Editing Boron nitride (section)

===Cubic BN===
Cubic boron nitride (CBN or c-BN) is widely used as an [[abrasive]].<ref name="mprg">{{Cite book | vauthors = Todd RH, Allen DK, Dell KAlting L | year = 1994 | title = Manufacturing Processes Reference Guide | publisher = Industrial Press Inc. | pages = 43–48 | url = https://books.google.com/books?id=6x1smAf_PAcC | isbn = 978-0-8311-3049-7}}</ref> Its usefulness arises from its insolubility in [[iron]], [[nickel]], and related [[alloy]]s at high temperatures, whereas diamond is soluble in these metals. Polycrystalline c-BN ('''PCBN''') abrasives are therefore used for machining steel, whereas diamond abrasives are preferred for aluminum alloys, ceramics, and stone. When in contact with oxygen at high temperatures, BN forms a [[Passivation (chemistry)#Surface passivation|passivation layer]] of boron oxide. Boron nitride binds well with metals due to formation of interlayers of metal borides or nitrides. Materials with cubic boron nitride crystals are often used in the [[tool bit]]s of [[cutting tool]]s. For grinding applications, softer binders such as resin, porous ceramics and soft metals are used. Ceramic binders can be used as well. Commercial products are known under names "[[Borazon]]" (by Hyperion Materials & Technologies<ref>{{cite web |title=Diamond and Cubic Boron Nitride (CBN) Abrasives |url=https://www.hyperionmt.com/products/Abrasives/mesh-cbn |website=Hyperion Materials & Technologies |access-date=21 June 2022}}</ref>), and "Elbor" or "Cubonite" (by Russian vendors).<ref name=b1/>

Contrary to diamond, large c-BN pellets can be produced in a simple process (called sintering) of annealing c-BN powders in nitrogen flow at temperatures slightly below the BN decomposition temperature. This ability of c-BN and h-BN powders to fuse allows cheap production of large BN parts.<ref name=b1/>

Similar to diamond, the combination in c-BN of highest thermal conductivity and electrical resistivity is ideal for [[heat spreader]]s.

As cubic boron nitride consists of light atoms and is very robust chemically and mechanically, it is one of the popular materials for X-ray membranes: low mass results in small X-ray absorption, and good mechanical properties allow usage of thin membranes, further reducing the absorption.<ref>{{cite journal |author1=El Khakani, M. A. |author2=Chaker, M. | title = Physical Properties of the X-Ray Membrane Materials | journal = Journal of Vacuum Science and Technology B | volume = 11 | pages = 2930–2937 | year = 1993 | doi = 10.1116/1.586563 | issue = 6 |bibcode = 1993JVSTB..11.2930E}}</ref>