Preparation And Application Basic Research Of Apatite Coating Magnesium-based Biomaterials

Medical metal materials with high strength, good toughness and high resistance to bending fatigue strength, easy processing molding and other fine features, and showed good mechanical properties in the replacement of biological bone tissue. The elastic modulus of magnesium is closer to biological bone, and magnesium ions are required for living organisms, is an ideal bone substitute material. Apatite has excellent biocompatibility and biological activity, its chemical composition and structure is similar to human bone. Mg-based apatite coating bio-composites material, can make full use of apatite and magnesium metal as a great superiority of biological materials, and can effectively resolve the magnesium's corrosion in vivo by body fluids. The bio-composites material can be expected to be the ideal material of repairing injuried biological hard tissue or replace in the future. This study based on the domestic and foreign researches on the application of magnesium alloys in biological materials, conducting the preparation and application basic research of Mg-based biomaterials. Results for achieving industrial applications of Mg-based apatite coating bio-composites material, improving the quality of human life, protecting human health, saving lives and creating significant social and economic benefits have significant social and economic benefits.In this thesis, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and other test methods were used to test the corrose dynamics and mechanism of magnesium in Simulated Body Fluid. The results showed that: magnesium in SBF solution, mainly occured hydrogen corrosion, corrosion products were mainly Mg(OH)₂, the corrosion rate of the magnesium in SBF solution was inversely proportional to the immersion time.Based on the corrosion properties of magnesium metal in SBF solution, to improve the magnesium's surface environment of deposite apatite coating and the corrosion resistance of magnesium sample, pretreatment of acid-base and activation methods were carried out to magnesium sample, and by optical microscope and scanning electron microscopy (SEM), observed the organization status of magnesium surfaces after pretreatment to determine the best substrate pretreatment parameters, the results show that in the acid-base pretreatment, the best time for pickling was 400⁴80s, alkaline washing time was 5 15 minites, the activation time was 30min.Prepared apatite coating magnesium biological materials by biomimetic deposi- tion. Prepared three different biomimetic solution, by measured the Mg²⁺, Ca²⁺ concentration in the deposition solution and pH value changes of deposition solution, combined with X-ray diffraction (XRD), electron spectroscopy analysis (EDS) and scanning electron microscopy (SEM) and other test methods analyzed the phase of deposition coating on sample surface and sediments in the deposition solution. The results showed that: The coating growth patterns were similar in three different biomimetic liquids, were all on the DCPD matrix growthing in dot and columnar growth pattern, suggested that after pre-calcification treatment, deposition coating composition tends to change apatite; Calcium ions were forming calcium phosphate salt precipitated from the bionic solution, the precipitation of calcium phosphate salt had a certain relationship with the corrosion rate of magnesium in the deposition solution,and has little with the concentration level of magnesium ions; Fluoride element was benefit to the precipitation of calcium phosphate salts; Biomimetic deposition of apatite on pure magnesium, fluorapatite coatings more easily deposited than hydroxyapatite, but the coating compositions have more Mg (OH)₂ still.