Structure And Properties Of Modified Layers Used In Biology And Medical Applications By Micioarc Oxidation On Magnesium Alloy

Ceramic coatings containing Ca and P have been successfully formed on the surface of Mg alloys by Micro-arc oxidation (MAO) in this paper. The composition, chemical structure, surface characterization, frictional behaviors and corrosion resistance were studied by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), friction test and electrochemical measurement systematically.XPS survey spectra indicate that ceramic coatings containing Ca and P have been successfully formed on the surface of Mg alloys by MAO. As treating voltage increases from 400V to 500V, Ca/P first increases and then decreases. There is an optimal voltage (450V) corresponding to the highest ratio of Ca/P. Ca/P increase with the increase of concentration of the solution.AFM results show that the root-mean-square roughness (RMS) of Mg alloys increase remarkably after MAO treated. The RMS of MAO treated Mg alloys first increases and then decreases as increasing of the voltage. There is an optimal voltage (450V) corresponding to the lowest RMS.Friction tests are used to analyze the frictional behaviors of the MAO treated Mg alloys. The results show that the friction coefficients of Mg alloys after MAO treated have a lattle increase. The friction coefficients of the MAO treated Mg alloys in the same concentration of the solution at different voltages first decrease and then increase as increasing of the voltage. And the MAO treated Mg alloy at 450V has a lowest friction coefficient.The electrochemical test indicates that the corrosion resistance of Mg alloys is improved by MAO treated. Meanwhile, the voltage and the concentration of the solution have different influence on the corrosion resistance of MAO treated alloys. The corrosion potential of the MAO treated Mg alloys in the same concentration of the solution at different voltages first decrease and then increase as increasing of the voltage. The corrosion potential resistance of the MAO layers increases as the increasing of the concentration of the solution.