XPS and TEM characterization of oxides formed in simulated primary water on steam generator tubes made of Ni based alloy

Corrosion of Ni-based alloy steam generator tubes in simulated primary water leads to the formation of oxides on the surface of the tubes and to the release of corrosion products. The oxides formed on two industrial samples were studied using X-ray photoemission spectroscopy and transmission electron microscopy. The morphology, structure and composition of the oxide layers were determined, and the differences observed were discussed in relation to previous analyses on the as-received inner surfaces. A fine grains layer, alumina on the surface of native oxides could influence the behavior of the surface in primary water.