The crevice corrosion behavior of XTO steel was investigated with a wedge-shaped crevice assembly under -1000 m V （SCE） cathodic polarization in the solutions with various HCO3 concentrations. The potential, current...The crevice corrosion behavior of XTO steel was investigated with a wedge-shaped crevice assembly under -1000 m V （SCE） cathodic polarization in the solutions with various HCO3 concentrations. The potential, current, pH and the oxygen content within the crevice were measured with or without outside coupled specimen. The results indicated that the polarization potential of XTO steel in the crevice dropped with the increase of time under the cathodic polarization. There was a remarkable influence of HCO3 concentration on the potential of XTO steel in the crevice. When HCO3 concentration was up to 0.125%, the surface of the metal was covered with the corrosion products that resulted in the polarization extent of XTO steel decreased. The pH value in the crevice rose and it dropped gradually from the crevice mouth to the bottom under the cathodic polarization. With the increasing of HCO3 concentration, the hydrolyzation reaction of metal in the crevice bottom aggravated. Most of the dissolved oxygen in the crevice was consumed by the cathodic current. The maximum cathodic current on the metal surface was at the crevice mouth and it was much more than that at the crevice bottom.展开更多
基金the National R&D Infrastructure and Facility Development Program of China(No.2005DKA10400)Financial support from the National Key Technology R&D Program of China (No.2006BAKO2B01-06)is also acknowledged.
文摘The crevice corrosion behavior of XTO steel was investigated with a wedge-shaped crevice assembly under -1000 m V （SCE） cathodic polarization in the solutions with various HCO3 concentrations. The potential, current, pH and the oxygen content within the crevice were measured with or without outside coupled specimen. The results indicated that the polarization potential of XTO steel in the crevice dropped with the increase of time under the cathodic polarization. There was a remarkable influence of HCO3 concentration on the potential of XTO steel in the crevice. When HCO3 concentration was up to 0.125%, the surface of the metal was covered with the corrosion products that resulted in the polarization extent of XTO steel decreased. The pH value in the crevice rose and it dropped gradually from the crevice mouth to the bottom under the cathodic polarization. With the increasing of HCO3 concentration, the hydrolyzation reaction of metal in the crevice bottom aggravated. Most of the dissolved oxygen in the crevice was consumed by the cathodic current. The maximum cathodic current on the metal surface was at the crevice mouth and it was much more than that at the crevice bottom.
