Pyrolytic boron nitride belongs to special ceramic materials. The deposition process of pyrolytic boron nitride is like "falling snow". The hexagonal small snow flakes of boron nitride fall on the base material one by one in parallel. After reaching a certain thickness, they are finally cooled and demoulded.High temperature resistance, and the strength increases with the increase of temperature, reaching the extreme value at 2200°C,Good thermal shock resistance, good thermal conductivity, low thermal expansion coefficient,High resistance, high dielectric strength, small dielectric constant, low magnetic loss tangent, and good microwave and infrared permeability.