azanylidynetitanium

Titanium nitride (TiN) (sometimes known as “Tinite” or “TiNite” or “TiN”) is an extremely hard ceramic material, often used as a coating on titanium alloys, steel, carbide, and aluminium components to improve the substrate's surface properties.
Applied as a thin coating, TiN is used to harden and protect cutting and sliding surfaces, for decorative purposes (due to its gold appearance), and as a non-toxic exterior for medical implants. In most applications a coating of less than 5 micrometres (0.00020in) is applied.