The influence of second phase particles on the crack formation in oxide films formed on zirconium alloys

The oxidation behavior of second phase particles (SPPs) and the formation of cracks in oxide films on Zr-0.93Sn-0.82Nb-0.17Fe-0.019S alloy in lithiated water with 0.01 M LiOH were investigated. Results show that direction of crack propagation in the oxide films coincides with stringer direction of SPPs, indicating a close relationship between the crack formation and SPPs distribution. β-Nb particles along the cracks are oxidized faster as compared to those separating the crack. Therefore, the formation of cracks along the stringer can accelerate oxidation of SPPs, which in turn can encourage the formation of cracks in oxide films.