The high temperature corrosion of Incoloy 800H alloy at three different atmospheres

Abstract

ABSTRACT Incoloy 800 H alloy is one of the candidate materials for high-temperature gas-cooled reactor steam generator heat transfer tubes. Previous studies have shown that corrosion phenomena such as oxidation and carburization occurred in high-temperature impure helium gas. On this basis, the corrosion behavior of Incoloy 800 H alloy in air, impure helium, and vacuum was investigated. After the experiment, electronic balance, scanning electron microscope, X-ray energy spectrum analysis, X-ray diffraction analysis, and gas chromatograph were used to characterize the corrosion behavior of the alloy. The results showed that CO is the main oxidation and carburization gas of Incoloy 800 H alloy in impure helium. Contents in ppm CO2 can supplement the reduction of CO and prevent the destruction of oxidation layer and carburization layer; The mass change of the alloy after corrosion in air at 950°C met the oxidation parabola law, the corrosion layer on the alloy surface fell off, and Si migration and accumulation in different degrees occurred in air and impure helium experiments; Carbon transfer and decarburization occurred in the alloy in a vacuum.