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| Synonyms:Tetraboron carbide Black Diamond Boron carbide ceramic Boron carbide powder Molecular Formula:B₄C Molecular Weight: 55.25 HS Code: 2849901000 Grade:Grinding grade (Industrial grade 97%) Sintering grade 98% Nano-grade Hazard Class:General Cargo | |||||||||
12069-32-8
Boss Chemical
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 substance (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).
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). The boron-10 (10B) isotope has an absorption cross-section for thermal neutrons as high as approximately 3837 eV, and after capturing neutrons, it only produces short-lived lithium and helium. 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 oxidizers.
From the perspective of its mechanism of action, industrial-grade boron carbide plays an irreplaceable role due to the combination of "ultra-high hardness + low density + neutron absorption + semiconductor properties". 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).
The combination of high hardness and fracture toughness of about 3.5 MPa·m1/2 makes boron carbide ceramics wear very slowly under high-speed abrasive erosion, making them suitable for strong erosion conditions such as sandblasting nozzles and waterjet nozzles.
With a melting point of approximately 2350℃ and high high-temperature strength, the B2O3 glass phase generated by oxidation at high temperatures can seal pores and prevent oxygen. When added to refractory materials such as magnesia-carbon bricks, it can significantly improve thermal shock resistance and slag erosion resistance.
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 approximately 2.09 eV. Its electrical conductance is mainly characterized by hopping transport. It maintains semiconductor behavior at high temperatures and can be used in the research of high-temperature thermoelectric materials and electronic functional devices.
Boron carbide has a high boron content, and the combustion of boron releases a large amount of heat and the combustion rate is adjustable. As a boron-based high-energy fuel component for solid fuel ramjet engines, it can significantly improve the fuel energy density.
Application Field: abrasives and precision machining.
Corresponding Products: Boron carbide grinding powder, polishing powder, grinding paste and 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 lower 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 high-pressure airflow or water flow, they repeatedly impact workpiece surfaces with low wear and strong cutting force, suitable for rust removal, deburring and cutting hard and brittle materials.
Application Field: Fluid processing and processing equipment.
Corresponding Products: Sandblasting nozzles, waterjet cutting nozzles, wear-resistant sealing rings, wear-resistant bearings, wear-resistant liners, pump and valve wear parts, erosion protection sleeves and others.
Applicability Principle: The high hardness of boron carbide ceramic combined with a fracture toughness of approximately 3.5 MPa·m1/2 provides extremely strong resistance to abrasive erosion and wear, significantly extending the service life of nozzles and wear parts.
Application Field: Composite materials and lightweight structures.
Corresponding Products: Boron carbide reinforced aluminium matrix composites (B₄C/Al), boron carbide filament reinforced resin and metal composites, armour composites, high-end bicycle and sports equipment components etc.
Applicability Principle: Boron carbide particles and fibres have high modulus, high strength and low density. They can be combined with matrices like aluminium to increase stiffness, wear resistance and ballistic properties while reducing weight.
Application Field: Automotive brake and gearbox friction materials.
Corresponding Products: Brake linings (brake pads), clutch friction plate, brake shoes, friction material additives, high performance brake disc formulations etc.
Applicability Principle: Boron carbide has high hardness, wear resistance, stable coefficient of friction and high temperature resistance, which can improve the wear life of friction materials and high-temperature braking stability.
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: Cutting, 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, etc.
Applicability Principle: Boron carbide features ultra-high hardness and thermal stability. Used as cutting tool material or coating, it can withstand high-temperature wear during high-speed cutting, suitable 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 delivers anti-oxidation 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 crucibles, Thermocouple protection tubes, High temperature insulating parts, Vacuum evaporation boats, High temperature furnace parts, High temperature resistant fixtures, etc.
Applicability Principle: Boron carbide has a high melting point, good thermal stability, thermal shock resistance and chemical corrosion resistance, and can operate for long periods under harsh high-temperature environments.
Application Field: Electronic functional materials and semiconductors.
Corresponding Products: P-type Semiconductor Materials, Boron Doped Semiconductor Materials, Neutron Detectors, High Temperature Thermoelectric Material, Electronic Ceramic Functional Components, Scientific Research Single Crystal and Thin Film Materials, etc.
Applicability Principle: Boron carbide is a P-type semiconductor with a band gap of about 2.09 eV. It functions as a high-temperature semiconductor, and boron-10 is neutron-sensitive. It is useful for high-temperature electronic devices and neutron detection applications.
To summarise, industrial-grade boron carbide (CAS 12069-32-8) is the “King of Hardness and Shield of Neutrons”. The ultrahigh hardness, low density, neutron absorption, and semiconductor properties of this material support its applications across multiple fields: grinding and polishing abrasives, sandblasting and waterjet 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. Among these, grinding abrasives represent the largest and most representative consumption area.
