NbN

NbN, or niobium nitride, is a chemical compound consisting of niobium and nitrogen with the formula NbN. It is typically described as a hard, refractory ceramic with a rock-salt type crystal structure at ambient conditions. NbN is noted for its combination of high hardness and wear resistance, very high melting point, chemical stability, and metallic electrical conductivity. In addition, NbN is a superconductor, with a superconducting transition temperature around 16 kelvin and a relatively high upper critical field, properties that have made NbN films important in superconducting electronics and photon-detection applications.

Synthesis and forms: NbN can be formed by direct nitridation of niobium or by reactive deposition methods such as sputtering or chemical vapor deposition from niobium-containing targets in a nitrogen-containing atmosphere. The NbN phase is commonly produced as thin films with controlled stoichiometry NbN or NbNx; properties depend on nitrogen content and microstructure. Off-stoichiometric compositions can yield other niobium nitride phases such as Nb2N.

Applications: NbN is widely used as a protective coating for cutting tools and wear parts due to its hardness and corrosion resistance. In electronics, NbN thin films are employed in superconducting circuits, superconducting radio-frequency cavities, and detectors, including superconducting nanowire single-photon detectors, where low-temperature operation enables fast, low-noise performance.

Safety and handling: NbN is generally treated as a refractory ceramic material; standard precautions for high-temperature nitride processes and nitrogen atmospheres apply, including adequate ventilation and proper handling of process gases.

See also: niobium, nitrides, superconductivity.