High temperature deformation of a GPS silicon nitride

Compressive creep and stress relaxation tests have been performed in the 14 00-1650 degreesC temperature range on a Gas Pressure Sintered (GPS) silicon nitride. It is a material with a high thermomechanical resistance due to t he absence of intergranular glassy films which commonly reduce the intrinsi c properties of pure Si3N4. Besides, the tensile mechanical behaviour betwe en 1600 and 1680 degreesC shows a non-common stress peak.