High power pulsed magnetron sputtered CrNx films

The deposition of chromium nitride coatings by means of a glow-discharge at power densities up to 3000 W/cm2 in both inert and reactive gas atmospheres, is described. The incident particles are up to 30% ionised, a far higher percentage than would normally be found in magnetron sputtering. High-speed steels and stainless steels are etched, prior to coating, by application of a bias voltage of - 1200 V. As TEM images show, the interfacial region remains clean and free from interfering crystalline or re-crystallised phases. The structure of the deposits are polycrystalline and columnar. The corrosion resistance of the coating is excellent, and results are also shown for the crystal structure, internal stress, hardness and wear.