| In order to improve the problems of the magnesium having bad corrosion resistance, the titanium having bad bioactivity and they all with low bone repair speeding etc, this article used the ultrasonic auxiliary micro-arc oxidation new technology and according to the security value of human bone essential elements, added proper AgNO3, La(NO3)3 , NaF and Na2SiO3 additives into the basis electrolyte system with the Ca and P elements respectively, Prepared the porous new biocoatings materials having wear, corrosion and antibacterial activities for bone repair by carrying on biological modification processing on the magnesium and titanium surface.The micro-morphology and organization structure of coating were analyzed by SEM, EDAX, AFM, XRD, HRTEM. The formation mechanism of the ultrasonic auxiliary micro-arc oxidation coating was studied. The coating thickness, surface porosity, bonding strength, the friction and wear and corrosion resistance in the SBF, and the antibacterial activity were tested.Results showed that the biocoating prepared by ultrasonic auxiliary micro-arc oxidation technology is composed of the compact layer and the surface porous layer, the thickness distribution uniformity, the bonding strength and the deposition quantity of the positive ions of the micro-arc oxidation coating are enhanced by introduction of the ultrasonic technology; the coating formation mechanism is growing toward the substrate's interior in early stage, then growing toward the substrate's exterior, the mechanism of the element enters the coating mainly are the proliferation and the electrophoresis; The surface elements deposited quantity and type, the coating thickness and porosity are enhanced by the addition of AgNO3 , La(NO3)3, NaF and Na2SiO3 additives. The coating thickness of the magnesium and the titanium based new biocoatings are respectively about 16um~30um, 76um~90um, the porosity are respectively about 26%, 23%, and are respectively consist with three dimensional island structure's crystal states particles of 10nm~67nm particle size's nanometer level periclase type MgO and of 2.5nm~15nm particle size's nanometer level anatase and rutile type TiO2. And the magnesium based silver-carrying biocoating is also have the crystals of the Ag2O with antibacterial function and the Ca9MgNa(PO4)7 with biological activity, and the titanium based silver-carrying biocoating is also have the crystals of the Ag2O, which could improve the coating antibacterial performance effectively and other special functions.Comparing with the single calcium and phosphorus biocoating, when the additives contents changing, the bonding strength of the magnesium based fluorine-carrying coating is increased by 3.47MPa～10.00MPa, the titanium based silver-carrying, lanthanum-carrying and silicon-carrying are increased by 1.97MPa～16.49MPa, 2.93MPa～14.00MPa and 6.71MPa～ 8.92MPa from the tensile test, which manifested the substrate has good bonding strength with the coating; The friction coefficient of the magnesium based silver-carrying, fluorine-carrying and silicon-carrying are decreased about by 0.18~0.32, 0.17~0.35 and 0.19~0.31, the titanium based silver-carrying, lanthanum-carrying and silicon-carrying coating are decreased about by 0.16~0.48,0.41~0.52 and 0.13~0.48 from the friction and wear test, the materials manifests the excellent antiwear ability, the friction and wear mechanisms of the new biocoatings in the SBF mainly are abrasive wear and adhesive wear; The corrosion potential of the magnesium based silver-carrying, fluorine-carrying and silicon-carrying in the SBF are increased by 11mV～102mV, 95mV～170mV and 18mV～138mV,the corrosion current density are decreased about by one to two order of magnitude, the corrosion potential of the titanium based silver-carrying, lanthanum-carrying and silicon-carrying are increased by 15mV～47mV, 94mV～163mV and 57mV～136mV, the corrosion current density are decreased about by one to two order of magnitude from the electrochemical corrosion test, the materials manifests excellent corrosion resistance, and the corrosion mechanism of the new biocoatings in the SBF is pitting corrosion; The antibacterial rate of the magnesium based silver-carrying, fluorine-carrying and the titanium based silver-carrying, lanthanum-carrying coating are 90%~96%, 61%~76%, 61%~92% and 50%~68% respectively, this kind of materials could be to play the function of antisepsis and anti-inflammation function on bone tissue repairing process. |
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