Plasma-assisted deposition of a three-layer structure by vacuum and gas arcs

The durability and adhesion of thin coatings often depends on the structure and properties of the layer intermediate between the coating and the subst rate, especially in the case where the layer and the substrate are highly d ifferent in microhardness, With a vacuum are and a hot-cathode are, a proce ss has been arranged which involves cleaning of the surface, nitration of t he article, and deposition of a coating. As a result, a three-layer composi tion has been produced which consists of a TiN layer of thickness up to 5 m u m and microhardness 20 GPa, an intermediate Fe4N layer of thickness up to 8 mu m and microhardness 7.5 GPa, and a nitrated layer of thickness up to 100 mu m with a gradually varying microhardness. With the TiN layer showing high adhesion, the coating has a durability three of four times greater th an that of a coating produced with the use of a conventional technology.