Study of the corrosion inhibition effect of sodium silicate on AZ91D magnesium alloy

The poor corrosion resistance of magnesium alloys is a major impediment to their applications in many fields. In this paper, sodium silicate as a corrosion inhibitor is studied on the inhibition effect of AZ91D magnesium alloy. From the results of the corrosion tests, sodium silicate could effectively improve the corrosion resistance of alloy at the optimum concentration 10 mmol/L, while the pH value range from 10.5 to 12.5 is preferable. The corrosion inhibition mechanism of the protective layers is also discussed. These results can provide a guide for the protection of magnesium alloy in the cooling water systems, etc.

Research highlights
► Sodium silicate can improve the corrosion resistance of magnesium alloy.
► Optimum concentration of sodium silicate is 10 mmol/L.
► The pH value range from 10.5 to 12.5 is preferable.
► Transparent silicate coating enables good corrosion resistance.