Slow crack growth behavior of two gas pressure sintered Si3N4 ceramics with different additives; a Yb2Si2O7 composition and an A12O3-Y2O3 composition, was investigated by constant stress-rate ("dynamic fatigue") testing at 1400°C. The slow crack growth parameter, n, was 14.7 and 6.3 for Si3N4 with Yb2Si2O7 and AI2O3-Y2O3 compositions, respectively. Superior crack growth resistance of Si3N4 with Yb2Si2O7 composition was due to its higher refractoriness of intergranular glassy films, compared to Si3N4 with A12O3-Y2O3 composition.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry