Corrosion Protection Mechanism of Carbon Steel by Corrosion Products on Surface of Thermally Sprayed Zinc Coating

Abstract

Influence of corrosion of carbon steels by corrosion products of the thermally sprayed zinc coating were studied by means of immersion test and electrochemical technique in 1/20 mol/dm³ Na₂SO₄ solution at 303K.Zinc carbonate(ZnCO₃)and Zinc oxide(ZnO)powders of the commercial reagent produced a slurry form.Slurry particles were deposited onto carbon steel sheets.The corrosion rate of carbon steel,which was measured by weight losses,decreased in order:Fe > ZnCO₃/Fe > ZnO/Fe.After the immersion test of ZnO/Fe,zinc metal was deposited on the carbon steel surface.The corrosion of carbon steel was dependent on the reduction reaction of the dissolved oxygen and the precipitation reaction of zinc.