Study On The Preparation Of Magnesium Matrix Hydroxyapatite By Electrophretic Depossition

With excellent mechanical strength, low elastic modulus, biodegradable and biocompatibility properties, magnesium alloy was a kind of potential metallic biomaterials, which was suitable as artificial bone material. But the magnesium alloy have poor corrosion resistance performance and rapid degradation in body made it fail to meet the requirements of mechanical properties under the reserve service period, which hinders its clinical application. Hydroxyapatite( referred to as HA) is the main component of human bone tissue, which was an ideal surface coating material of artificial bone with good biocompatibility, bioactivity, strong corrosion resistance, no decomposition and bone induced ability properties. But HA was hard to be used as a bearing material because of its poor toughness and low strength. Therefore, the Hydroxyapatite was coated on Magnesium alloy to prepare Magnesium matrix hydroxyapatite biological composite material was an ideal artificial bone material which had appropriate degradation rate, excellent mechanical strength, low elastic modulus of magnesium alloy, good biocompatibility, bioactivity and bone induced ability of hydroxyapatite.In this paper, to prepare Hydroxyapatite biomaterial coatings on magnesium alloy, the anhydrous ethanol and nitric acid was used as the dispersion medium and electrolyte respectively to deposit HA coating on AZ31 B substrate by electrophoretic deposition method. The surface morphology, composition, mass and bonding strength of the coatings characterizations were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), electronic analytical balance and adhesive tensile tester, respectively. The effects of the aging time, the solid concentration and the deposition voltage on deposition coating were studied. To find the better electrophoretic deposition conditions by observed the effects of different parameters of electrophoretic deposition process on the surface morphology and performance of coating. And the Animal experiment and SBF immersion experiment were selected separately to test the biocompatibility and bioactivity. Also the corrosion resistance ability of Magnesium Matrix Hydroxyapatite Material was verified.The experimental results show that: the HA coating was deposited on the cathode Magnesium alloy substrate homogeneously. Suspension concentration of 0.02 kg/L, aging time of 10 days and electrophoretic deposition voltages of 60 V were the better electrophoretic deposition process parameters. The moderate thickness, weight and performance of HA coating could be obtained at this parameters condition. The animal experiments found that the implant composite material was not degraded, which around tissue appeared tissue hyperplasia and new blood vessels, but no obvious tissue inflammation, no infiltrating inflammatory cells such as multinuclear giant cells and neutrophils cells. The SBF soaking experiments results show that a layer Bone-Like Apatite was found on its surface after Magnesium Matrix Hydroxyapatite Material soaked in SBF solution. All results showed that Magnesium matrix hydroxyapatite biological composite material have no cytotoxicity, induction bone formation, good biocompatibility and bioactivity.