Effect of interface undulation on the high temperature oxidation behaviors of grit-blasted and coated zircaloy in pressurized water

Highlights: • The grit-blasted and coated zircaloys present higher corrosion rate than the as-received substrate during early stage. • Interface undulation can result in redistribution of the oxide growth stress of zircaloy. • Local stress concentration induces initiation of cracks and therefore increases the corrosion rate of zircaloy. Effect of interface undulation on the high-temperature oxidation behaviors of grit-blasted and coated zircaloys in pressurized water was investigated. The grit-blasted and the coated zircaloy substrates present significantly higher corrosion rate than the as-received flat substrate during the early stage of exposure. Numerical analysis suggests the interface undulation results in redistribution of the oxide growth stress of zircaloy, as well as varying the local stress concentration, which induces initiation of cracks and therefore increases the corrosion rate of zircaloy. Propagation of cracks along the interface drives delamination of the protective coating. Results of this work not only promote understanding of the coating/substrate interface evolution in high-temperature pressurized water, but also provide a guide to design corrosion-resistant zirconium alloys and/or coatings for fuel cladding.