Effect of Ca2+and Mg2+ on corrosion and scaling of galvanized steel pipe in simulated geothermal water

Abstract In this paper, the effects of scaling ions (Ca 2+ and Mg 2+ ) on corrosion and scaling processes of galvanized steel pipe in geothermal water are presented. Spherical corrosion products and needle-shaped scale coexisted on the pipe surface. The concentration of Zn 2+ and OH − affected the nuclei formation of scale. The corrosion products and scale were identified as Zn(OH) 2 , ZnO, CaCO 3 and MgCO 3 , respectively. When scale formed on the galvanized steel pipe, the corrosion rate slowed down and the pitting region became smaller.