Effects of 0

1

2.0 g/L（NaPO3）6 in a Na2SiO3 electrolyte solution on the thickness

porosity on the surface of ZAlSi12Cu2Mg1 rate and phase constituent of ceramic coatings prepared by MAO have been observed.The results indicate that with increasing the（NaPO3）6 content from 0 to 12 g/L

the thickness of MAO coatings is increased gradually

and the porosity rate is decreased with（NaPO3）6 content increasing from 0 to 6.0 g/L while it is increased with（NaPO3）6 content more than 6.0 g/L.XRD analysis reveals that the ceramic coating oxidized in the electrolyte solution without（NaPO3）6 is composed of γ-Al2O3

α-Al2O3 and Al2SiO5

in which the intensity ofα-Al2O3 is equal toγ-Al2O3

while oxidized in the electrolyte solution with 6.0 g/L（NaPO3）6

it is no found that there exists Na+ or PO3-in the coatings

however

the intensity of α-Al2O3 is more than γ-Al2O3 distinctly

and the intensity of Al substrate is slightly decreased.