ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY OF NITROGEN-SPUTTER AND CARBON-SPUTTER COATED 316-L STAINLESS-STEEL

The effect of nitrogen and carbon sputter coatings on the electrochemi cal behaviour of 316 L stainless steel in a simulated physiological so lution (Hank's Balanced Salt Solution) was studied by electrochemical impedance spectroscopy with the aim of characterizing the surfaces and choosing the best coating. Coatings with different thicknesses and st ructures were tested. The results showed that thicker sputter coatings produce surfaces with higher charge transfer resistance and lower int erface capacities. This indicates that these materials probably owe th eir high corrosion resistance to the formation of more protective film s. (C) 1997 Elsevier Science Ltd.