Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1470422 | Corrosion Science | 2010 | 10 Pages |
The effect of Mg2+ 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 Mg2+ concentration increases the population density and refines the grain size of the phosphate grains. In the presence of Mg2+, the phosphate coating is composed of mixed Zn phosphate hydrate and (Zn, Mg) phosphate hydrate. Furthermore, elevating Mg2+ in the solution reduces the porosity of the phosphate coating. As a result, the corrosion resistance of the phosphate coating is improved.
Research highlights► Mg2+ in the phosphate solution reduces pores in the phosphate coating on HDG steel. ► The phosphate coating with fewer pores display a better corrosion resistance. ► Mg2+ improves the corrosion resistance of phosphated HDG steel. ► Mg2+ distributes uniformly in Zn phosphate and (Zn, Mg) phosphate hydrate coating. ► Mg2+ accelerates the nucleation of (Zn, Mg) phosphate by enhanced impingements.