Chromium nitride is a chromium and nitrogen chemical compound with the formula CrN. It is very hard and is extremely resistant to corrosion. It is an interstitial compound, with nitrogen atoms occupying the octahedral holes in the chromium lattice: as such, it is not strictly a chromium(III) compound nor does it contain nitride ions (N3−). Chromium forms a second interstitial nitride, dichromium nitride, Cr2N.
Occurrence Though rare, carlsbergite - the natural form of chromium nitride - occurs in some meteorites.
Synthesis Chromium(III) nitride can be prepared by the direct combination of chromium and nitrogen at 800 °C:
2 Cr + → 2 CrN
It can also be synthesized by physical vapor deposition techniques such as cathodic arc deposition.
Applications CrN is used as a coating material for corrosion resistance and in metal forming and plastic moulding applications. CrN is often used on medical implants and tools. CrN is also a valuable component in advanced multicomponent coating systems, such as CrAlN, for hard, wear-resistant applications on cutting tools.
Magnetism The fundamental materials physics of CrN, giving rise to its favorable properties, has been debated recently in high-profile scientific journals such as Nature Materials. In particular, the importance of magnetism in both the low temperature and the high temperature phases has been demonstrated by using quantum mechanical calculations of the compound's electronic structure.
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