HCD法によるTiNコーティング鋼の耐食性に及ぼす成膜条件の影響

抄録

TiN films were deposited under different bias voltages onto SUS304 stainless steel substrates by a hollow cathode discharge (HCD) type ion plating process. The corrosion resistance of the TiN-coated specimens in the active region was estimated in aqueous solutions of sulfuric acid, mainly by an electrochemical method. The adherence between the TiN film and stainless steel substrate was improved by applying a bias voltage, and the films deposited using a bias voltage exhibited a dense and distinct columnar structure. Measurements of the anodic polarization curves showed that the critical current density for passivation of the TiN-coated specimens was smaller than that for specimens without a TiN coating, that is, that active dissolution was retarded by TiN coating. The corrosion resistance of the TiN-coated specimens was further improved by applying a bias voltage, and this is attributed to the fact that the bias voltage decreased the amount of defects in the TiN films, that is, increased the intercepting effect of the film from it's surroundings. A compressive stress existed in the TiN films, the magnitude of which depended on the bias voltage. Moreover, there appeared to be good a correlation between the residual stress in the film and the corrosion resistance of the coated specimens.