Study on Corrosion Behavior of T-22 Alloy in Ultrahigh Temperature Impure Helium and Air

Abstract

T-22 alloy is an alternative material for heat transfer tube of steam generator of high temperature gas cooled reactor. The corrosion behavior of T-22 alloy in high temperature impure helium and air at 950 °C was studied. After the experiment, the experimental results were analyzed by electronic balance, scanning electron microscope (SEM), X-ray energy dispersive spectroscopy (EDS) and carbon sulfur analyzer. The results show that the corrosion phenomena and mechanisms of T-22 alloy in the atmosphere of extreme low oxygen partial pressure and extreme high oxygen partial pressure are quite different. There was no obvious oxide layer on the surface of T-22 alloy after corrosion in impure helium, and Fe elements did not participate in the oxidation reaction. After corrosion, the alloy had slight mass loss and complete decarburization. After the corrosion of T-22 alloy in air, a large number of Fe elements participated in the oxidation. After the experiment, the oxide layer of the alloy fell off, and the mass gain was very obvious. The alloy was seriously corroded and damaged.