Exploring the Mysteries of Boron Nitride - The 'Magician' of Materials at High Temperatures

Hexagonal boron nitride is a crystal composed of nitrogen and boron atoms, with a molecular formula of BN and a molecular weight of 24.81. Its chemical composition consists of 43.6% boron and 56.4% nitrogen, and it has a theoretical density of 2.27 g/cm³. Boron nitride (BN) includes five isomers: hexagonal boron nitride (h-BN), wurtzite boron nitride (w-BN), rhombohedral boron nitride (r-BN), cubic boron nitride (c-BN), and orthorhombic boron nitride (o-BN). As a novel ceramic material with excellent properties and significant growth potential, it is widely used in the fields of machinery, metallurgy, chemical engineering, electronics, nuclear energy, and aerospace. BN powder exhibits properties such as looseness, lubrication, Lightweight, and ease of moisture absorption. The most common forms are hexagonal boron nitride (h-BN) and cubic boron nitride (c-BN).

Cubic Boron Nitride: The Brilliant Star of Superhard Materials

Cubic Boron Nitride (c-BN) was first synthesized artificially under high temperature and pressure conditions by General Electric (GE) in the United States in the 1950s. Its hardness is second only to diamond and far exceeds that of other materials. The unique value of c-BN mainly lies in its chemical inertness towards iron group metals. At a high temperature of 1300°C, c-BN can still maintain stability.

In addition, c-BN also possesses several excellent properties:

High thermal conductivity:which is beneficial for heat dissipation during the cutting process.

High resistivity: allowing it to be used as an insulating heat dissipation material.

The properties of cubic boron nitride:The structure is stable, possesses high antioxidant capability, and exhibits good chemical stability, making it particularly suitable for processing black metal materials; its thermal conductivity is lower than that of diamond but higher than that of hard alloys, demonstrating good thermal conductivity; it has high flexural strength; as a grinding material, it has a long service life and excellent Wear Resistance.

Hexagonal Boron Nitride: The Structural Secrets of White Graphene

Hexagonal boron nitride (h-BN), due to its structural characteristics similar to graphite, is known as "white graphene." In its crystal structure, boron (B) atoms and nitrogen (N) atoms form a honeycomb hexagonal planar network through strong covalent bonds, while the layers are held together by weak van der Waals forces. This material is widely used in fields such as high-temperature lubricants and Ceramic Composites.

The characteristics of hexagonal boron nitride (h-BN) are as follows:

Chemical Inertness:

h-BN is inert to general metals, rare metals, precious metals, semiconductor materials, glass, molten salts, inorganic acids, and bases. It does not wet or react with most molten alloys, such as steel, stainless steel, aluminum, iron, germanium, copper, nickel, and zinc. Therefore, h-BN can be used as a crucible for melting metals, containers, pipes for transporting molten metals, pump components, molds for casting steel, and high-temperature electrical insulation materials.

High Temperature Stability:

h-BN can withstand high temperatures of 900°C in air and remains stable up to 2000°C in an inert environment, making it suitable for high-temperature forming processes such as metal casting and ceramic sintering, without decomposing or failing due to high temperatures.

Excellent lubrication properties:

The layered structure of hexagonal boron nitride imparts excellent lubricating and release (i.e., anti-stick) properties, making it suitable for use as a release agent in the casting of precision parts and non-ferrous metal castings, as well as in the thermal forming process of sheet metal. It can reduce friction between the material and the mold, protect the surface of the mold, extend its lifespan, and effectively improve the surface quality of the products.

The application fields of hexagonal boron nitride

Hexagonal boron nitride (h-BN) maintains excellent lubrication performance at high temperatures and can be used as a lubricant for sliding parts in high-temperature furnaces, wear-resistant coatings, and contact materials. This includes separating coatings, washing devices, ladles, automatic pouring molds, various troughs and pipes, funnels, chutes and nozzles, filtering bowls, filter boxes, casting machine blades, slag pressing heads, electric heating elements, as well as splash release for welding/soldering spatter and suppression of brazing/anti-solder agents. Additionally, it provides an ideal solution for high-temperature demolding and lubrication in the manufacturing process of aluminum extrusions.