Silicon Nitride — Thermal Expansion

Because of its excellent thermal and mechanical properties, silicon nitride is used more and more for high-tech applications (e.g. valves in automobile engines). Of course, the properties of the final parts are heavily influenced by the production/sintering process. Depicted in this figure is the thermal expansion of a silicon nitride green body. The sintering step starting at 1201°C is due to the influence of the sintering additives. The main shrinkage step occured at 1424°C (extrapolated onset). The effect above 1760°C is most probably due to evaporation of additives. (measurement with DIL 402 C)