Boron nitride is a crystal composed of nitrogen atoms and boron atoms. Chemical composition is 43.6 boron and 56.4 nitrogen, available in four different variants: hexagonal boron nitride (HBN), rhombohedral boron nitride (RBN), cubic boron nitride (CBN) and wurtzite boron nitride (WBN).

CBN is usually black, brown or dark red crystals with a sphalerite structure and good thermal conductivity. Second only to diamond in hardness, it is a super-hard material commonly used as tool material and abrasive.

Boron nitride

Boron nitride is chemically resistant and is not corroded by inorganic acids and water. The boron-nitrogen bond is broken in hot concentrated alkali. It begins to oxidize in air above 1200℃. The melting point is 3000℃, and it starts to sublimate slightly below 3000℃. It begins to decompose at about 2700°C in vacuum. Slightly soluble in hot acid, insoluble in cold water, relative density 2.25. The compressive strength is 170MPa. The maximum operating temperature is 900°C in an oxidizing atmosphere, and can reach 2800°C in an inactive reducing atmosphere, but its lubrication performance is poor at normal temperature. Most properties of boron carbide 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 Transparent to infrared rays.

Application fields

1. Release agent for metal forming and lubricant for metal drawing.

2. Special electrolytic and resistive materials in high temperature conditions.

3. High-temperature solid lubricants, extrusion anti-wear additives, additives for the production of ceramic composites, refractory materials and antioxidant additives, especially for resistance to molten metal corrosion, thermal enhancement additives, high-temperature resistant insulation Material.

4. Heat sealing desiccant for transistors and additives for polymers such as plastic resins.

5. Boron nitride products pressed into various shapes can be used as high temperature, high voltage, insulation and heat dissipation components.

6. Heat shielding materials in aerospace.

7. With the participation of catalysts, it can be converted into cubic boron nitride as hard as diamond after high temperature and high pressure treatment.

8. Structural materials of atomic reactors.

9. The nozzle of aircraft and rocket engines.

10. Insulator for high voltage, high frequency electricity and plasma arc.

11. Packaging materials to prevent neutron radiation.

12. Superhard materials made from boron nitride can be made into high-speed cutting tools and drill bits for geological exploration and oil drilling.

13. In metallurgy, it is used as a separation ring for continuous steel casting, a spout for amorphous iron, and a release agent for continuous aluminum casting (various optical glass release agents)

14. Make evaporation boats for various capacitor film aluminum plating, picture tube aluminum plating, display aluminum plating, etc.

15. Various fresh-keeping aluminum-plated packaging bags, etc.

16. Various laser anti-counterfeiting aluminum plating, trademark hot stamping materials, various cigarette labels, beer labels, packaging boxes, cigarette packaging boxes, etc.

17. Cosmetics are used as fillers in lipsticks, which are non-toxic, lubricating and shiny.