Contact Damage and Strength Degradation in Nitrided Pressureless Sintered (NPS) Silicon Nitrided Ceramics

Abstract

A study is made of the damage resistance and strength degradation of nitrided pressureless sintered (NPS) silicon nitride ceramics. The silicon nitride is prepared by cost-effective NPS process combining by nitridation and consecutive pressureless sintering. Contact testing with spherical indenters is used to characterize the damage response. Examination of the indentation sites indicates a quasi-plastic damage modes are observed. Bend tests on specimens containing quasi-plastic contact damages reveal those materials to be not susceptible to strength degradation.