Influence of Electric Parameters on Growth of Hard Anodizing Film on 2024 Aluminum Alloy

Hard anodizing film was prepared on the surface of 2024 Al alloy. The morphology and phase composition of the anodizing film were analyzed by means of scanning electron microscopy and X-ray diffraction, and the effects of electric parameters (current density, pulse frequency, duty cycle and pulse amplitude) on the growth of the oxidation film were examined. Results show that, independent of the anodizing systems and electric parameters, the hard anodizing film tends to preferably grow towards the substrate but not outwards from the substrate, with the thickness of the layer growing towards the substrate being about 51%-64% of the total thickness of the anodizing film. However, the anodizing systems and electric parameters have no significant effects on the growth of the anodizing film, and varying electric parameters does not lead to change of amorphous structure of the anodizing film.