Nano nanometer level boron nitride sheet powder and its application

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What is boron nitride?

     boron nitrideIt is a crystal composed of nitrogen atoms and boron atoms. The chemical composition is 43.6% boron and 56.4% nitrogen, with four different variants: hexagonal boron nitride (HBN), rhombohedral boron nitride (RBN), cubic boron nitride (CBN), and wurtzite boron nitride (WBN).

Boron nitride was introduced over 100 years ago, with its earliest application being hexagonal boron nitride as a high-temperature lubricant. Its structure and properties are very similar to graphite, and it is also pure white, hence it is commonly known as "white graphite".

Boron nitride (BN) ceramics were discovered as early as 1842. Extensive research on BN materials has been conducted abroad since World War II, and it was not until 1955 that the BN hot pressing method was developed. The American Diamond Company and United Carbon Company were the first to enter production, producing over 10 tons by 1960.

In 1957, R.H. Wentrof was the first to successfully develop CBN. In 1969, General Electric sold it as Borazon, and in 1973, the United States announced the production of CBN cutting tools.

In 1975, Japan imported technology from the United States and also prepared CBN cutting tools.

In 1979, pulsed plasma technology was successfully used for the first time to prepare brittle BN thin films at low temperature and low pressure.

In the late 1990s, people were able to prepare c-BN thin films using various physical vapor deposition (PVD) and chemical vapor deposition (CVD) methods.

From a domestic perspective in China, development has made rapid progress. Research on BN powder began in 1963, was successfully developed in 1966, and was put into production and applied in China's industry and cutting-edge technology in 1967.

Material characteristics:

CBN is usually a black, brown, or dark red crystal with a sphalerite structure and good thermal conductivity. Hardness second only to diamond, it is a superhard material commonly used as a tool material and abrasive.

Boron nitride has chemical resistance and is not corroded by inorganic acids and water. The boron nitrogen bond is broken in hot concentrated alkali. Oxidation begins in the air above 1200 ℃. Decomposition begins at around 2700 ℃ under vacuum. Slightly soluble in hot acid, insoluble in cold water, with a relative density of 2.29. The compressive strength is 170MPa. The maximum operating temperature under oxidizing atmosphere is 900 ℃, while it can reach 2800 ℃ under non reactive reducing atmosphere, but the lubrication performance is poor at room temperature. Most of the properties of boron nitride are superior to 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 electrical resistivity, corrosion resistance, microwave or infrared transparency.

Material structure:

Boron nitride hexagonal crystal system, most commonly graphite lattice, also has amorphous variants. In addition to the hexagonal crystal form, boron nitride has other crystal forms, including rhombohedral boron nitride (r-BN), cubic boron nitride (c-BN), and wurtzite type boron nitride (w-BN). People have even discovered two-dimensional boron nitride crystals that resemble graphite thin.

The commonly produced boron nitride has a graphite type structure, commonly known as white graphite. Another type is diamond type, which is similar to the principle of graphite transforming into diamond. Graphite type boron nitride can be transformed into diamond type boron nitride at high temperature (1800 ℃) and high pressure (8000Mpa) [5-18GPa]. It is a new type of high-temperature resistant superhard material used for making drill bits, grinding tools, and cutting tools.

Application areas:

1. Mold release agents for metal forming and lubricants for metal drawing.

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

3. High temperature solid lubricants, extrusion anti-wear additives, additives for producing ceramic composite materials, refractory materials and antioxidant additives, especially for applications that resist molten metal corrosion, thermal enhancement additives, and high-temperature resistant insulation materials.

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

5. Pressed into various shapes of boron nitride products, which can be used as high-temperature, high-voltage, insulation, and heat dissipation components.

6. Thermal shielding materials in aerospace.

7. With the participation of a catalyst, it can be converted into cubic boron nitride that is as hard as diamond through high-temperature and high-pressure treatment.

8. Structural materials of atomic reactors.

9. Jet nozzles for aircraft and rocket engines.

10. Insulators for high-voltage, high-frequency electrical and plasma arcs.

11. Packaging materials that prevent neutron radiation.

12. A superhard material processed from boron nitride, which can be used to make high-speed cutting tools and drill bits for geological exploration and oil drilling.

13. Separation rings used in metallurgy for continuous cast steel, flow slots for amorphous iron, and release agents for continuous cast aluminum.

14. Make evaporation boats for various capacitor film aluminum plating, cathode ray 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 aluminum plating, and so on.

17. Cosmetics are used as fillers for lipstick, which are non-toxic, lubricating, and glossy.