Boron Nitride (BN)

Boron Nitride is an advanced synthetic ceramic material available in solid and powder form. Its unique properties – from high heat capacity and outstanding thermal conductivity to easy machinability, lubricity, low dielectric constant and superior dielectric strength – make boron nitride a truly outstanding material.

In its solid form, boron nitride is often referred to as “white graphite” because it has a microstructure similar to that of graphite. However, unlike graphite, boron nitride is an excellent electrical insulator that has a higher oxidation temperature. It offers high thermal conductivity and good thermal shock resistance and can be easily machined to close tolerances in virtually any shape. After machining, it is ready for use without additional heat treating or firing operations.

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Milling of Boron Nitride Video

Milling of Boron Nitride Grade HP Ceramic into finished component with Robodrill Machining Centre fitted with probe system.

Boron Nitride Properties

To make solid shapes, hBN powders and binders are hot-pressed in billets up to 490mm x 490mm x 410mm at pressures up to 2000 psi and temperatures up to 2000°C. This process forms a material that is dense and easily machined and ready to use. It is available in virtually any custom shape that can be machined and has unique characteristics and physical properties which make it valuable for solving tough problems in a wide range of industrial applications.

  • Excellent thermal shock resistance
  • High electrical resistivity – excluding aerosols, paints, and ZSBN
  • Low density
  • High thermal conductivity
  • Anisotropic (thermal conductance is different in different planes relative to pressing direction)
  • Corrosion resistant
  • Good chemical inertness
  • High temperature material
  • Non-wetting
  • High dielectric breakdown strength, >40 KV/mm
  • Low dielectric constant, k=4
  • Excellent machinability

Material Grades

PCBN1000

General Properties

PCBN1000 is a hot-pressed boron nitride, engineered to work in the most demanding applications. This high purity material is designed to exhibit low thermal expansion while having superb thermal shock properties.

PCBN1000 is easily machinable, has an excellent thermal conductance, very low thermal cycling behaviour in use and has good chemical resistivity to molten metal and glass. The lubricity of the material enables low frictional values even at elevated temperatures.

PCBN1000 is also an electrical insulator with outstanding properties, high dielectric strength and electrical resistivity. The properties of

PCBN1000 are ideal for high temperature applications where the only alternative is using a boron nitride with no binder. It can be made up to 300mm in diameter and 300mm in length.

Applications

  • Setter plates for high temperature furnaces
  • Crucibles for molten glass and metals
  • Electrical insulators for high temperatures and high voltages
  • Vacuum feedthroughs
  • Plasma chamber lining and fittings
  • Nozzles for non-ferrous metals and alloys
  • Thermocouple protection tubes and sheaths
  • Laser supports

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PCBN2000

General Properties

Hot pressed for strength, PCBN2000 is an advanced composite, a boron nitride/silica compound delivering excellent dielectric performance and insulation. This material has excellent thermal shock resistance while delivering low thermal expansion.

PCBN2000 is easily machined and has good flexural strength for a boron nitride.

Applications

  • Aerospace for electric propulsion discharge channels/Hall effect thrusters
  • Plasma/corona insulators
  • Plasma constraints in PVD systems
  • Wear and corrosion resistance
  • Ultra high vacuum insulators

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PCBN3000

General Properties

PCBN3000 is a unique hot-pressed boron nitride, engineered to work in the most demanding applications. This high purity material exhibits very low thermal expansion with superb thermal shock properties.

Binder-free PCBN3000 is the lowest hardness hexagonal Boron Nitride. It is easily machinable to very tight tolerances, has excellent thermal conductivity, very low thermal cycling behavior and good chemical resistivity to molten metals at very high temperatures. The lubricity of the material enables low frictional values. It is non-reactive with graphite and refractory metals in the 2000C range.

PCBN3000 is also an electrical insulator with outstanding properties, retaining high dielectric strength and electrical resistivity at extreme temperatures.

The properties of PCBN3000 are ideal for high temperature applications where the only option is boron nitride with no binder. It can be machined in large shapes from billets up to 490 x 490 x 400mm.

Applications

  • Setter plates for high temperature furnaces
  • Crucibles for non-oxide ceramics, phosphors, and metals
  • Electrical insulation for extremely high temperatures and high voltages
  • Components exposed to molten salts
  • Hall Effect Thruster insulators
  • Nozzles for non-ferrous metals and alloys
  • Thermocouple protection tubes and sheaths
  • Laser supports

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PCBN4000

General Properties

PCBN4000 is a unique hot-pressed boron nitride, engineered to work in the most demanding applications. This stronger, harder Boron Nitride grade exhibits low thermal expansion with superb thermal shock properties.

PCBN4000 is the economical workhorse grade of hexagonal Boron Nitride. It is easily machinable to very tight tolerances, has good thermal conductivity, very low thermal cycling behaviour and chemical resistivity to molten metals to over 1000C. The lubricity of the material enables low frictional values.

The properties of PCBN4000 are ideal for where the strength of the calcium borate glass binder is needed. It can be machined in large shapes from billets up to 490 x 490 x 400mm.

PCBN4000 is also an electrical insulator with outstanding properties, retaining high dielectric strength and electrical resistivity up to 1000C.

Applications

  • Setter plates for furnaces
  • Crucibles for non-oxide ceramics, phosphors, and metals
  • Electrical insulation for high temperatures and high voltages
  • Components exposed to molten salts • Hall Effect Thruster insulators
  • Nozzles for non-ferrous metals and alloys
  • Thermocouple protection tubes and sheaths

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PCBN5000

General Properties

PCBN5000 is a specific hot-pressed boron nitride, engineered to work in the most demanding applications. It is the combination of properties, along with its machinability, that makes this such a versatile and valuable grade.

This very unique grade of hexagonal Boron Nitride, PCBN5000, is essentially high purity BN crystals bonded in a silica matrix. This gives it a moisture resistance that other BN grades do not possess. It is easily machinable to very tight tolerances, and has a unique fracture toughness.

PCBN5000 fracture toughness derives from its ability to deflect/blunt crack propagation. In addition, similar to silica glasses, it can exceed its stated temperature range, for short periods of time. It won’t thermal shock. And if brought back down, its shape and properties will be maintained. It can be machined in very large shapes, from billets up to 490 x 490 x 400mm.

PCBN5000 is also an electrical insulator with outstanding dielectric and microwave properties, retaining high dielectric strength and electrical resistivity up to 1000C.

Applications

  • Microwave components
  • Electrical insulation for high temperatures and high voltages
  • Hall Effect Thruster insulators

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Grade A

General Properties

An excellent choice for all but the most severe refractory applications, Solid Boron Nitride Grade A is a high performance material possessing a glassy B2O3 binder that creates a hard and dense yet fully machinable product.

B2O3-bonded, A Grade is the oldest form of hot-pressed Boron Nitride. Specified into applications 50+ years ago, A Grade still finds a substantial replacement business as relatively high-temperature insulators in legacy semiconductor equipment and defense markets. Components up to 410mm x 495mm x 245mm can be produced. However, its B2O3 binder is hygroscopic and care must be taken to ensure components are isolated from moisture during storage and use. Precision Ceramics USA uses many methods of packaging to maintain the high quality of its machined components.

Applications

  • High temperature electrical insulators and vacuum furnace supports which require electrical resistivity, high temperature strength, thermal shock resistance and low chemical reactivity
  • Crucibles and containers for high purity molten metals
  • Insulators and source fixtures for ion implantation systems which require high temperature purity and electrical insulation
  • Radar components and antenna windows which require exacting electrical and thermal properties
  • Setterplates for the processing of other advanced materials which require stable, inert surfaces
  • Nozzles for powdered metal spraying

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Grade AX05

General Properties

Solid Boron Nitride Grade AX05 is one of the highest purity hexagonal boron nitride solids available and a wise choice for applications where corrosion resistance is more important than wear resistance. It is a diffusion bonded ceramic and does not depend on B2O3 to other binders for mechanical integrity and, consequently, it is non-wet by almost all molten metals. This ultra purity advantage allows for applications and uses not provided by other hot pressed boron nitride solids, such as crucibles for high-purity molten metals. Commonly used in applications that demand very high thermal conductivity such as nozzles with small orifices.

Key Properties

Chemically

Grade AX05 is extremely inert and non-wet by many molten materials such as metals, glasses, halide salts and other reagents. The chemical stability allows Grade AX05 to provide a stable, non-reactive material for nozzles, feed- throughs, crucibles and supports.

Thermally

Grade AX05 has minimal thermal expansion, high thermal conductivity and use temperature in certain inert atmospheres over 2000°C. Thermal shock stability is excellent over a wide range of use temperatures.

Mechanically

Grade AX05 yields increasing relative strength vs. temperature. This important feature provides higher temperature performance to applications previously unattainable with B2O3 to other bonded boron nitrides.

Electrically

Grade AX05 is transparent to microwave energy. It also provides high resistivity and dielectric strength with a low loss tangent and dielectric constant. These characteristics make AX05 an excellent material for high power, low loss insulators, containers and fixtures.

Machinability

Grade AX05 can be machined to extremely close tolerances using standard high speed “tool steel” equipment. Machining by grinding may be used if preferred or stringent tolerances are required. Threads can be machined using taps and dies. Cutting oils and coolants should not be used for any reason.

Applications

  • High temperature electrical insulators and vacuum furnace supports which require electrical resistivity, high temperature strength, thermal shock resistance and low chemical reactivity.
  • Crucibles and containers for high purity molten metals Insulators and source fixtures for ion implantation systems which require high temperature purity and electrical insulation.
  • Setter plates for the processing of other advanced materials which require stable, inert surfaces.
  • Nozzles for powdered metal spraying.

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Grade HP

General Properties

HP Boron Nitride is the workhorse grade of BN, useful when low thermal expansion, high thermal shock resistance, and strong electrical properties are required. To minimize the moisture issues of A Grade, HP was developed with a calcium borate glass binder. It is available in shapes up to 410mm x495mm x 245mm. With its excellent machinability and good to over 1000°C in inert or vacuum, it finds many diverse applications.

When higher thermal shock, more spall resistance and lower permanent expansion upon heating is required, Solid Boron Nitride Grade HP is a superior solid grade for formulations of <1,000°C. Additionally, Grade HP has ten times the moisture resistance of Grade A due to the addition of calcium which combines with boric oxide to form calcium borate. Commonly used for many light metal applications such as Al, Ti, Mg and Zn.

Key Properties

Chemically

High corrosion resistance due to the addition of boron nitride; ten times the moisture resistance of other boron nitride solids due to the addition of calcium which combines with boric oxide to form calcium borate.

Thermally

Excellent thermal shock resistance and conductivity – commonly used in many light metal applications such as Al, Ti, Mg, and Zn.

Electrically

Low dielectric constant material – also commonly used in many high temperature insulators.

Machinability

Like other grades of Boron Nitride, Grade HP can be machined using standard high speed ‘tool steel’ equipment. Machining by grinding may be used if preferred or stringent tolerances are required.

Applications

  • High temperature electrical insulators and vacuum furnace supports which require electrical resistivity, high temperature strength, thermal shock resistance and low chemical reactivity
  • Crucibles and containers for high purity molten metalsInsulators and source fixtures for ion implantation systems which require high temperature purity and electrical insulation
  • Radar components and antenna windows which require exacting electrical and thermal properties
  • Setter plates for the processing of other advanced materials which require stable, inert surfaces
  • Nozzles for powdered metal spraying

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Grade HPL

General Properties

Designed by Saint-Gobain for a specific semiconductor equipment OEM, HPL has many of the properties of HP Grade, except a somewhat increased temperature range. It is primarily marketed in Asia, but with growing application in the US. It is softer than HP Grade due to its lower binder content and still very machinable to complex shapes and tight tolerances.

Grade M26/M

General Properties

Solid Boron Nitride Grade M is a truly hydrophobic advanced ceramic. Composed of boron nitride and silica, it is completely resistant to moisture and has a MIL-I-10A grade of L542, a test requiring immersion in water for 48 hours prior to testing at elevated frequencies. Grade M is suitable for the most severe electrical applications. It is an excellent refractory material at temperatures up to 1400°C, and is unparalleled in resistance to thermal shock.

Solid Boron Nitride Grade M26 is a truly hydrophobic advanced ceramic. Composed of boron nitride and silica, it is completely resistant to moisture and has a MIL-I-10A grade of L542, a test requiring immersion in water for 48 hours prior to testing at elevated frequencies. Grade M26 is suitable for the most severe electrical applications. It is an excellent refractory material at temperatures up to 1400°C, and is unparalleled in resistance to thermal shock.

Applications

  • High temperature electrical insulators and vacuum furnace supports which require electrical resistivity, high temperature strength, thermal shock resistance and low chemical resistivity
  • Crucibles and containers for high purity molten metals
  • Tools and refractories for glass forming which provide non-wetting, non-B2O3 containing contacts
  • Radar components and antenna windows which require exacting electrical and thermal properties

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Grade ZSBN

General Properties

Developed for demanding applications requiring the combination of thermal conductivity, high wear resistance and boron nitrides corrosion resistance, Grade ZSBN boron nitride is a composite material combining the best thermal performance and machinability characteristics of hot-pressed boron nitride with the strength and non-reactivity of silicon carbide and zirconia.

ZSBN is unique because it is a composite material that combines the best properties of hot-pressed boron nitride with the non-reactivity and strength/wear resistance of zirconia. Originally developed for break rings for horizontal continuous casters, its unique thermal, chemical, electrical, wear, and machinability properties permit a wide variety of molten-metal-contact applications. hBN is an inherently soft material. However, with ZSBN’s hard ZrO2 particles evenly dispersed with BN platelets in the hard borosilicate glass matrix, it has great wear properties added to the inherent non-wetting aspects of the hBN.

ZSBN is a uniquely high-performing solid that is especially suited for molten metal applications such as continuous casting break rings, where wear resistance and thermal conductivity are essential. There are many applications in molten-metal atomizing nozzles, glass contact wear components, and countless guides and rollers in diverse light-metal baths of Zn, Mg and Al. And increasingly, lithium, as battery development continues.

Key Properties

Chemically

Unparalleled resistance to molten metal wetting due to boron nitride content.

Thermally

Excellent high temperature operation and thermal shock resistance.

Mechanically

Excellent wear resistance and increased strength from zirconia and a small amount of silicon carbide. This feature, unique to ZSBN, results in remarkable corrosion resistance over a wide range of temperatures.

Machinability

Grade ZSBN is easily machined, even to complex shapes and forms, quickly and inexpensively. Machining tolerances of 0.002” or better are achievable.

Applications

  • Break rings
  • Components
  • Continuous casting
  • Crucibles
  • Deck plates
  • Heat treatment fixtures
  • High temperature bearings
  • High temperature mechanical components
  • High temperature valves
  • Jigs
  • Moulds
  • Motel metals and glass casting
  • Muffles
  • Nozzles for transfer or atomization
  • Side dams
  • Spacer

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Related Materials

Boron Nitride is one of the few materials that offers electrical insulation and high thermal conductivity. This makes BN extremely useful in high power electronic applications in heat sink and heat spreader applications. Other materials that are commonly used are Aluminum Nitride, beryllium oxide, and sometimes Alumina – however, all of these materials are significantly more difficult to machine into intricate shapes.

Boron Carbide

Boron Carbide

Boron Carbide (B4C), also known as black diamond, is the third hardest material after diamond and cubic boron nitride. It is a suitable material for many high performance applications due to its attractive combination of properties.

Ceramic Material - CeramAlum (Aluminum Nitride)

Aluminum Nitride

Aluminum Nitride (AlN) is an excellent material to use if high thermal conductivity and electrical insulation properties are required -- an ideal material for use in thermal management and electrical applications.

Ceramic Material - CeramAlox (Alumina / Aluminum Oxide)

Alumina / Aluminum Oxide

Alumina, also known as Aluminum Oxide, is a hard wearing advanced technical ceramic material frequently used in a wide variety of industrial applications.

Boron Nitride Machining

Hexagonal boron nitride can be machined into highly complex geometries with very tight tolerances. Precision Ceramics has 3, 4 and 5 axis CNC machining capabilities and over 20 years of experience creating custom boron nitride components.

Precision Ceramics is your Boron Nitride machining specialist for your technical ceramic prototyping & manufacturing needs; we are always happy to use our many years of advanced ceramics experience to provide advice on materials, design, and application. If you would like to buy Boron Nitride plates, bars, rods, tubes, Aerosol Sprays, Paintable Coatings, Industrial Powders, or custom machined parts, please contact us and one of our experts will be happy to assist you.

Frequently Asked Questions

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    What is Boron Nitride used for?

    Boron Nitride is available in virtually any custom shape that can be machined and has unique characteristics and physical properties which make it valuable for solving tough problems in a wide range of industrial applications.

    • Break rings for continuous casting of metals
    • Continuous casting
    • Crucibles and containers for high purity molten metals
    • Deck plates
    • Heat treatment fixtures
    • High temperature lubricant
    • High temperature valves
    • High temperature & high voltage electrical insulatorsInduction heating coil supports
    • Laser Nozzles
    • Molds/mold release agent
    • Motel metals and glass casting
    • Nozzles for transfer or atomization
    • Nuclear Shielding
    • Radar components and antenna windows
    • Refractory applications
    • Spacers
    • Vacuum furnace supports which require electrical resistivity
  • image/svg+xmlimage/svg+xml
    What is Boron Nitride?

    Boron Nitride (BN) is an advanced synthetic ceramic material available in solid and powder form. Its unique properties – from high heat capacity and outstanding thermal conductivity to easy machinability, lubricity, low dielectric constant and superior dielectric strength – make boron nitride a truly outstanding material.

    In its solid form, boron nitride is often referred to as “white graphite” because it has a microstructure similar to that of graphite. However, unlike graphite, boron nitride is an excellent electrical insulator that has a higher oxidation temperature. It offers high thermal conductivity and good thermal shock resistance and can be easily machined to close tolerances in virtually any shape. After machining, it is ready for use without additional heat treating or firing operations.

    In inert and reducing atmospheres, the AX05 grade of Boron Nitride grades will withstand temperatures over 2,000°C.   It is commonly used as an insulator in contact with tungsten and graphite electrodes at those temperatures.