Abstract
Friction behavior of silicon nitrides was evaluated in oil lubricant condition, and the effects of surface treatment including plasma treatment were investigated. The normal coefficient of friction was approximately 0.10 while the considerably lower coefficients were occasionally obtained in plasma treated silicon nitrides. The frictional surface was investigated with AFM and nano-indentation technique, and it was revealed that a very thin layer was formed on the frictional surface and has low yield stress. The formation of the surface layer during plasma treatment and friction tests was considered to be responsible for the low friction.
