About Boron Nitride(BN) Ceramics

Boron nitride crystal belongs to the hexagonal system, the structure is similar to graphite, and there are many similarities in performance, so it is also called “white graphite”.

It has good heat resistance, thermal stability, thermal conductivity, high-temperature dielectric strength, and is an ideal heat dissipation material and high-temperature insulating material. Boron nitride has good chemical stability and can resist most of the erosion of molten metal. It also has good self-lubricating properties. Boron nitride products have low hardness and can be machined with an accuracy of 1/100mm.

The composition of BN ceramics

BN 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 Boron (WBN).

Our Boron Nitride Ceramic Service

Great Ceramic is an expert in the production of technical ceramics. Since 2013, we have participated in and provided more than 3,000 types of precision ceramic products to hundreds of companies.
We can provide you with ceramic processing, ceramic raw materials, ceramic mold forming, surface metallization and other services, and we are committed to providing only products and services that meet or exceed customer quality requirements.

 

Machining

Materials

Available Grades of BN Ceramics

  1. Pyrolytic Boron Nitride(PBN):Purity is greater than 99.99%
  2. Hexagonal Boron Nitride(HBN): BN(>99%)+ Boric Oxide(B2O3)
  3. Composite Boron Nitride Ceramics:
    • CABN: BN + Calcium Borate
    • ALBN: BN + Al2BO3
    • ZRBN: BN + Zirconium Oxide + Boric Oxide(B2O3)
    • ZABN: BN + Zirconium Oxide + Aluminum Nitride + Al2BO3
    • SCBN: BN + Silicon Carbon + Al2BO3

Boron Nitride Ceramic Display:

Pyrolytic Boron Nitride (PBN) belongs to the hexagonal crystal system, with a purity of 99.999%, acid and alkali resistance, oxidation resistance, good thermal conductivity, compactness, and processing. It is formed by chemical vapor deposition (CVD) of ammonia and boron halides under high temperature and high vacuum conditions. It can be used to prepare PBN plates, or directly prepare crucibles, boats, coatings and other PBN final products.

Pyrolytic boron nitride is different from ordinary hot-pressed boron nitride (HBN). It does not need to go through the traditional hot-pressed sintering process and does not add any sintering agent. Therefore, the obtained product has the following remarkable characteristics:

  1. Non-toxic and tasteless;
  2.  High purity, reaching more than 99.999%;
  3. It does not react with acids, alkalis, salts and organic reagents at room temperature. It is slightly corroded in molten salt and lye, but it can resist the corrosion of various acids at high temperatures;
  4. Does not react with most molten metals, semiconductors and their compounds;
  5. Under 1000℃, good anti-oxidation performance;
  6. Good thermal shock resistance, no cracks were found when dropped into water at 2000℃;
  7. The use temperature is high, there is no sublimation point, and it can be directly decomposed into B and N above 3000℃;
  8. High resistance and good electrical insulation performance;
  9. The surface is smooth, without pores, and is not wet with most semiconductor melts.

Due to the nature of the CVD process, pyrolytic boron nitride parts usually require a wall thickness of no more than 3 mm. However, the CVD process makes the pyrolytic boron nitride have a nearly perfect layered structure, resulting in anisotropic thermal conductivity, making it an ideal material for making crystal growth crucibles.

Pyrolytic Boron Nitride Ceramic Products

Applications:

1. OLED evaporation unit;

2. Semiconductor single crystal growth (VGF, LEC) crucible;

3. Molecular beam epitaxy (MBE) evaporation crucible;

4. MOCVD heater;

5. Polycrystalline synthesis boat;

6. PBN infrared window;

7. Satellite communication microwave tube;

8. PBN coated carrier plate;

9. Insulation board for high temperature and high vacuum equipment.

Boron nitride ceramic materials have excellent machining properties and can be processed into complex shapes with very small tolerances as required.
The following matters should be paid attention to in the processing of boron nitride ceramic materials:
1. All boron nitride ceramic materials can be processed with standard high-speed steel cutting tools. For the processing of composite materials with harder materials, cemented carbide tools or diamond tools are recommended.
2. Grinding can be carried out as required, and standard taps and dies can be used to machine threads.
3. The machining process should always be kept dry, without the use of cutting oil and coolant.
4. Cutting tools should be sharp and clean. Do not use cutting tools with negative inclination.
5. When processing materials, be careful when jamming and clamping to avoid excessive pressure. Down-milling technology should be used to prevent missing edges and corners.

 

The Advantages Of Hexagonal BN Ceramics:

  • High heat resistance: sublimation at 3000°C; at 1800°C, its strength is twice that at room temperature. It will not break when cooled from 1500°C to room temperature dozens of times; it will not become soft in an inert gas at 2800°C.

  • High conductivity: The hot-pressed product is 33W/MK, the same as pure iron. When it is higher than 530℃, it has the maximum thermal conductivity above 530℃.

  • Low thermal expansion coefficient: Its thermal expansion coefficient is 2×10-6, second only to quartz glass, and the lowest among ceramics. Due to its high thermal conductivity, it has high thermal shock resistance.

  • Excellent electrical properties: excellent high-temperature insulation; up to 1014Ω-cm at 25°C and 103Ω-cm at 2000°C. So it is the best high temperature. Insulating material in ceramics. When the breakdown voltage is 3KV/MV, the low dielectric loss is 108HZ, it can reach 2.5×10-4, the dielectric constant is 4, and it can penetrate microwave and infrared rays.

  • Extremely strong corrosion resistance: Will not react with common metals (iron, copper, aluminum, lead, etc.), rare earth metals, precious metals, semiconductor materials (germanium, silicon, potassium arsenide), glass, molten salt (crystal) , Fluoride and slag), inorganic acids and alkalis.

  • Low friction coefficient: U is 0.16, which will not increase at high temperature. It has higher temperature resistance than molybdenum disulfide and graphite. The oxidizing atmosphere is 900°C; it can be used at 2000°C under vacuum.

  • High purity and high boron content: the impurity content is less than 10PPM, and the boron content exceeds 43.6%.

  • Machinability: Its hardness is Mohs 2, so it can be processed into high-precision parts and components by conventional machining.

Mechanical Properties

PropertiesUnitHBNPBNComposite BN
Main Ingredients%BN>99%BN>99.99%Many kinds
Adhesive——B2O3NoMultiple types
Colour——WhiteWhiteGrey
Densityg/cm³2.02.0~2.22.3~2.9
Hardness(Knoop)MPa39692>100
Compressive StrengthMPa100173280
Flexural StrengthMPa30150>100

Thermal Properties

PropertiesUnitHBNPBNComposite BN
Maximum Use Temperature℃ (in oxidizing atmosphere)85010001000
Maximum Use Temperature℃ (in an inert atmosphere)220030002000
Maximum Use Temperature℃ (under vacuum environment)18002300——
Thermal Conductivity @ 25°CW/(M・K)>306035
Thermal Expansion at 25–1000°C 10-6/℃>1.8——2
Specific Heat J/g·℃0.810.90——

Electrical Properties

PropertiesUnitHBNPBNComposite BN
Dielectric Constant1MHz4.03.0——
Dielectric StrengthkV/mm79569.0
Volume Resistivity @ 25°CΩ・cm>1013>1014>1013

*The values are typical material properties and may vary according to products configuration and manufacturing process. For more details, Please feel free to contact us.

 

What can Boron Nitride Ceramics be used for?

  • Fracture ring for continuous casting of metal
  • Heat treatment fixture
  • High temperature lubricant
  • Release agent
  • Molten metal and glass castings
  • Nozzle for transfer or atomization
  • Laser nozzle
  • Ion thruster discharge channel
  • Nuclear shield
  • Induction heating coil bracket
  • Gasket
  • High temperature and high voltage electric insulator
  • Furnace support requiring resistivity
  • Crucible and container for high purity molten metal
  • Radar components and antenna windows

Boron Nitride Machining & Sales

Great Ceramic is your boron nitride machining specialist for your precision 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 BN ceramics plates, rods, tubes or custom machined components, please contact us and one of our experts will be happy to assist you.