Corrosion behavior of heat-resistant stainless steel in high temperature molten glass

Abstract

The development of the nuclear industry and nuclear energy have prompted studies focusing on disposal of nuclear waste in a green and safe way. The use of metal containers to fill glass solidified nuclear waste and then landfill is currently the dominant way in waste disposal. However, the high temperature corrosion caused by the high temperature molten glass on the surface of the metal container becomes an important factor accelerating the failure of the container. Therefore, an in-depth understanding of the corrosion behavior of metals in high temperature molten glass is necessary to ensure the safety of disposal of nuclear waste.The S30815 heat-resistant stainless steel was selected as the research object, and the corrosion morphology, composition and phase structure of the S30815 heat-resistant stainless steel kept in 1100 ℃ molten glass for different time were deeply analyzed. The results show that the molten glass corrodes inward along the grain boundary into the matrix and molten glass gradually replaces the steel by occupying the grain boundary and further penetrates the grains to form corrosion pits. Cr and Si elements in the heat-resistant stainless steel diffuse into the molten glass during corrosion, resulting in a decrease of content at the surface, and finally promote the transformation of metal surface from austenite to martensite. The corrosion of heat-resistant stainless steel by molten glass is alkaline dissolution. A continuous and stable oxide film cannot be formed on the surface, which means the corrosion will continue with the extension of holding time.

Keywords

• s30815
• heat-resistance stainless steel
• molten glass
• high temperature corrosion