INFLUENCE OF GRINDING PARAMETERS ON STRENGTH-DOMINATING NEAR-SURFACE CHARACTERISTICS OF SILICON-NITRIDE CERAMICS

The complex relationship between machining parameters, surface quality and strength of sintered silicon nitride (SSN) was investigated using roughness measurements, SEM observations, strength rests and X-ray di ffraction techniques. Conventional grinding as well as creep-feed grin ding, high-speed grinding and grinning at high material removal rates have been studied. From the results detailed information is derived ab out the effect of different grinning parameters on near-surface effect s and on strength. The results demonstrate the limitations of often pr oposed correlations between strength and other 'characteristics' of ma chined surfaces, like roughness values or theoretically derived values of the chip thickness. Guidelines for optimized grinning parameters a re established. (C) 1996 Elsevier Science Limited.