Correlation Between Localized Corrosion Morphology And TheState Of Interface Of Coated TiN Thin Film.

Abstract

Ceramic thin film was widely used due to its superior mechanical and chemical characteristics. However, defects and micro cracks were always existed from the initial stage. In corrosive environment. these defects caused the problem of localized corrosion. Moreover, the evaluations of changes of structure and the state of interface between thin film and substrate which was brought about through employing different coating methods become extremely important. Therefore, TiN thin film coating used in this study was made by two different types of coating methods, that is, plasma CVD and Dynamic Ion Mixing (DIM), which have different interfacial strength. Then, defect morphology and nm or pm orders localized corrosion generated in 3% NaCl aqueous solution was investigated by Atomic Force Microscopy (AFM). As a result, in TiN film coating made by the plasma CVD method, exfoliation of film itself was recognized from the initial stage. The crevice corrosion has been developed from this exfoliation. On the other hand, exfoliation of film itself was not confirmed in thin film coated by the DIM method. Therefore, differences in the initial state of film structure and the generated corrosion morphologies from those defects were observed. And also, improvements in corrosion and exfoliation resistances were recognized in case when superior adhesive state of interface betw.een TiN thin film and substrate were realized. Transactions on Engineering Sciences vol 33, © 2001 WIT Press, www.witpress.com, ISSN 1743-3533