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

In this paper, the effects of scaling ions (Ca2+ and Mg2+) 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 Zn2+ and OH− affected the nuclei formation of scale. The corrosion products and scale were identified as Zn(OH)2, ZnO, CaCO3 and MgCO3, respectively. When scale formed on the galvanized steel pipe, the corrosion rate slowed down and the pitting region became smaller.