The Medical Implant Of Mg-6% Zn / (beta-tcp) Composites And Their Associated Performance

Due to their similar elastic modulus to bone, excellent biocompatibility and mechanical properties and corrosion resistance in biological environment, they also can degradation in the human body and avoid the secondary damage to the patient, so magnesium alloys have been widely studied and start apply on the clinical.According to exploitation status quo existing flaws of magnesium alloys for surgical implants, considering the design principles and preparation technology, new magnesium alloys Mg-6%Zn and Mg-6%Zn/(β-TCP) for surgical implants is designed and studied, then use OM, XRD, SEM, weight loss, hydrogen experiments and electrochemical polarization method to study their microstructure, mechanical properties and the corrosion resistance in Ringer solution which has the similar component of the human body fluid. The concrete contents and results are shown as the follows:According to characteristics of each kind of magnesium alloy, the design principles of the alloy, Zn andβ-TCP powder are selected as intensification elements, with excellent corrosion resistance and outstanding biocompatibility, at the same time.Based on the effect of Zn on strength of the magnesium alloy, selected the Mg-Zn alloys which contain 6%(wt%) Zn, and then addβ-TCP powder, use hot-pressing method to prepare Mg-6%Zn/(β-TCP) alloy.β-TCP particles unevenly distributed in the Mg-6%Zn alloys with different sizes, and there is no new phase generate with the addition of P-TCP, such characteristics are conducive to ensuring the compatibility of biological materials.With the increase ofβ-TCP content, the hardness and elastic modulus of the alloy are raised, but the relative density and compression strength are decreased. Compressive strength, respectively:345MPa,339MPa,284MPa, elastic modulus:21GPa, 24GPa,36GPa, and the elastic modulus is very close to human bone 3～20GPa.The corrosion rates show that:Mg-6%Zn-10%βP-TCP alloy has the best corrosion resistance, the weight loss corrosion rate is 0.35～4mg/cm2·d, experimental results of hydrogen evolution is 4.7mg/cm2-d, electrochemical polarization results is 1.38mg/cm2·d, the corrosion rate is much lower than the Mg-6%Zn alloy not addedβ-TCP, which has the corrosion rate of 25～45mg/cm2·d. In addition the white precipitate products generated by magnesium alloy's corrosion is mainly composed of Mg (OH)2,during the alloy corrosion in the Ringer solution, CaCO3 detected in the alloy surface, which has excellent biocompatibility and low solubility, it also can serve as a surface protection layer to the new type of medical magnesium alloy implant materials, the formation of CaCO3 can improve the corrosion resistance of the alloy.As a new biomedical implant magnesium alloy, Mg-6%Zn-10%β-TCP is in good accordance with the requirements of the alloy designing principles, has to meet the requirements of the mechanical properties and good corrosion resistance, so the application outlook is promising.