Creep behaviour of two sintered silicon nitride ceramics

The high temperature mechanical properties of two sintered silicon nitride—based ceramic materials with different microstructural features, labelled N7202 and N3208, are presented. The mechanical behaviour was examined by creep tests in compression, at temperatures between 1450 and 1700 °C in argon atmosphere. The results, analysed in terms of the creep equation, yield n=0.6±0.1 and Q=470±20 kJ/mol for N7202, and n=0.6±0.1 and Q=530±10 kJ/mol for N3208. The microstructural observations allow identify a possible microscopic deformation mechanism compatible with the set of creep parameters obtained experimentally.