Boron Nitride is with high-temperature resistance, high thermal conductivity, and high electrical insulation. And it’s easy to machine to high precision parts with low density, non-toxic and self-lubricating properties. So it’s an ideal choice to use as a high temperature conducting material.
Boron Nitride parts in polysilicon ingot furnace can work longer than Alumina. Alumina will crack easily when the temperature goes up quickly and Boron Nitride won’t crack in the same situation.