The corrosion resistance of 80 wt. % Ni-20Cr coating applied by the powder flame thermal
spray technique on AISI 304 stainless steel has been evaluated in 80 mol % Na2SO4-20V2O5
molten salt using electrochemical techniques. The testing temperatures were 700, 800 and
900°C, and the electrochemical techniques included potentiodynamic polarization curves
(PPC) and electrochemical noise (EN). The objective of this research was to obtain the
corrosion mechanism from the EN technique and polarization curves. The current and potential
time series data were analyzed in the time domain. A SEM analysis of the corroded samples
demonstrated that at 900°C a mechanism of sulfur penetration into the substrate was the most
important corrosive attack. According with the electrochemical results, the 80 wt. % Ni-20Cr
coating suffered localized corrosion and mixed corrosion, determining that the major localized
corrosion was observed at the higher temperature.