Temperature-Dependent oxidation of Zr-Sn-Nb zirconium alloys in LOCA conditions at Elevated temperatures

The oxidation behavior of Zr-1.0Sn-1.0Nb alloy in both steam and oxygen atmosphere was studied from 600 ℃ to 1100 ℃ using a simultaneous thermogravimetric analyzer. The results show that a clear, definite and systematic oxidation transitions occurred within the experimental duration. In both steam and oxygen atmospheres, the oxidation transition duration of N36 decreased with increasing temperature, highlighting the significant influence of temperature on the oxidation process. Over a wide temperature range up to 1050 ℃, the oxidation transition time was found to follow an Arrhenius relationship with temperature. The oxidation of N36 is more severe in the oxygen atmosphere than that in the steam atmosphere, as evidenced by a shorter oxidation transition time and a thicker oxide film at the same condition. However, the similar activation energies suggest a common in both atmospheres. By comparing the exponent (n) in oxygen and steam atmospheres, the exponent (n) in oxygen is smaller than that of steam, proving that oxide scale in oxygen is more prone to breakaway, leading to an earlier transition or faster oxidation kinetics in the oxygen atmosphere.