Preparation of Phytic Acid/Silane Hybrid Coating on Magnesium Alloy and Its Corrosion Resistance in Simulated Body Fluid

In order to decrease the corrosion rate and improve the bioactivity of magnesium alloy, phytic acid/saline hybrid coatings were synthesized on AZ31 magnesium alloys by sol–gel dip-coating method. It was found that the mole ratio of phytic acid to γ-APS had a great influence on coating morphology and the corresponding corrosion resistance of the coated magnesium alloys. When the mole ratio of phytic acid to γ-APS was 1:1, the obtained hybrid coating was integral and without cracks, which was ascribed to the strong chelate capability of phytic acid and Si-O-Si network derived from silane. Electrochemical test result indicated that the corrosion resistance of the coated magnesium alloy was about 27 times larger than that of the naked counterpart. In parallel, immersion test showed that the phytic acid/silane hybrid coating could induce CaP-mineralized product deposition, which offered another protection for magnesium alloy.