We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Technology

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Is Cubic Boron Nitride?

By E.A. Sanker
Updated: May 17, 2024
Views: 10,886
Share

Cubic boron nitride (CBN) is a synthetic chemical compound made up of boron and nitrogen atoms in a one-to-one ratio. Unlike other types of boron nitride, it exists as a cubic crystal lattice, with its atoms arranged in a symmetrical, cube-shaped structure like the crystalline structure of diamond. Its material properties include extreme hardness, stability under heat, and superior chemical resistance. Cubic boron nitride is the second-hardest known material after diamond, making it useful in a wide variety of industrial applications, where it is often used as an abrasive or cutting tool.

All boron nitride compounds are produced synthetically, since they are not found in nature. The process starts with boric acid, a compound of boron, oxygen, and hydrogen, or with boron trioxide, which is made up of boron and oxygen. Either of these compounds can be reacted with urea or ammonia, which contain nitrogen, to produce a powder of boron nitride. The powder is crystallized through intense heat to form hexagonal boron nitride, which has a hexagonal crystal structure analogous to that of graphite, a precursor of synthetic diamond. Hexagonal boron nitride is then heat-treated under high pressure to form cubic boron nitride.

CBN has several advantages as an industrial material. It is almost as hard as diamond, making it useful for cutting and abrasion of metals and other substances. The heat resistance of CBN is also quite high. Diamond begins to decompose to carbon dioxide in air at around 1,472°F (about 800°C), whereas cubic boron nitride is stable in air up to about 2,552°F (about 1,400°C). In industrial grinding applications and other processes where intense heat is generated, CBN is preferred over diamond.

Another advantage of CBN as an alternative to diamond is its chemical stability in the presence of nickel, iron, and related substances. Diamond is soluble in these metals, meaning that it reacts with them chemically and dissolves. This makes it useless as a tool for cutting iron or steel. CBN, on the other hand, does not react and can therefore be used to cut these materials.

The variety of CBN used in industrial cutting tools is known as polycrystalline cubic boron nitride (PCBN). PCBN is manufactured by sintering cubic boron nitride particles with ceramics. In sintering, the boron nitride is placed in a furnace under high heat and pressure that binds it with the ceramic, fusing into the extremely hard substance used for grinding and cutting.

Share
WiseGeek is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Editors' Picks

Discussion Comments
Share
https://www.wisegeek.net/what-is-cubic-boron-nitride.htm
Copy this link
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.