What Is Boron Nitride Ceramic
Boron nitride is a crystal composed of nitrogen atoms and boron atoms. The chemical composition is 43.6% boron and 56.4% nitrogen, with four different variants: hexagonal boron nitride (HBN), rhombohedral boron nitride (RBN), cubic boron nitride (CBN) and wurtzite nitrogen Boronide (WBN). Boron nitride crystal belongs to the hexagonal crystal system, its structure is similar to graphite, and its properties have many similarities, so it is also called “white graphite”.
Boron nitride ceramics have good heat resistance, thermal stability, thermal conductivity, high temperature dielectric Strength, is an ideal heat dissipation material and high temperature insulation material. Boron nitride is chemically stable and resistant to corrosion by most molten metals. It also has good self-lubricating properties. Boron nitride products have low hardness and can be machined with an accuracy of 1/100mm.
Boron nitride can be used to manufacture crucibles for smelting semiconductors and high-temperature containers for metallurgy, semiconductor heat-dissipating insulation parts, high-temperature bearings, thermowells and glass forming molds.The boron nitride usually obtained is a graphite-type structure, commonly known as white graphite.
The other is diamond type. Similar to the principle of converting graphite into diamond, graphite-type boron nitride can be converted into diamond-type boron nitride at high temperature (1800°C) and high pressure (800Mpa). The B-N bond length (156pm) in this boron nitride is similar to the C-C bond length (154pm) of diamond, and its density is similar to that of diamond. Its hardness is comparable to that of diamond, and its heat resistance is better than that of diamond. It is a new type of high temperature resistant superhard material for making drills, abrasives and cutting tools.
Precision Boron Nitride Ceramic Parts Manufacturer In China
Boron Nitride Ceramic can be processed via different fabrication techniques, including CNC machining, laser cutting, and injection molding. Boron Nitride Ceramic CNC machining at Pintejin offers a lot of unique advantages, we can manufacture ceramic parts with a high level of accuracy and low cost, whether you need high-quality CNC boron nitride ceramic parts or prototypes in a reliable and safe way. CNC machining ceramic parts are versatile and durable, however, this material is highly fragile and tends to fail when subjected to tensile and compressive forces. Based on years of experience, Pintejin is able to carry out cautious machining operations and avoid failure during the manufacturing, so as to reduce material waste then improve efficiency.Industry ceramic CNC machining will greatly raise the speed of boron nitride ceramic parts fabrication while maintaining correctness. Our skilled engineers and designers will fit your needs accordingly. Painting, polishing, and more surface finishing options are offered if you have cosmetic requirements.
Boron Nitride Ceramic CNC Machining Services – Boron Nitride Ceramic Machined Parts and Components Manufacturer
Boron Nitride Ceramic machining parts and molded parts are widely employed in various industries. Boron Nitride Ceramic parts has the advantages of lightweight, low price and easy machining. It is widely used in instrument parts, automobile lamps, optical lenses, transparent pipes, etc.
The Development History Of Boron Nitride
- Boron nitride came out more than 100 years ago. The earliest application was hexagonal boron nitride as a high-temperature lubricant. Not only its structure but also its properties are very similar to graphite, and it is white, so it is commonly known as white graphite.
- Boron nitride (BN) ceramics are compounds discovered as early as 1842. A lot of research work on BN materials has been carried out abroad since the Second World War, and it was not developed until the BN hot pressing method was solved in 1955. American Diamond Company and United Carbon Company first put into production, and in 1960, more than 10 tons were produced.
- In 1957, R·H·Wentrof took the lead in successfully trial-producing CBN. In 1969, General Electric Company of the United States sold it as a commodity Borazon. In 1973, the United States announced that it was made into CBN cutting tools.
- In 1975, Japan introduced technology from the United States and also prepared CBN tools.
- In 1979, the first successful use of pulsed plasma technology to prepare avalanche c-BN thin films at low temperature and low pressure.
- In the late 1990s, c-BN thin films were prepared by a variety of physical vapor deposition (PVD) and chemical vapor deposition (CVD) methods.
- From the perspective of China, the development is advancing by leaps and bounds. The research on BN powder began in 1963, and it was successfully developed in 1966. It was put into production in 1967 and applied to my country’s industry and cutting-edge technology.
The Physical And Chemical Properties Of Boron Nitride
The Material Properties Of Boron Nitride
CBN is usually black, brown or dark red crystals with a sphalerite structure and good thermal conductivity. The hardness is second only to diamond, and it is a superhard material that is often used as tool material and abrasive.
Boron nitride is chemically resistant and not attacked by inorganic acids and water. The boron-nitrogen bond is broken in hot concentrated alkali. Above 1200℃, it begins to oxidize in air. The melting point is 3000°C, and sublimation begins when it is slightly lower than 3000°C. Decomposition begins at about 2700°C under vacuum. Slightly soluble in hot acid, insoluble in cold water, relative density 2.25. The compressive strength is 170MPa. The maximum operating temperature is 900 °C in an oxidizing atmosphere, and can reach 2800 °C in an inactive reducing atmosphere, but the lubricating performance is poor at room temperature. Most of the properties of boron carbide are better than carbon materials. For hexagonal boron nitride: low coefficient of friction, good high temperature stability, good thermal shock resistance, high strength, high thermal conductivity, low coefficient of expansion, high electrical resistivity, corrosion resistance, microwave or Infrared transparent.
The Material Structure Of Boron Nitride
Boron nitride is a hexagonal crystal, most commonly a graphite lattice, and there are also amorphous variants. In addition to the hexagonal crystal form, boron carbide has other crystal forms, including: rhombohedral boron nitride (abbreviation: r-BN, or Said: trigonal boron nitride, its structure is similar to h-BN, which will be produced in the process of h-BN conversion to c-BN), cubic boron nitride [abbreviation: c-BN, or |3-BN, or z -BN (that is, sphalerite-type boron nitride), the texture is very hard], wurtzite-type boron nitride (abbreviation: w-BN, h-BN is a hard state under high pressure). Graphene-like 2D boron nitride crystals have even been found (similar to MoS: 2D crystals).
The Application Of Boron Nitride
- Release agent for metal forming and lubricant for metal wire drawing.
- Special electrolytic and resistance materials in high temperature state.
- High-temperature solid lubricants, extrusion anti-wear additives, additives for the production of ceramic composite materials, refractory materials and anti-oxidation additives, especially in the case of anti-corrosion of molten metals, heat-enhancing additives, high-temperature-resistant insulating materials.
- Heat-sealing desiccant for transistors and additives for polymers such as plastic resins.
- Pressed into various shapes of boron nitride products, can be used as high temperature, high pressure, insulation, heat dissipation parts.
- Heat shielding materials in aerospace.
- With the participation of catalyst, it can be converted into cubic boron nitride as hard as diamond after high temperature and high pressure treatment.
- Structural materials for atomic reactors.
- The nozzles of aircraft and rocket engines.
- Insulators for high-voltage high-frequency electricity and plasma arcs.
- Packaging materials to prevent neutron radiation.
- The superhard material processed by boron nitride can be made into high-speed cutting tools and drill bits for geological exploration and oil drilling.
- Metallurgically used for the separation ring of continuous casting steel, the runner of amorphous iron, the mold release agent for continuous aluminum casting (various optical glass release agents).
- Make various evaporation boats for capacitor film aluminum plating, picture tube aluminum plating, display aluminum plating, etc.
- All kinds of fresh-keeping aluminized packaging bags, etc.
- All kinds of laser anti-counterfeiting aluminum plating, trademark bronzing materials, all kinds of cigarette labels, beer labels, packaging boxes, cigarette packaging boxes aluminized and so on.
- Cosmetics are used as fillers for lipsticks, which are non-toxic, lubricious and glossy.
Due to the high hardness of steel materials, a lot of heat will be generated during machining. Diamond tools are easy to decompose at high temperatures and are easy to react with transition metals, while c-BN materials have good thermal stability and are not easy to occur with iron group metals or alloys. It can be widely used in precision machining and grinding of steel products. In addition to excellent wear resistance, c-BN also has excellent heat resistance. It can also cut heat-resistant steel, ferroalloy, quenched steel, etc. at a relatively high cutting temperature, and can cut high-hardness chilled rolls, seepage Carbon quenching materials and Si-Al alloys, which are very serious for tool wear. In fact, tools and abrasives made of sintered bodies of c-BN crystals (synthesized at high temperature and high pressure) have been used in high-speed precision machining of various cemented carbide materials.
As a wide-gap (6.4 eV) semiconductor material, c-BN has high thermal conductivity, high resistivity, high mobility, low dielectric constant, high breakdown electric field, can achieve dual-type doping, and has good It is called the third-generation semiconductor material after Si, Ge and GaAs together with diamond, SiC and GaN. Their common feature is a wide band gap, which is suitable for making electronic devices used under extreme conditions. Compared with SiC and GaN, c-BN has superior properties with diamond, such as wider band gap, higher mobility, higher breakdown electric field, lower dielectric constant and higher thermal Conductivity. Obviously, as an extreme electronic material, c-BN is better than diamond. However, as a semiconductor material, diamond has its fatal weakness, that is, the n-type doping of diamond is very difficult (the resistivity of n-type doping can only reach 102 Ω·cm, which is far from the device standard), while c-BN is Dual-type doping can be achieved. For example, in the process of high temperature and high pressure synthesis and thin film preparation, adding Be can obtain a p-type semiconductor; adding S, C, Si, etc. can obtain an n-type semiconductor. Therefore, it seems that c-BN is the third-generation semiconductor material with the most excellent performance. It can not only be used to prepare electronic devices that work under extreme conditions such as high temperature, high frequency, and high power, but also has excellent performance in deep ultraviolet light emitting and detectors. Broad application prospects. In fact, c-BN light-emitting diodes made under high temperature and high pressure conditions were first reported, which can work at a temperature of 650 °C. Under forward bias, the diode emits blue light visible to the naked eye. Spectral measurements show that its shortest wavelength is 215 nm (5.8 eV). c-BN has a thermal expansion coefficient similar to GaAs and Si, high thermal conductivity and low dielectric constant, good insulation performance and good chemical stability, making it a heat sink material and insulating coating for integrated circuits. In addition, c-BN has a negative electron affinity and can be used as a cold cathode field emission material, which has broad application prospects in the field of large-area flat-panel displays.
In optical applications, c-BN film is suitable for surface coating of some optical components due to its high hardness and high transmittance from ultraviolet (starting from about 200 nm) to far infrared. Coating of window materials such as zinc selenide (ZnSe) and zinc sulfide (ZnS). In addition, it has good thermal shock resistance and quotient hardness, and is expected to be an ideal window material for high-power lasers and detectors.