Differentiation in corrosion performance of alumina forming alloys in alkali carbonate melts

Alkali carbonate melts are promising high temperature thermal storage media. In this work five alumina forming alloys have been exposed to a ternary LiNaK melt and CO2 at 800 °C. The corrosion propagation was found depend on the formation of slow-growing LiAlO2 scale. Furthermore, two polymorphs contributing phase were monitored for up 1000 h: dense α-LiAlO2 scale γ-LiAlO2 crystallites. We suggest growth stress assisted relaxing into outwards growing phase. This implies deceleration towards steady state-thickness.