CORRELATION BETWEEN THE INTERFACE STRUCTURE OF A TIN COATING DEPOSITED ONTO AISI 304 AND THE COATING ADHESION

Abstract

The interface between austenitic stainless steel AISI 304 and three different types of TiN coating, one with and two without an intermediate Ti layer, deposited using the triode evaporation ion plating technique, were characterized using cross-sectional transmission electron microscopy, glancing angle X-ray diffraction and resonant nuclear reaction analysis. A highly faulted interface due to the initial plasma nitriding of the substrates is observed for one type of deposition without the intermediate Ti layer. In this case a phase is formed at the interface between AISI 304 and the TiN coating, identified as expanded austenite. Scratch tests show poor coating adhesion of these samples. In contrast, a well adherent TiN coating can be deposited onto austenitic stainless steel without an intermediate Ti layer when the substrate material is not plasma nitrided and a defect-free interface is formed.