Preparation Of Apatite Coating On Surface Of Magnesium Via Biomimetic Synthesizing

Biomedical metallic materials possess fine mechanics properties which are used to restore and replace the hard tissue of human bodies.But the bad resistance to erosion and biocompatibility make the metallic materials away from the ideal substituted material.The module of elasticity of Mg is close to the bone of human,and the Mg ion is needed to the body.But the the low resistance to erosion makes the Mg substrate destroyed badly. HA is the main component of bone and teeth of human body,which can form a strong bond with the neighboring bone after implanted in the human body,but the brittleness of the ceramic limits its use.Attempts to prepare a bone-like apatite-metal composite have been made using a biomimetic process in which the metal surface is modified with functional groups effective in inducing apatite nucleation.-OH, -SiOH, and carboxyl or carboxylate groups have been used as the functional groups.In the present study, we activating the magnesium matrix with acid and dilute alkali solution and EDTA firstly,Ca²⁺ was induced onto the surface of magnesium by immersing it into the CaCl₂ solution; and then the specimen was dipped in phosphate ion solution to deposit apatite nuclei onto its surface. Then the specimens were immersed in SBF and metastable calcium phosphate solution (CP solution) respectively to form a layer on its surface.The coating formed on the magnesium is characterized by X-ray diffraction (XRD) and scanning electron microscopy(SEM).The results indicate that : when soaked in CP solution for 6d, an HA layer composed of well-grown flake-like crystals is formed on the surface of the magnesium.