Corrosion behavior of Alloy 800 (UNS N08800) in the presence of hydrogen peroxide is important
because of its potential application in the future power plants. The aim of this study is to evaluate how
local variation of pH alters both the electrochemical reduction of hydrogen peroxide and
electrochemical corrosion behavior of Alloy 800 in sulfate solutions. Cathodic polarization test was used
to evaluate the kinetics of reduction of hydrogen peroxide. Linear polarization resistance,
electrochemical impedance spectroscopy and potentiodynamic polarization tests were used to study
the corrosion behavior in presence and absence of buffering agent. The results show that the reduction
of hydrogen peroxide in the presence of KH2PO4 as the buffering agent show two cathodic waves while
only one cathodic wave is observed in the unbuffered solutions. The polarization resistance obtained by
linear polarization resistance method was decreased from 50 kO cm2 to 7 kO cm2 by introduction of the buffering agent. These results were consistent with the impedance spectra trend.
Key words: iron-nickel-chromium alloys, hydrogen peroxide, corrosion