Effect of minor alloying elements on the corrosion behavior of Fe40Al in NaCl-KCl molten salts

Abstract

The hot corrosion behavior of Fe40Al intermetallic alloyed with Ag, Cu, Li, and Ni (1-5 at.%) in NaCl-KCl (1: 1 M) at 670°C, typical of waste gasification environments, has been evaluated by using polarization curves and weight loss techniques and compared with a 304-type stainless steel. Both gravimetric and electrochemical techniques showed that all different Fe40Al-base alloys have a much higher corrosion resistance than that for stainless steel. Among the different Fe40Al-based alloys, the corrosion rate was very similar among each other, but it was evident that the addition of Li decreased their corrosion rate whereas all the other elements increased it. Results have been explained in terms of the formation and stability of an external, protective Allayer. © 2012 G. Salinas et al.