Synthesis of biphasic calcium phosphate containing nanostructured films by micro arc oxidation on magnesium alloy

• Synthesis of innovative biphasic calcium phosphate containing nanostructured films via micro arc oxidation.
• Nanocomposite film has lower degradation rate than pure MAO film.
• Greater apatite forming ability for nanocomposite coating compared with pure MAO film is obtained.

The present research reports the synthesis of an innovative nanostructured composite film containing biphasic calcium phosphate (BCP) by the micro arc oxidation (MAO) method on AZ31 magnesium alloy. Nanometric structure of the used hydroxyapatite powder and the coatings were characterized by means of transmission and field-emission scanning electron microscope, respectively. Electrochemical behaviors of the pure MAO and nanocomposite films were also evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization tests in simulated body fluid (SBF) environment. The results showed higher corrosion resistance of nanocomposite film compared to pure MAO coating, which was related to the blocking feature of the nanoparticles from the diffusing of the corrosive medium through the substrate. In addition, by immersing the specimens in simulated body fluid, greater apatite forming ability of the nanocomposite coating was proved.