Silicon nitride (Si3N4) is a lightweight and hard material. It has a low thermal expansion coefficient, high mechanical strength, and high fracture toughness. It is also resistant to deformation at room temperature as well as at elevated temperatures.
Si3N4
differs from other ceramics in that it doesn't melt between 1800°C and 1900°C, instead it decomposes and sublimates into Si and N. However, stabilized forms can still be made.
