Abstract
► Mg 2+ in the phosphate solution reduces pores in the phosphate coating on HDG steel. ► The phosphate coating with fewer pores display a better corrosion resistance. ► Mg 2+ improves the corrosion resistance of phosphated HDG steel. ► Mg 2+ distributes uniformly in Zn phosphate and (Zn, Mg) phosphate hydrate coating. ► Mg 2+ accelerates the nucleation of (Zn, Mg) phosphate by enhanced impingements. The effect of Mg 2+ in the phosphate solution on the microstructural evolution and corrosion resistance of the coating on hot-dip galvanized steel has been explored. Surface morphology observations reveal that increasing the solution Mg 2+ concentration increases the population density and refines the grain size of the phosphate grains. In the presence of Mg 2+ , the phosphate coating is composed of mixed Zn phosphate hydrate and (Zn, Mg) phosphate hydrate. Furthermore, elevating Mg 2+ in the solution reduces the porosity of the phosphate coating. As a result, the corrosion resistance of the phosphate coating is improved.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
