Effect of Grinding on Fatigue Behavior of Ceramics at Ambient Temperature

The decrease in the fatigue parameter n of ground ceramics and its effect on lifetime were discussed. The decrease was observed in dynamic fatigue tests of nonoxide ceramics containing a glassy phase and of oxide ceramics. It is considered that the decrease in value is mainly dependent on the degree of stress corrosion due to water vapor. We also revealed that the decrease in the n value can be prevented by controlling the grain depth of cut g below a critical value (gcr)f. The static fatigue test of ground ceramics was also carried out and the shortening of lifetime was observed, although the strength degradation was small.