Relationship between Chromia Solubility and Superalloy Corrosion in Silicate Melts – A First Attempt

Abstract

Most of equipments used in glass industry are superalloys containing up to 30 wt% chromium. The ability of these alloys to resist against silicate melt corrosion is directly linked to the formation of a chromia (Cr2O3) layer at the alloy/melt interface which can be protective under particular conditions. These conditions have been previously identified and are the temperature, melt composition and redox conditions. The aim of the present study is to establish the relationship between the protective (or non protective) behaviour of the chromia layer with the solubility of chromia in silicate melts under given conditions. The combination between results from the electrochemical study of pure chromium corrosion and total Cr solubility in Na2O-xSiO2 melts clearly indicates that both parameters are linked: the lower the total Cr solubility, the better the Cr is corrosion resistant.