Plasma nitriding of aluminium@ (alloy) components - at temps. below component m.pt., producing very hard, wear- and corrosion-resistant aluminium nitride coatings

摘要

Alumium (alloy) components undergo plasma nitriding, producing very hard, wear- and corrosion-resistant aluminium nitride protective coatings. The first stage involves cleaning of the component surface in an atmosphere of Ar, N2 or NH3, and subsequent removal of the natural oxide layer by sputtering. The second stage comprises nitriding of the aluminium, (or alloy) component in nitriding media (NH3, NH3/N2, NH3/H2 or N2/H2) by N2 in the form of a plasma. Plasma temperature is 350 deg.C-50 K below the m.pt. of the component material (or its lowest m.pt. grain-boundary impurities). Plasma nitriding is performed in conventional plasma nitriding equipment. USE/ADVANTAGE - Surface-coating of components used in pneumatic and hydraulic systems. Durability of the aluminium nitride coating is several times greater than that of eloxation coating