ANALYSIS OF THE COMPATIBILITY OF PLASMA-NITRIDED STEELS WITH CERAMIC COATINGS DEPOSITED BY THE ION-PLATING TECHNIQUE

Currently there is a trend towards deposition of thin films such as Ti N or CrN on plasma-nitrided steels. This combination should enhance th e surface properties and fatigue strength of the treated parts, but ma ny problems have yet to be overcome and, in particular, the formation of a thin soft layer of ferrite located at the coating and gamma' or e psilon compound layer interface. We present results on the formation o f this interfacial film complementary to the results already published . We investigated the influence of the coating conditions on the struc tural stability of nitrided layers and found that the compatibility of these two treatments depends not only on the thermal sequence of the coating process but also on the ion bombardment during the etching ste p of the coating process.