TEM study on oxide mechanism of the dissimilar welds between 316 stainless steels/Inconel 182 in high temperature and high pressure water

Oxidation mechanism on the dissimilar welds in high temperature and high pressure water was investigated. The results indicated that there were different types of duplex-structural oxide layers on both sides of the fusion boundary. In external oxide layer, spinel oxide appeared on 316 SS side, while a component of flaky and spinel oxides deposited on Inconel 182 side. In inner oxide film, galvanic corrosion occurred between 316 SS and Inconel 182 sides, which led to formation of spinel oxide rather than Cr2O3 on 316 SS side, and some holes between these spinel oxides, while spinel oxide and Cr2O3 formed on Inconel 182 side.