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Cubic Boron Nitride (CBN)

Cubic Boron Nitride (cBN), belonging to the boron nitride material family, is second only to diamond in hardness and is particularly favored for its use in abrasive and cutting tool applications due to its unique combination of high abrasion resistance, superior thermal conductivity, and remarkable chemical stability at elevated temperatures. This synthetic crystalline material distinguishes itself from diamond by its ability to retain structural integrity and resist graphitization at temperatures up to 1400°C, making it more suitable for processing ferrous materials. Its chemical inertness, especially towards iron and steel at high temperatures, positions cBN as an indispensable material for high-temperature machining and grinding operations, where it outperforms traditional abrasives.

CBN's exceptional properties, including its thermal stability and high thermal conductivity, are crucial for efficient heat management during intensive industrial tasks, enhancing tool longevity and performance. As a standout member of the boron nitride family, cBN's wear resistance and ability to maintain hardness under thermal stress make it a preferred choice for the development of durable, high-performance industrial tools and components. These attributes ensure cBN's pivotal role in applications demanding maximum durability, effective thermal management, and chemical resistance, solidifying its status as a critical material in advanced manufacturing processes.

More Info About Cubic Boron Nitride

Products | Structure | Specification | Applications | Video | FAQs 


Cubic Boron Nitride Structure

Cubic Boron Nitride (cBN) possesses a crystalline structure that closely resembles that of diamond, making it one of the hardest materials known. This structure is characterized by a cubic lattice in which boron and nitrogen atoms are alternately situated, similar to the carbon atoms in diamond. This arrangement allows for the strong covalent bonding between boron and nitrogen atoms, providing cBN with its exceptional hardness and thermal stability.

The cubic structure of cBN is responsible for its high resistance to wear and thermal shock, making it ideal for cutting and abrasive applications, especially in environments where materials are subjected to high temperatures and pressures. Unlike diamond, cBN does not convert to graphite under high temperatures, maintaining its integrity and properties up to about 1400°C in air. This stability, combined with its chemical inertness, especially to ferrous materials, makes cBN an invaluable material in industrial processes involving high-speed machining, grinding of hard materials, and applications demanding high durability and resistance to thermal and chemical degradation.

Read more: Hexagonal Boron Nitride VS. Cubic Boron Nitride

Cubic Boron Nitride Specification

Physical Properties
Chemical Formula BN
Density (g/cm3) 3.48
Color Typically transparent to pale yellow
Crystal Structure Cubic
Mechanical Properties
Hardness (Vickers) 4500 kg/mm²
Compressive Strength MPa @ R.T. 3,800
Modulus of Elasticity (Young's Mod.) Gpa 700-800
Electrical Properties
Dielectric Constant 1MHz @ R.T. ~7.0 (varies by purity)
Electrical Resistivity Wcm @ R.T. >10^16
Thermal Properties
Thermal Conductivity W/m-K @ R.T. 200-700 (highly dependent on orientation and purity)

Cubic Boron Nitride Applications

Cubic Boron Nitride (cBN) is a superabrasive material with a wide range of industrial applications due to its exceptional hardness, thermal conductivity, and chemical stability. Below are key applications of cBN:

Cutting and Machining Tools

Hardened Steels: cBN is extensively used for machining hardened steels, offering high resistance to wear and maintaining sharpness longer than conventional tools.

High-temperature Alloys: It's ideal for cutting nickel-based and cobalt-based superalloys, commonly used in aerospace and energy industries, due to its thermal stability.


Grinding Wheels: cBN grinding wheels are preferred for their ability to grind tough materials with precision and minimal heat generation.

Polishing Tools: In precision polishing, cBN is used for its uniform abrasion, ensuring high-quality surface finishes on metals and alloys.


Heat Sinks and Substrates: The high thermal conductivity of cBN makes it suitable for heat sinks and substrates in electronic devices, effectively dissipating heat and improving device performance.

Wear Parts

Bearings and Seals: cBN's hardness and wear resistance make it a material of choice for bearings and seals in machinery exposed to high stress and abrasive conditions.

Aerospace and Defense

Protective Coatings: cBN coatings protect components against wear and thermal degradation in harsh environments, such as in jet engines and missile systems.


Brake Discs and Engine Components: The high thermal conductivity and wear resistance of cBN contribute to the manufacturing of durable brake discs and engine components that withstand high temperatures and stress.

ACM Ceramic Product Video

Your CBN Ceramics Supplier

Advanced Ceramic Materials is a leading supplier of cubic boron nitride ceramic products of the highest quality for a wide range of applications. We are happy to provide advice on materials, design, and application. Feel free to contact us with any questions about CBN or other ceramic materials that are not listed on the website. 

How Is cBN Different from Diamond?
While both cBN and diamond are extremely hard materials, cBN is better suited for machining ferrous materials because it does not react with iron at high temperatures, unlike diamond. cBN also retains its hardness at higher temperatures than diamond.
Can cBN Be Used at High Temperatures?
Yes, cBN maintains its hardness and stability at temperatures up to about 1400°C in air, making it suitable for high-temperature applications where materials like diamond would degrade.
How is cBN synthesized?
Cubic boron nitride is synthesized through high-pressure, high-temperature processes that mimic the conditions under which natural diamonds are formed. This involves subjecting hexagonal boron nitride (hBN) to extreme pressures and temperatures in the presence of a catalyst.
What Makes cBN Suitable for Abrasive Applications?
Its extreme hardness, second only to diamond, along with its thermal and chemical stability, makes cBN an excellent material for abrasive and cutting tools, providing high performance in machining hard materials.
How Does cBN Perform in Comparison to Other Abrasive Materials?
cBN offers superior performance when machining hard ferrous materials, outlasting other abrasives like silicon carbide or alumina in terms of wear resistance, thermal stability, and overall efficiency in cutting operations.
Are There Different Grades Of cBN?
Yes, cBN is available in various grades, each tailored for specific applications. These grades differ in terms of purity, grain size, and bonding materials, affecting their performance in different machining and grinding tasks.
How Is Cubic Boron Nitride Applied to Cutting Tools?
cBN can be sintered into solid tools, coated onto substrates, or used as an abrasive grit in grinding wheels and other tools. The choice of application method depends on the specific requirements of the machining process and the material being worked on.
Can CBN Be Reused or Recycled?
Yes, cBN grinding wheels and tools can often be reconditioned or recycled, extending their life and reducing waste. The recycling process involves re-machining the used tool to reveal new abrasive layers.
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