The synergistic inhibition effect of organic silicate and inorganic Zn salt on corrosion of Mg-10Gd-3Y magnesium alloy

The inhibition effects of organic sodium aminopropyltriethoxysilicate (APTS–Na) and inorganic zinc nitrate on the corrosion of Mg-10Gd-3Y magnesium alloy (GW103) in ASTM D1384-87 corrosive water are investigated by electrochemical techniques and immersion test. The results show that individual organic or inorganic inhibitor has low inhibition efficiency. However, when these organic and inorganic inhibitors are used together, a synergistic inhibition behavior is observed. The Mg alloy surfaces after immersion test were analyzed using scanning electron microscope (SEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). The surface in the inhibitor containing solution is found to be covered by a film composed of Mg(OH)2 and silicate. It is believed that the formation of this surface film is responsible for the synergistic inhibition effect of the organic and inorganic inhibitors.

► Zinc nitrate has low inhibition efficiency for Mg10Gd3Y0.5Zr Mg alloy.
► Sodium aminopropyltriethoxysilicate has low inhibition efficiency for the Mg alloy.
► These two inhibitors used together have high inhibition efficiency for the Mg alloy.
► These two inhibitors have a synergistic effect on the Mg alloy in corrosive water.