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 TiN or CrN on plasma-nitrided steels. This combination should enhance the surface properties and fatigue strength of the treated parts, but many 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 epsilon compound layer interface. We present results on the formation of this interfacial film complementary to the results already published. We investigated the influence of the coating conditions on the structural 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 step of the coating process.