Microstructural and reliability in grinding of silicon nitride

A sintered Si3N4 matrix has been characterized by TEM. The film thickness distribution of Si3N4 was measured by high resolution transmission electron microscopy (HREM). Surface grinding is performed on two table speeds of 0.08 and 0.25 m s−1 with different depth of cut. The ground surfaces were observed with scanning electron microscopy (SEM). The surface texture was found to have greater dependence on depth of cut and table speed. The surface roughness is improved after smaller depth of cut. The flexural strength of ground specimens were measured by four-point flexure tests. The effect of depth of cut during grinding on the flexural strength and reliability of silicon nitride is investigated. The large depth of cut of 30 μm/pass resulted in a further decreased in strength of 540 MPa and a Weibull modulus of 7.5. When the depth of cut of 5 μm/pass were subjected to the ground specimens, the average strength was increased to 670 MPa and Weibull modulus to 9.1.