White loose powder, insoluble in cold water, slightly soluble in hot acid.
It is used to make refractory materials, furnace insulation materials, and also used in electronics, machinery, aviation and other industries.
Widely used in insulators for high-voltage high-frequency electricity and plasma arcs, coatings for automatic welding high-temperature resistant frames, materials for high-frequency induction furnaces, solid-phase admixtures for semiconductors, structural materials for atomic reactors, and packaging materials to prevent neutron radiation , the transmission window of the radar, the medium of the radar antenna and the composition of the rocket engine, etc.
