Boron carbide chemical formula B4C. Glossy black crystals with a relative density of 2.52, a melting point of 2350 ° C, and a boiling point above 3500 ° C. Chemically stable, insoluble in water and various acids, soluble in molten alkali. Harder than diamond but higher than silicon carbide, Mohs hardness is 9.3. High thermal neutron capture ability, wear resistance, and semiconductor conductivity. The general requirements for product quality are that the abrasive grains contain B4C not less than 94%, and the abrasive powders not less than 90%. . Boron carbide is widely used in the grinding and polishing of gemstones because of its excellent properties. Sapphire is the most ideal substrate material for practical applications such as semiconductor GaN / Al2O3 light-emitting diodes (LEDs), large-scale integrated circuits SOI and SOS, and superconducting nanostructured thin films. Sapphire wafers as LED substrates require a high degree of smoothness on the surface, which must be ultra-smooth without damage. The quality of the device mainly depends on the surface processing technology of the substrate. Grinding is a key part of the sapphire industry. Abrasives have a greater impact on sapphire grinding and chemical mechanical polishing. At present, boron carbide has gradually replaced diamond abrasive as a sapphire abrasive, greatly reducing the cost of the grinding process. According to statistics, China's sapphire industry produced more than 3,000 tons of grinding waste in 2012 alone. At present, there is little research on boron carbide recycling in China. As the amount of sapphire increases, the demand for boron carbide for grinding will continue to increase, and the resulting grinding waste will increase accordingly. Therefore, the recovery of boron carbide from grinding waste is a very interesting research direction.

What is the properties of boron carbide powder?

      (1) The most important property of boron carbide is its extraordinary hardness (Mohs hardness is 9.3), which is second only to diamond and cubic boron nitride. It is the most ideal high-temperature wear-resistant material;
     (2) The density of boron carbide is very small, it is the lightest among ceramic materials, and can be used in the aerospace field;
     (3) Boron carbide has a strong neutron absorption capacity. Compared with pure elements B and Cd, it has low cost, good corrosion resistance, and good thermal stability. It is widely used in the nuclear industry. Further improvement by adding B element;
      (4) The chemical properties of boron carbide are excellent. It does not react with acids, alkalis and most inorganic compounds at room temperature. It has slow corrosion only in the mixture of hydrofluoric acid, sulfuric acid and hydrofluoric acid, nitric acid. One of the compounds
      (5) Boron carbide also has the advantages of high melting point, high elastic modulus, low expansion coefficient, and good oxygen absorption capacity;
      (6) Boron carbide is also a p-type semiconductor material, which can maintain semiconductor characteristics even at very high temperatures.