CORROSION OF SPUTTERED W-NI-N HARD COATINGS IN CHLORIDE MEDIA

The corrosion behaviour of sputtered W-Ni-N hard coatings of 4 mu m an d 8 mu m thickness on high speed steel substrates and with different p ercentages of nitrogen has been evaluated by electrochemical technique s in aqueous chloride solution and by scanning electron microscopy. It was found that the incorporation of nitrogen in the films increases t he corrosion resistance. Corrosion occurs mainly by Fitting through to the substrate; in comparison to similar W-Ti-N coatings, the corrosio n rate is greater. (C) 1997 Elsevier Science S.A.