X-RAY RESIDUAL STRESS MEASUREMENT OF SINTERED Si3N4.

The residual stress on the Si//3N//4 surface prepared with several different treatments was measured by X-ray technique using a prototype Vanadium X-ray tube. A new method developed by Yoshioka et al. was employed for analysis. High compressive surface residual stress up to 1165 MPa and the stress gradient of 154 MPa/ mu m were observed on the heavily ground surface. In the case of the surface polished with wet cloth, the residual stress was minus 111 to minus 141 MPa and the stress gradient was 14 to 27 MPa/ mu m. The stress gradient near the surface must be taken into account in these cases. In order to evaluate the depth of the deformed layer of a surface ground with the cutting depth of 15 mu m, the residual stress was measured every time after the surface was removed by 2 mu m each by sputtering technique; it was concluded that the depth of the deformed layer of the ground surface was 8 mu m. Additional study results are discussed.