Application of Magnesium-Manganese Phosphate Coating on Low Carbon Steel

A novel magnesium-manganese phosphate coating was applied on low carbon steel from a phosphate solution at different temperatures. The composition and surface morphology of the coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. Potentiodynamic polarization curves were used to examine the corrosion resistance of the coating. It was observed that the coating consists of Newberyite, Hureaulite and manganese hydrogen phosphate hydrate. The experimental results indicated that the coating had fine crystals forming a dense coating at 90 ºC. As a result, improvement of the corrosion resistance of the low carbon steel by the phosphate conversion treatment was achieved.