The Study Of Biocompatible Porous Magnesium Processing, Property And Surface Modification

Porous magnesium with the porosity of 20-55% were fabricated by means of powder metallurgy method. The effects of the porosity on the Young's modulus, strength and average plateau stress were investigated by compressive tests. Results indicate that the porosity and pore size of porous magnesium can be controlled by spacer materials volume and size. The Young's modulus, the collapse stress, the average plateau stress and the bend intensity all decrease with the increase of porosity. The porous material has exceptional characteristics. The mechanical properties of the porous magnesium are in a range of those of cancellous bone. Therefore, the porous magnesium can be regard as one of promising scaffold materials for embedded application.The surface modification on porous magnesium was carried out to its corrosion resistance in simulated body (SBF) solution. Porous magnesium specimens were first treated in supersaturated NaHCO₃ — MgCO₃ mixed solutions (SNSM) at room temperature, and then heat-treated at 773 K for 10 h;finally, the corrosion resistance of the samples was tested in SBF solution. The X-ray diffraction (XRD) analysis shows that the coatings obtained on the samples after being treated in SNSM solution is mainly composed of MgCO₃.3H₂O. More important, Energy diffraction analysis shows a magnesium oxide layer is formed after heat treatment. It can be concluded that the coating obtained through alkali and heat treatment could effectively protect porous magnesium from corrosion in the simulated biological environment.The porous magnesium with different porosity was modified by alkali-heat-treatment and the samples were compared after soaked in the SBF solution. The result shows the resistance corrosion ability of the porous magnesium samples, without treatment or only by alkali-treatment, get worse and the PH of the SBF solution changes conspicuously. The porous magnesium samples have not been corroded after alkali-heat-treatment and the PH of the SBF solution changes unconspicuously. Only by alkali-treatment cannot improve the resistance ability of porous magnesium in the SBF solution, but the resistance ability of porous magnesium at any porosity improve greatly in the SBF solution.