Corrosion of stainless steels in NaCl-KCl based melts

Abstract

Corrosion behavior of stainless steel types AISI 316L, 316Ti and 321 was studied at 750 °C in NaCl-KCl equimolar melts. Iron, chromium and manganese species constitute the major corrosion products. The following mechanism of stainless steel corrosion in molten chlorides was proposed: 1) chemical interaction between the alloy and the salt intensified by the formation of microgalvanic pairs; 2) formation of chromium and molybdenum carbide-containing phases in steel as a result of heating to 750 °C; 3) additional formation of galvanic pairs between the grains of austenitic alloys and the carbide phases at the grain boundaries resulting in enhanced intergranular corrosion. ©The Electrochemical Society.