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12069-32-8
futurechemical
12069-32-8
Boron carbide (chemical formula B4C, commonly known as black diamond, CAS 12069-32-8) is a covalently bonded superhard ceramic material composed of boron and carbon. It is a dark gray to black, odorless powder. It is the third hardest known material (after diamond and cubic boron nitride), with a Mohs hardness of 9.5-9.75 and a Vickers hardness of approximately 38 GPa, hence its nickname "black diamond."
Basic identification information: Molecular formula B4C (actual structure is a complex rhombohedral structure with B12 icosahedron as the framework; ideal formula can also be written as B12C3, but actual products are usually slightly lacking in carbon), molecular weight 55.255, CAS number 12069-32-8, PubChem CID 123279, UNII T5V24LJ508, ECHA InfoCard 100.031.907; Industrially, it is mainly produced by carbothermal reduction in an electric arc furnace at temperatures above 2000℃ (2B2O3 + 7C → B4C + 6CO), and can also be produced by magnesium reduction (byproducts are removed by acid washing). The coarse powder is crushed, acid washed, purified, and graded to obtain products of different grades.
Physically, it is a dark gray to black powder, odorless; density is about 2.50 g/cm³ (lighter than silicon carbide and alumina); melting point is about 2350℃ (boiling point is above 3500℃); insoluble in water, stable to ionizing radiation and most chemicals; crystals are rhombohedral (space group R3m).
In terms of chemical properties and functional characteristics, boron carbide is a covalent compound with strong chemical inertness and resistance to acid and alkali corrosion. It hardly reacts with any common reagents at room temperature. At high temperatures, it can be oxidized (forming a boron trioxide (B₂O₃) glassy phase on the surface, which can actually seal the pores and protect the substrate). It is also a typical p-type semiconductor with a band gap of approximately 2.09 eV. Storage requires protection from moisture and dust, and away from fire and oxidants.
From the perspective of its mechanism of action, boron carbide plays an irreplaceable role due to the combination of "ultra-high hardness + low density + neutron absorption + semiconductivity". The mechanism of action in different applications is as follows:
Boron carbide has a Mohs hardness of 9.5-9.75 and a Vickers hardness of about 38 GPa, second only to diamond and cubic boron nitride. Its particles have sharp cutting edges and good self-sharpening properties, and can grind and polish materials that are harder than it (such as cemented carbide, sapphire, and diamond).
Submicron to micron fine powders have a large specific surface area, high surface energy, and short diffusion path. They can be densified through grain boundary diffusion under pressureless, hot-pressed, or SPS conditions to obtain boron carbide ceramics with near-theoretical density.
The combination of high hardness and fracture toughness of approximately 3.5 MPa·m1/2 makes boron carbide wear extremely slowly under high-speed abrasive erosion, making it suitable for high-erosion conditions such as nozzles, seals, and wear-resistant liners.
With a melting point of approximately 2350℃ and high high-temperature strength, the B2O3 glass phase generated by high-temperature oxidation seals pores and inhibits oxygen. When added to refractory materials or made into high-temperature components, it can serve for a long time in harsh high-temperature environments.
Boron carbide particles and fibers have high modulus, high strength, and low density. When combined with metals such as aluminum or resins, they can simultaneously improve stiffness, wear resistance, and lightweighting, making them a reinforcing phase for armor and structural components.
Boron carbide is a p-type semiconductor with a band gap of about 2.09 eV. It retains its semiconductor behavior at high temperatures and can be used in high-temperature thermoelectric materials. At the same time, it has a high boron content and a large heat release during boron combustion, making it a boron-based high-energy component of solid fuel for ramjet engines.
Application Field: Abrasives & Precision Machining.
Corresponding Products: Boron Carbide Grinding Powder, Polishing Powder, Grinding Paste and Slurry, Nano Level Polishing Slurry, Gemstone Cutting Abrasives, Diamond & Gemstone Processing Abrasives, Optical Glass Abrasives, Cemented Carbide Abrasives, Sapphire Substrate Abrasives, Precision Bearing Abrasives, etc.
Applicability Principle: Boron carbide, with a Mohs hardness rating of 9.5 to 9.75, is the third hardest known material after diamond and cubic boron nitride. Its particles have sharp cutting edges with good self-sharpening properties and are effective for grinding and polishing materials of equal or higher hardness. It serves as the mainstream abrasive for precision grinding and polishing at a lower cost than diamond.
Application Field: Water jet cutting and surface treatment.
Corresponding Products: Sandblasting and rust removing abrasives, waterjet cutting abrasives, vibratory finishing abrasives, shot blasting abrasives, stone cutting abrasives, metal surface treatment abrasives etc.
Applicability Principle: Boron carbide particles possess high hardness and good toughness. Under repeated impact on workpiece surfaces driven by high-pressure airflow or water flow, they show low wear and strong cutting force, suitable for rust removal, deburring and cutting hard and brittle materials.
Application Field: Machining and fluid systems.
Corresponding Products: Sandblasting nozzles, waterjet cutting nozzles, wear resistant sealing rings, mechanical seals, wear resistant bearings, wear resistant liners, pump and valve wear parts, erosion protection sleeves, coal mill wear parts, etc.
Applicability Principle: Sintered boron carbide ceramic features high hardness and fracture toughness of approximately 3.5 MPa·m$^{(^{1/2})}$, delivering excellent abrasive erosion and wear resistance, which greatly extends the service life of nozzles and wear components.
Application Field: Composite materials and lightweight structures.
Corresponding Products: Aluminium matrix composites reinforced by boron carbide (B₄C/Al), powder metallurgy aluminium matrix composites, boron carbide wire reinforced resin and metal composites, armour composites, components for high-end bicycles and sports equipment, light-weight automotive parts etc.
Applicability Principle: Boron carbide particles and fibres are high-strength, high-stiffness and lightweight. When combined with matrices like aluminium, they increase stiffness, wear resistance and ballistic properties while reducing overall weight.
Application Field: Automotive Brake and Transmission Friction Materials
Corresponding Products: Brake Pads, High Performance Ceramic Brake Pads, Clutch Friction Plates, Brake Shoes, Friction Material Additives, Heavy Duty Vehicle Brake Pads, Motorcycle Brake Pads etc.
Applicability Principle: Boron carbide has high hardness, wear resistance, stable friction coefficient and high temperature resistance, which can improve the wear life and high-temperature braking stability of friction materials.
Application Field: Surface Coating and Protection Engineering
Corresponding Products: Chemical vapour deposition (CVD) boron carbide coatings, plasma spraying coatings, wear-resistant coatings, scratch-resistant coatings, mould coatings, wear-resistant coatings for mechanical parts, watch cases, electronic product surface coatings, etc.
Applicability Principle: Boron carbide coatings are extremely hard, wear resistant, heat resistant and chemically inert, providing excellent scratch and wear protection for the surfaces of cutting tools, moulds and finished products.
Application Field: Die-cutting and die-making. Corresponding Products: Boron Carbide Ceramic cutting tools, Cemented carbide cutting tools, Stamping dies, Wire drawing dies, Extrusion dies, Grinding wheels and abrasives, Wear-resistant parts for drills and milling cutters, Gear hobbing tools, etc.
Applicability Principle: Boron carbide features ultra-high hardness and thermal stability. Used as cutting tool material or coating, it resists high-temperature wear during high-speed cutting, so it is applicable for machining hard, brittle and difficult-to-cut materials.
Application Field: Iron and steel metallurgy and high temperature kilns
Corresponding Products: Magnesia-carbon bricks, refractory castables, monolithic refractories, high temperature furnace linings, ladle and converter refractories etc.
Applicability Principle: The melting point of boron carbide is around 2350℃ with high high-temperature strength. It provides antioxidation and anti-slag erosion performance. When added to refractory materials, it improves thermal shock resistance and extends the service life of furnace linings.
Application Field: High temperature melting and temperature measuring devices.
Corresponding Products: Boron carbide ceramic crucibles, thermocouple protection tubes, high-temperature insulation components, vacuum evaporation boats, high-temperature furnace components, high-temperature resistant clips, smelting refractory components, etc.
Applicability Principle: Boron carbide has a high melting point, good thermal stability, thermal shock resistance and chemical corrosion resistance, and can be used for long periods of time in harsh high temperature environments.
Application Field: Semiconductor and electronic functional materials
Corresponding Products: p-type semiconducting material, boron doped semiconductor source, neutron detector, high temperature thermoelectric ceramics, electronic ceramic functional parts, single crystal and thin film materials for scientific research etc.
Applicability Principle: Boron carbide is a p-type semiconductor with a band gap of about 2.09 eV and retains semiconductor behaviour at high temperatures. Boron-10 is neutron-sensitive, which makes it suitable for high-temperature electronic devices and neutron detection applications.
Summarize boron carbide (CAS 12069-32-8), the "King of Hardness and Shield of Neutrons". Its ultra high hardness, low density and semiconductor properties make it suitable for a wide range of applications such as grinding and polishing abrasives, sandblasting and water jet abrasives, wear resistant nozzles and erosion protection, metal matrix composites, vehicle friction materials, wear resistant and scratch resistant coatings, cutting tools and moulds, refractory additives, high temperature structural ceramic parts, semiconductor and electronic functional materials and high energy fuels for ramjet engines. The largest and most representative area of consumption is grinding and polishing abrasives.
