Corrosion Behaviour of Superalloys-Based Ni and Co Employing Electrochemical Noise

Abstract

Superalloys have basic elements like Fe, Ni and Co, the principal applications are in the hottest zones of turborreactors, nuclear reactors, petrochemical equipment and rockets. The aim of this paper is analysing the corrosion resistance of these superalloys in acid electrolytes using electrochemical noise technique. Superalloys evaluated was Waspaloy and Ultimet in H2SO4 and NaCl at 3.5% with two different temperatures, 25 and 60°C. Electrochemical noise technique monitored 1024 data per seconds, obtaining electrochemical parameters like noise resistance (Rn), corrosion current (icorr) and corrosion type using localization index (LI). The results of LI show that superalloys presented localized corrosion in all experiments.