Physical and chemical properties of boron nitride

Physical properties

CBN is usually black, brown or dark red crystals with a zinc blende structure with good thermal conductivity. Hardness is second only to diamond, it is a super hard material, often used as tool materials and abrasives. [3]

Boron nitride has chemical resistance properties and is not corroded by inorganic acids and water. The boron-nitrogen bond is broken in the hot concentrated alkali. Above 1200℃, it will start to oxidize in the air. It begins to decompose at about 2700°C under vacuum. Slightly soluble in hot acid, insoluble in cold water, relative density 2.29. The compressive strength is 170MPa. The maximum operating temperature is 900°C in an oxidizing atmosphere, while it can reach 2800°C in an inactive reducing atmosphere, but the lubrication performance is poor at room temperature. Most of the properties of boron nitride are better than carbon materials. For hexagonal boron nitride: low friction coefficient, good high temperature stability, good thermal shock resistance, high strength, high thermal conductivity, low expansion coefficient, high resistivity, corrosion resistance, microwave or transparent Infrared.

Material structure

Hexagonal boron nitride crystals, the most common graphite lattice, there are also amorphous variants, in addition to the hexagonal crystal form, there are other crystal forms of boron nitride, including: rhombohedral boron nitride (r-BN), cubic Boron nitride (c-BN), wurtzite type boron nitride (w-BN). People even found two-dimensional boron nitride crystals like graphene