Silicon nitride has high strength, especially hot pressed silicon nitride, which is one of the hardest substances in the world. It has properties such as high strength, low density, and high temperature resistance.

Si3N4 ceramics is a Covalent bond compound. The basic structural unit is the [SiN4] tetrahedron. The silicon atom is located in the center of the tetrahedron, and there are four nitrogen atoms around it, respectively located at the four vertices of the tetrahedron. Then in the form of sharing one atom for every three tetrahedrons, a continuous and solid network structure is formed in the three-dimensional space.

Silicon nitride ceramics are widely used in various fields such as thermal conductive materials, bearing materials, wear-resistant media, and structural ceramics due to their excellent properties such as high thermal conductivity, high hardness, and self-lubrication.