2012 Volume 61 Issue 2 Pages 48-51
Copper tubes were immersed for up to 18 months in synthetic freshwaters containing silica to investigate the effect of silica, chloride and sulfuric ion on corrosion behavior and pitting morphology of copper. Pitting corrosion similar to the moundless type pits occurred on the surface of the copper tubes immersed in the water containing 20 or 40 ppmSiO2, 10 ppmCl− and 10 ppmSO42−. The surface of the copper tube immersed in the water containing 80 ppmSiO2 was covered with white granular scales. The depth of pitting corrosion occurred in the water containing 80 ppmSiO2 was smaller than those of pits occurred in the water containing 20 or 40 ppmSiO2. The concentration of silica in the synthetic water containing 20 ppmSiO2 decreased to about 2 ppm for 9 months when the copper tubes were immersed in the synthetic water.