Formation of calcium phosphate coating on Mg-Zn-Ca alloy by micro-arc oxidation technique

Abstract

A porous bioceramic containing tricalcium phosphatein (TCP) coating was prepared by micro-arc oxidation (MAO) with different voltages. The degradability and bioactivity of the coatings were measured by immersion tests in the stimulated body fluid (SBF). The thickness, phase composition and morphology of the oxide coating were monitored with X-ray diffraction (XRD), fourier transform infrared spectrometer (FT–IR) and scanning electron microscopes (SEM) with energy energy-disperse spectrometer (EDS). The results show that the TCP-containing coating can be influenced by the increasing applied voltages through affecting the energy of sparking and the effect of electrical field. The MAO coatings have porous surface morphologies with uniform and compact micropores. The results of immersion tests confirm that the TCP-containing MAO coating has bioactivity and could protect Mg–4.75Zn–0.55Ca alloy from corrosion effectively.