Effect of the electrolyte composition on the corrosion of 12Kh17 steel in molten alkali metal carbonates

Abstract

The corrosion of 12Kh17 steel in the melts of alkali metal carbonates containing additions of various chemical types is studied using anodic potentiostatic polarization. The morphology of the 12Kh17 steel surface is analyzed by electron-probe microanalysis. The introduction of corrosion passivators and activators affects the mechanism of local corrosion damages. The corrosion of the steel proceeds according to an electrochemical mechanism. Carbonate anions serve as oxidizers of the steel along with oxygen dissolved in the melt. Treatment of a corrosive medium can be used to protect metallic constructions against corrosion in high-temperature salt electrolytes. Combined introduction of corrosion activators and passivators in a salt phase makes it possible to form protective layers with a high corrosion resistance.