Molecular Formula | BN |
Molar Mass | 24.82 |
Density | 0.9-1.1 g/mL at 25 °C |
Melting Point | 2700℃ |
Boling Point | sublimes sl below 3000℃ [MER06] |
Water Solubility | Soluble in water (slightly soluble) at 20°C, and water (soluble) at 95°C. |
Solubility | Insoluble in cold water, slightly soluble in hot acid. |
Appearance | White powder |
Specific Gravity | 3.48 |
Color | White |
Merck | 14,1346 |
PH | 5-8 (100g/l, H2O, 20℃)(slurry) |
Storage Condition | no restrictions. |
Stability | Stable. Incompatible with oxidizing agents, water. |
Sensitive | Hygroscopic |
MDL | MFCD00011317 |
Physical and Chemical Properties | Character white loose powder. relative density 2.25 solubility insoluble in cold water, slightly soluble in hot acid. |
Use | Used to make refractory materials, furnace insulation materials, but also used in electronics, machinery, aviation and other industries |
Hazard Symbols | Xi - Irritant |
Risk Codes | 36/37 - Irritating to eyes and respiratory system. |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36 - Wear suitable protective clothing. |
UN IDs | UN1950 |
WGK Germany | 3 |
RTECS | ED7800000 |
TSCA | Yes |
HS Code | 2850 00 20 |
Hazard Class | 2.1 |
Toxicity | LD50 orally in Rabbit: > 2000 mg/kg LD50 dermal Rat > 2000 mg/kg |
Raw Materials | Nitrogen Urea Orthoboric acid Melamine Ammonia |
Reference Show more | 1. Chen Can, Yu Huitao, Feng Yiyu, Feng Wei. Polymer composites with thermal conductivity and self-healing functions [J]. Journal of Polymer Science, 2021,52(03):272-280. |
boron nitride (BN) ceramics have hexagonal and cubic structures. The crystal structure of hexagonal boron nitride has a similar graphite layered structure, showing a loose, lubricating, easy to absorb moisture, light and other properties of white powder, so also known as "white graphite". The theoretical density is 2.27g/cm3; And the Mohs hardness is 2. Hexagonal boron nitride is well-bred for electrical insulation, thermal conductivity, chemical stability; No apparent melting point, at 0. IMPa in nitrogen 3000 ° C sublimation, in the inert gas melting point of 3000 ° C, in a neutral reducing atmosphere, heat resistance to 2000 ° C, in nitrogen and argon in the use of temperature up to 2800 ° C, the stability is poor in an oxygen atmosphere, and the use temperature is 1000 ° C. Or lower. Hexagonal boron nitride does not dissolve in cold water, water boiling hydrolysis is very slow and produce a small amount of boric acid and ammonia; With weak acid and strong alkali at room temperature are not reacted, slightly soluble in hot acid, with molten sodium hydroxide, potassium hydroxide treatment can be decomposed. Hexagonal boron nitride has an expansion coefficient equivalent to that of quartz, but its thermal conductivity is 10 times higher than that of quartz. BN is both a good conductor of heat and an electrical insulator. Its breakdown voltage is 4 to 5 times that of alumina, and its dielectric constant is 1/2 of that of alumina. The performance of BN is stable under ultra high pressure, and BN is the lightest ceramic material. Cubic BN is sphalerite structure, high chemical stability, good thermal conductivity and heat resistance, and its hardness is similar to that of artificial diamond. It is an excellent abrasive material. Its most prominent advantage over diamond is that it does not react with ferrous metals at high temperatures and can be used at a temperature of 1400 °c.
Common methods for synthesis of boron nitride include boron anhydride method, boron halide method, boric acid method, Borax method, arc plasma method, etc. The boron anhydride method is the main method of industrial production of boron nitride. The commonly produced boron nitride is graphite-type Hexagonal boron nitride, which can be converted into diamond-type cubic boron nitride at high temperature (1800 ° C.) and high pressure (800MPa).
hexagonal boron nitride has a layered crystal structure similar to graphite, and has good lubricity and thermal conductivity. Hexagonal boron nitride is also a raw material for synthesizing cubic boron nitride. Cubic boron nitride has excellent physical and chemical properties, the hardness is second only to diamond. Cubic boron nitride is mainly used as advanced refractory materials, super hard wear-resistant materials, made of boron nitride processing of super hard materials, can be made into high-speed cutting tools and geological exploration, oil drilling bit. Because cubic boron nitride also has high thermal conductivity and good semiconductor characteristics, it is also a semiconductor material with high temperature, and is widely used in the fields of optoelectronics and microelectronics. In addition, boron nitride can be used in the manufacture of TiB2 /BN composite ceramics, metal forming mold release agent and metal wire drawing lubricant and high temperature coating, in the case of resistance to molten metal corrosion as a thermal enhancement additive, high temperature resistant insulating materials. Used as a semiconductor silicon doping source. In aviation and other industries, it can be used as heat shielding materials in aerospace, structural materials for atomic reactors, high-voltage high-frequency electric and plasma arc insulators.
packed in polyethylene plastic bags. 1kg net weight of each bag. Should be stored in a well-ventilated dry warehouse to prevent moisture. Transport should be packed in wooden boxes, so as not to damage moisture.
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
Cubic boron nitride and hexagonal boron nitride | Boron nitride is a crystal composed of nitrogen atoms and boron atoms. The crystal structure is divided into: hexagonal boron nitride (HBN), densely packed hexagonal boron nitride (WBN) and cubic boron nitride, the crystal structure of hexagonal boron nitride has a similar graphite layered structure, white powder with loose, lubricated, easy moisture absorption, light weight and other properties, so it is also called "white graphite". The expansion coefficient of hexagonal boron nitride is equivalent to quartz, but the thermal conductivity is ten times that of quartz. It also has good lubricity at high temperatures. It is an excellent high-temperature solid lubricant with strong neutron absorption capacity, stable chemical properties, and chemical inertness to almost all molten metals. hexagonal boron nitride is insoluble in cold water. When the water is boiled, it hydrolyzes very slowly and produces a small amount of boric acid and ammonia. It does not react with weak acids and strong bases at room temperature. It is slightly soluble in hot acids and is treated with molten sodium hydroxide and potassium hydroxide to decompose. It has considerable corrosion resistance to various inorganic acids, alkalis, salt solutions and organic solvents. Cubic boron nitride is a kind of superhard material with hardness second only to diamond. It was first developed by R.H. Wintov of the United States in 1957. It not only has many excellent characteristics of diamond, but also has higher thermal stability and chemical stability to iron group metals. Widely used in processing hardened steel, chilled cast iron, heat-resistant alloy and other ferrous metals. |
use | used to make refractory materials, furnace insulation materials, and also used in electronics, machinery, aviation and other industries boron nitride has a variety of excellent properties, widely used in high-voltage, high-frequency electric and plasma arc insulators, coatings for automatic welding high-temperature resistant frames, materials for high-frequency induction furnaces, solid-phase admixtures for semiconductors, structural materials for atomic reactors, packaging materials to prevent neutron radiation, Radar transmission windows, radar antenna media and rocket engine components, etc. Due to its excellent lubricating properties, it is used as a high-temperature lubricant and a release agent for various models. Molded boron nitride can be used to manufacture high temperature resistant crucibles and other products. It can be used as a superhard material, suitable for drill bits and high-speed cutting tools for geological exploration, oil drilling. It can also be used as a metal processing abrasive material, which has the characteristics of low processing surface temperature and few surface defects of parts. Boron nitride can also be used as an additive for various materials. The boron nitride fiber made from boron nitride processing is a medium modulus high functional fiber. It is an inorganic synthetic engineering material that can be widely used in the chemical industry, textile industry, aerospace technology and other cutting-edge industrial sectors. Metal molding release agent and metal wire drawing lubricant; special electrolysis and resistance materials at high temperatures; solid lubricants; heat-sealing desiccant for transistors and polymer additives such as plastic resins; pressed into various shapes Boron nitride products can be used as high temperature, high pressure, insulation, and heat dissipation components; heat shielding materials in the aerospace industry; with the participation of catalysts, after high temperature and high pressure treatment, it can be converted into cubic boron nitride that is hard as diamond. |
production method | boron trichloride ammonia vapor deposition method fully mixes the prepared boron trichloride and hydrogen together with ammonia heated to a certain temperature, and reacts in the reactor at the specified required reaction temperature, and then at a higher temperature, continue heating in the ammonia gas stream for a certain period of time to produce boron nitride finished products. Its BCl3 2NH3 → BN 2HCl NH4Cl borax ammonium chloride method dehydrates borax at 450 ℃ and pressure of 79993 Pa. Ammonium chloride is dried at 110~120 ℃ in advance and crushed to 40 mesh fineness respectively. According to the mass ratio of anhydrous borax and ammonium chloride of 1:0.59, the ingredients are mixed and pressure molded. Then, it is sent to the reactor, and excessive ammonia is introduced into the reactor, and the reaction is carried out at 1050°C to generate coarse boron nitride crystals. After crushing, sieving, washing, filtering, and drying, the finished boron nitride product is prepared. It Na2B4O7 the manufacture of 2NH4Cl 2NH3 → 4BN 2NaCl 7H2O cubic crystal boron nitride. It can be prepared by reacting under high pressure and high temperature with the addition of lithium hydride powder additives as raw materials. |