CORROSION RESISTANCE OF AUSTENITIC AND FERRITIC-AUSTENITIC STAINLESS STEELS AND NICKEL-BASED SUPERALLOYS

Abstract

Abstract: A comparative analysis of the corrosion behavior of austenitic and ferritic-austenitic (duplex) stainless steels and corrosion-resistant nickel-based superalloys is presented. The review covers general corrosion in H₂SO₄, HCl, and HNO₃, pitting and crevice corrosion, stress corrosion cracking, intergranular corrosion, erosion-corrosion wear, and electrochemical interactions. Nickel-chromium-molybdenum and nickel-chromium-molybdenum-tungsten alloys generally provide the broadest service envelope in reducing acids and chloride-containing environments. However, their advantages depend on the chemical composition, microstructure, weld condition, and electrode potential. Duplex stainless steels provide an effective balance among strength, resistance to localized corrosion, and cost. Consequently, the final material selection should be based on tests that reproduce the actual process and service conditions.