The process of surface saturation of metallic materials with nitrogen. The aim is to obtain a high surface hardness and tough core. Unlike cementing, hardness is achieved by saturating the surface with nitrogen – without subsequent heat processing. The high level of hardness is due to the occurrence of very hard nitrogen chemical compounds with iron and various additive elements. The following properties can be achieved by nitriding:
- high level of surface hardness
- high resistance to mechanical wearing
- high fatigue limit (for steels)
- increased resistance to cavitation and corrosion
- high fireproofness (various steels and hard melting metal alloys).
Nitriding hard layers are formed with a thickness of up to 0.5 mm and the growth rate of the surface layer reaches up to 0.01 mm per hour.