Conversion Coating on AZ91D Magnesium Alloy in Stannate Solution

The surface morphology and corrosion resistance of the stannate conversion coating on magnesium alloy AZ91D was investigated using SEM,XRD and salt immersion test.The stannate solution contained proper Na2SnO3,NaOH,CH3COONa,and additives.The conversion coating was composed of α phase Mg,β phase Mg and MgSnO3·3H2O.The coating was silvery white and uniform,consisted of hemispherical particles,and could provide effective protection for the magnesium alloy AZ91D.