiffness in comparison with conventional self-lubricating antifriction materials.