Investigation on the oxidation and corrosion behaviors of FeCrZr alloy as a protective material for Zr cladding

The oxidation and corrosion resistance of the FeCrZr (Fe 44, Cr 22 and Zr 34 in wt.%) alloy were evaluated as a possible coating material for Zr alloy. During exposure to air at 800 °C-1204 °C, the FeCrZr alloy showed a better oxidation resistance compared with Zr alloys. It was found that the oxidation behavior was mainly controlled by the diffusion of iron, nitrogen, and oxygen, and ZrN was formed in the oxide scale at high temperature. Meanwhile, the FeCrZr showed a better corrosion resistance than Zr alloys when corroded in 400 °C/10.3 MPa steam for 30 days. The hardness and fracture toughness of the as-melted FeCrZr are 8.5 GPa and 1.54 MPa m1/2 at room temperature, respectively. After annealing at 600 °C, the hardness increases up to 9.8 GPa and the fracture toughness reached 3.26 MPa m1/2, which were attributed to the formation of Fe2Zr Laves phase and ductile Fe-Cr phase. Thermo-physical tests revealed that the coefficient of thermal expansion was about 8.2 × 10−6/°C, and the melting point was higher than 1500 °C. Finally, the feasibility of the FeCrZr alloy as Zr alloy coating was discussed.