HARDNESS AND CORROSION-RESISTANCE OF SINGLE-PHASE NITRIDE AND CARBIDEON IRON

With ion beam synthesis, closed homogeneous nitride and carbide layers have been produced. The hardness and the corrosion resistance potenti al of gamma'-Fe4N, epsilon-Fe2.6N and Fe3C cementite single-phase laye rs have been determined. The results are compared with samples implant ed in a conventional way with the same N concentration, resulting in p recipitates, and with untreated iron. The hardness is found to be incr eased by a factor of 2.5 in comparison with pure iron; no significant difference between the different samples is found. In cyclovoltammetri c tests, the dissolution of iron is found to be suppressed considerabl y by three orders of magnitude for gamma'-Fe4N, 1.5 for cementite and 1 for epsilon-Fe2.6N, while implantation of precipitates even promotes the corrosion.