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Passive films formed on Type 304 and 316 stainless steels under a wet-dry cyclic condition were characterized using X-ray photoelectron spectroscopy (XPS). Cr enrichment in the passive films during early stage of the wet-dry cycles occurred due to the preferential oxidation of Cr and the selective dissolution of Fe. However, the Cr fraction of hydroxide layer in passive film gradually decreased with time, because Fe(OH)aq dissolved in the thin water layer were accumulated into the outermost hydroxide layer of a passive film during the dry condition. Chloride in thin water layer facilitated selective dissolution of Fe ions. On the other hand, the Mo in Type 316 stainless steel suppressed the dissolution of Fe ions. Consequently, Cr fraction in passive film on Type 316 became smaller than that of Type 304 stainless steel.

The surface of commercial carbon black was modified by pyrolysis of acetonitrile in attempt to obtain the graphitic carbon coating layer. It was confirmed that the surface of carbon black was partially graphitized, having 0.23 of graphitization index and 1.87 nm of mean stack height. From the electrochemical oxidation test of carbon, the carbon-coated carbon black showed higher corrosion resistance than the untreated carbon black although the core of the carbon black support still remained untreated. When it was applied to the support for platinum electrocatalyst, the enhanced stability was observed. From those corrosion tests as well as XPS results, it can be suggested that the partially crystalline graphitic carbon surface facilitates the relatively more reduced surface of platinum.

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