Design And Development Of Biomedical Titanium Alloy With Low Elastic Modulus

Medical titanium alloy was widely used in bone implants due to its low density and good machinability.However,there were some problems limiting the clinical application such as high elastic modulus,low biological activity,poor corrosion resistance and antibacterial property.In order to solve the problems,the main research direction was preparation and surface modification of titanium alloy.Titanium alloy was prepared by powder metallurgy,and nanotubes transition layer was prepared on alloy surface by anodizing.Finally,Ta coating and Ta Cu Zn coating samples were prepared on titanium alloy by plasma spraying technology.The phase composition,microstructure,mechanical properties and corrosion resistance were characterized by XRD,SEM,and universal testing machine.The result showed that Ti-27Nb-6Zr alloy had equiaxedβphase sintered at 1400℃for 2 h.The compressive strength and elastic modulus were 625 MPa and 52.15 GPa,respectively.On the basis of Ti-27Nb-6Zr alloy,Ti-27Nb-6Zr-5Mo alloy sintered at1400℃for 2 h had uniform ellipsoidalβphase.The compressive strength was increased to 760 MPa,and the elastic modulus was decreased to 42.24 GPa.Nanotubes with bore diameters of 30～40 nm were prepared on the surface of Ti-27Nb-6Zr-5Mo alloy in the solution of 0.9 wt%Na F and 1 mol/LH₃PO₄at voltage 25 V for 120 min.The thickness of Ta coating and Ta Cu Zn composite coatings that were prepared by plasma spraying were about 90μm and 70μm,respectively.Compared with the Ti-27Nb-6Zr-5Mo alloy,the surfaces of Ta coating and Ta Cu Zn coatings sample were covered with a white ellipsoid named Ca₅（PO₄）（OH）₃,showing excellent bioactivity.Electrochemical experiments showed that the self-corrosion voltage and polarization resistance of Ta coating were higher than those of other samples,which had better corrosion resistance.The cytotoxicity test showed that Ti-27Nb-6Zr-5Mo alloy,Ti-27Nb-6Zr-5Mo alloy with nanotubes,Ta coating had no cytotoxicity.Compared with other samples,the bacteriostasis circle was appeared around the Ta Cu Zn composite coatings,so the existence of Cu and Zn in the coatings had antimicrobial effect.Figure 42;Table 15;Reference 85.