Correlations between Oxide Structure, Iron Distributions, and Zirconium Oxide Growth

Waterside corrosion and associated hydrogen generation remain a major limiting factor for the use of zirconium alloys as cladding materials under severe fuel duty conditions. Although it has been observed that minor alloying additions might significantly affect the corrosion response of Zr alloys, the origins for these differences remain unclear. To develop alloys with greater corrosion resistance, it is important to understand the correlations between alloying additions, oxide structure and the oxidation behavior of zirconium alloys. Three alloys were examined: pure Zr (0.009 wt.% Fe), Zircaloy-4 (1.32 wt.% Sn, 0.19 wt.% Fe, and 0.09 wt.% Cr) , and a ZrFeCr alloy (0.38 wt.% Fe and 0.22 wt.% Cr). All three alloys were corroded in autoclaves in 360°C water. Pure Zr loses protectiveness relatively early (