To improve the corrosion resistance of magnesium alloys

corrosion inhibition of sodium benzoate(SB)for AM60 magnesium alloy in 3.5%NaCl solution and influence of temperature on inhibition efficiency were investigated with electrochemical impedance spectroscopy(EIS)

polarization curves and immersion.Surface morphology of magnesium alloy after corroding with different concentrations of SB at different temperatures was observed with scanning electron microscope(SEM)

and corrosion inhibition mechanism of SB was analyzed.SB reduced obviously the corrosion rate of AM60 magnesium alloy in 3.5% NaCl solution

and inhibition efficiency was more than 75% at 0.5 mol·L-1 SB.Physical adsorption of SB occurred on AM60 magnesium alloy

and it belonged to an exothermic

entropy increase and spontaneous process.A multi-molecular adsorption layer was formed on the magnesium alloy surface to prevent the magnesium alloy from contacting corrosive solution.The activation energy for the corrosive reaction increased with increasing SB concentration

resulting in increasing inhibition efficiency.When SB concentration was up to 0.7 mol·L-1

inhibition efficiency did not increase

because intermolecular repulsion dominated with increasing SB concentrations.Moreover

inhibition efficiency did not increase when temperature changed from 25℃ to 70℃.