Low-temperature Hexagonal Boron Nitride

Product Introduction

Chinese Name: Low-temperature Hexagonal Boron Nitride

Also known as: Boron Nitride, White Graphite

English Name: Hexagonal Boron Nitride

Chemical Formula: BN

Molecular Weight: 24.82

Main Purity: ≥97%; ≥99%

Quality Standard: Q/LNPD2023-101

CAS No.: 10043-11-5

HS Code: 2850001200

The company is one of the few manufacturers in China that produces both high-temperature boron nitride and low-temperature boron nitride. Low-temperature boron nitride is synthesized in a reaction furnace by mixing borax and ammonium chloride at a reaction temperature of 1000–1200°C. High-temperature boron nitride is prepared by mixing boric acid and melamine, followed by high-temperature calcination at 1700°C.

Product Features

▶ Boron nitride is a crystal composed of nitrogen and boron atoms. Its crystal structures are divided into three types: hexagonal boron nitride (HBN), wurtzite boron nitride (WBN) and cubic boron nitride. Among them, hexagonal boron nitride features a graphite-like layered crystal structure. It is a white powder with loose texture, lubricity, easy moisture absorption and light weight, hence also known as "white graphite".

▶ Theoretical density: 2.27 g/cm³; specific gravity: 2.43; Mohs hardness: 2.

▶ Hexagonal boron nitride possesses excellent electrical insulation, thermal conductivity and chemical stability. It has no obvious melting point. It can withstand temperatures up to 3000 ℃ in nitrogen atmosphere at 0.1 MPa, up to 2000 ℃ in neutral reducing atmosphere, and up to 2800 ℃ in nitrogen or argon. It exhibits poor stability in oxygen atmosphere, with a service temperature below 1000 ℃.

▶ The thermal expansion coefficient of hexagonal boron nitride is equivalent to that of quartz, while its thermal conductivity is ten times higher. It maintains good lubricity at high temperatures and serves as an excellent high-temperature solid lubricant. It has strong neutron absorption capacity, stable chemical properties, and chemical inertness to almost all molten metals.

▶ Hexagonal boron nitride is insoluble in cold water. It hydrolyzes very slowly in boiling water, generating a small amount of boric acid and ammonia. It does not react with weak acids or strong alkalis at room temperature, and is slightly soluble in hot acids. It can only be decomposed by treatment with molten sodium hydroxide or potassium hydroxide. It has considerable corrosion resistance to various inorganic acids, alkalis, salt solutions and organic solvents.

Boron Nitride Parameters

▶ High heat resistance: It sublimes at 3000°C. Its strength at 1800°C is twice that at room temperature. It remains intact without cracking after dozens of air-cooling cycles from 1500°C to room temperature, and does not soften up to 2800°C in an inert atmosphere.

▶ High thermal conductivity: Hot-pressed products reach 33 W/(m·K), equivalent to pure iron. Above 530°C, it ranks among the highest thermal conductivity values among ceramic materials.

▶ Low thermal expansion coefficient: Its expansion coefficient is 2×10^-6, second only to fused silica and one of the lowest among ceramics. Combined with high thermal conductivity, it delivers excellent thermal shock resistance.

▶ Superior electrical properties: Outstanding high-temperature insulation. Resistivity is 1014Ω-cm at 25°C and still reaches 103Ω-cm at 2000°C, making it one of the best high-temperature insulating ceramics. Breakdown voltage: 3 kV/mm; low dielectric loss of 2.5×10^-4 at 108HZ; dielectric constant of 4. It is transparent to microwaves and infrared rays.

▶ Excellent corrosion resistance: It is chemically inert to common metals (iron, copper, aluminum, lead, etc.), rare earth metals, precious metals, semiconductor materials (germanium, silicon, gallium arsenide), glass, molten salts (cryolite, fluorides, slag), and inorganic acids and alkalis.

▶ Low friction coefficient: The friction coefficient μ is 0.16 and does not rise at high temperatures. It withstands higher temperatures than molybdenum disulfide and graphite. Service temperature up to 900°C in oxidizing atmosphere and up to 2000°C in vacuum.

▶ High purity: Impurity content is less than 10 PPM, while boron content is over 43.6%.

▶ Good machinability: With a Mohs hardness of 2, it can be processed into high-precision parts using conventional mechanical machining methods.

Technical Indicators

Application Scope

▶ Boron nitride is a non-toxic, high-temperature resistant, corrosion-resistant material featuring high thermal conductivity, superior electrical insulation and excellent lubricating properties.

▶ It serves as both an electrical insulator and a thermal conductor. It is an ideal material for special electrolysis and resistance applications under high temperatures, as well as an insulator for high-voltage, high-frequency electricity and plasma arcs.

▶ It can be used as a solid-phase doping material for semiconductors and as antioxidant or waterproof lubricating grease.

▶ It is widely used as a high-temperature lubricant and mold release agent. Boron nitride powder can also act as an anti-sticking agent for glass beads and a release agent for glass and metal forming processes.

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

▶ It can be used as structural materials for atomic reactors, nozzles for aircraft and rocket engines, packaging materials for preventing neutron radiation, and thermal shielding materials in aerospace applications.

▶ Non-toxic, harmless and lubricious, it can be used as a filler in cosmetics.

▶ Under the action of a catalyst and treatment with high temperature and high pressure, it can be converted into cubic boron nitride, which is as hard as diamond.

▶ It is applied to evaporation boats for aluminum coating of various capacitor films, picture tubes and displays.

▶ It can be used as heat-sealing desiccants for transistors and additives for polymers such as plastic resins.

▶ It is suitable for aluminum coating of various laser anti-counterfeiting materials, trademark hot stamping materials, cigarette labels, beer labels, packaging boxes, cigarette packaging boxes and more.

▶ Used in silicon carbide rods to enhance resistance strain performance.

▶ Used as a coolant additive.

▶ Boron nitride is applied in polymorphs, paints, dental cements and pencil leads. It is also used in electrostatic printing and laser printers as a charge leakage barrier layer for photosensitive drums, as well as a filler and processing aid.

Packaging Method

1kg per aluminum foil bag

5kg per aluminum foil bag

10kg per carton

20kg per carton