Effect of Surface Conditions and Specimen Composition on Hydrogen Permeation Behavior of Coated and Uncoated Steels during Wet and Dry Corrosion at a Constant Dew Point

摘要

A wet and dry corrosion test with a constant dew point was applied to investigate the effects of scratches and specimen composition on the hydrogen permeation behavior of Zn and 55 mass% Al–Zn coated steels as well as of uncoated steel. There was an etched size controlled scratch formed on specimens with a laser machining technique. The hydrogen permeation current was observed to be independent of the specimen composition and the area of the formed scratches, the corrosion products were observed after the tests. The hydrogen permeation current of the steels with the formed scratches decreased with number of cycles of the wet and dry tests. Except in the first cycle there were no significant changes in the current with cycle number on steels without formed scratches. It was suggested that the composition, scratch, and corrosion products play an important role in the hydrogen permeation behavior during wet and dry corrosion.