Boron nitride (BN) is sometimes called white graphite. His get annealing technical boron or boron oxide in the atmosphere of ammonia. It is a white, similar to talcum powder, but the similarity with talc is purely external, much larger and deeper similarity is between the amorphous boron nitride and graphite.Equally constructed crystal lattices, both substances were successfully used as high-temperature solid lubricant. Hexagonal boron nitride has a number of indisputable advantages in comparison with graphite. For example, the distribution of graphite in the industry is constrained by its burning in air at temperatures above 400 °C and the interaction with the molten metal. These shortcomings are overcome with the help of hexagonal boron nitride having high resistance to oxidation and antiadhesion properties with respect to many liquid metals and alloys. Coating of boron nitride on graphite products are widely used in nonferrous metallurgy abroad. Note that with the coating thickness only 400 microns resistant of products at 700 °C increases by more than 8 times, and at 1200 °C - more than 12 times. | |
Technical features | Boron nitride (BN) is sometimes called white graphite. His get annealing technical boron or boron oxide in the atmosphere of ammonia. It is a white, similar to talcum powder, but the similarity with talc is purely external, much larger and deeper similarity is between the amorphous boron nitride and graphite. |