Concentrated (50%) hydrogen peroxide solutions are stored and shipped in aluminum or stainless steel vessels. Aluminum is sensitive to pitting corrosion in this environment if ppm levels of chloride are present. This is counteracted by the addition of inhibitors such as nitrates. Whether a given inhibitor concentration gives adequate protection against the level of chloride present can be determined usually only by lengthy testing, since the pitting corrosion becomes visible only after a long induction period.
This paper describes attempts to devise a rapid electrochemical technique to detect the aggressive behavior of chloride in aluminum-hydrogen peroxide environments and to determine the degree to which nitrate addition counteracts it. Techniques used are a modification of Hirozawa’s “galvanostaircase polarization” method and a “potential titration" using a controlled chloride addition rate.
