Plasma-based surface engineering processes for wear and corrosion protection

Vacuum plasma-based coating and treatment methods have considerable potential for reducing wear and corrosion. However, they have not been widely applied to engineering components other than tools such as those used in metal cutting. This is due to several factors, not least of which are cost and an unsuitability for cheaper substrate materials. Here we discuss six plasma-based processing routes that can widen the applicability of these processes and ensure greater market penetration. These methods are: (i) duplex plasma nitriding plus physical vapor deposition (PVD) coating, (ii) low temperature plasma diffusion treatment, (iii) postcoat plasma nitriding, (iv) layered diamondlike carbon/metal carbide PVD/chemical vapor deposition coating, (v) thick metal/metal nitride PVD coating, and (vi) duplex electroless nickel plus PVD coating. The characteristics of these methods are discussed, especially with regard to their beneficial influence on wear or corrosion.