Nano-Mechanical Properties,Corrosion,Wear Behavior And Antibacterial Activity Of Medical Titanium Alloy

In recent years,titanium?Ti?and Ti alloys are widely used as medical biomaterials in human body due to their good biocompatibility and excellent mechanical properties.In order to further improve biocompatibility,new Ti alloys containing non-toxic elements zirconium?Zr?,tin?Sn?,molybdenum?Mo?and niobium?Nb?have attracted the attention of researchers.Zr is a good biocompatible element.Moreover,numerous properties of Zr,such as high mechanical properties,low density,and biocompatibility are similar to those of Ti because Zr and Ti belong to the same group.Therefore,Ti-Zr alloys have attracted widespread attention.In this paper,new binary alloys Ti-1Zr,Ti-2Zr and Ti-16Zr alloys were prepared.The nano-mechanical properties of the alloys were tested by nano-indentation hardness tester.The corrosion resistance of the alloys in artificial body fluids was studied by electrochemical method.The wear properties were investigated using friction and wear tester.After the alloy is implanted into the human body,it is easy to infect bacteria and make it unable to function normally.Therefore,the Cu/TiO₂ film is prepared on the surface of the alloy by anodizing and potentiostatic electrodeposition.The work and results of this paper are as follows:?1?The nano-mechanical properties of cpTi,Ti-1Zr alloy,Ti-2Zr alloy and Ti-16Zr alloy were investigated by nanoindentation test.Compared with Ti-Zr alloy,cpTi has strong resistance to external loads,high hardness and small plastic deformation.With the increase of Zr content,the hardness of Ti-Zr alloy increases,the ability to resist external loads increases,and the plastic deformation decreases.The elastic modulus of cpTi,Ti-1Zr alloy,Ti-2Zr alloy and Ti-16Zr alloy are 104.8 GPa,118.3 GPa,114.9 GPa and 115.6 GPa,respectively.?2?Using the potentiodynamic polarization curve and the impedance spectrum curve method to study the corrosion resistance of cpTi,Ti-1Zr alloy,Ti-2Zr alloy and Ti-16Zr alloy in simulated artificial body fluids.Ti-2Zr alloy shows highest corrosion potential and lowest corrosion current density in comparison with other alloys,while cpTi has the lowest corrosion potential and the highest corrosion current density.The corrosion resistance of all specimens can be listed in the following order:Ti-2Zr>Ti-1Zr>Ti-16Zr>cpTi.?3?The wear resistance of cpTi,Ti-1Zr alloy,Ti-2Zr alloy and Ti-16Zr alloy in simulated artificial body fluid were tested by friction and wear tester.The results show that all the samples exhibit a variety of wear mechanisms during the friction and wear process.The wear mechanisms in Ti-Zr alloy are abrasion,delamination,oxidation and adhesion,whereas in cp Ti these are adhesion,abrasion and oxidation.For Ti-Zr alloy,the wear volume decreases with the increase of Zr content.Similarly,the specific wear rate decreases with the increase of Zr content.Wear resistance of the specimens in the solution changes in the following order:cp Ti?Ti-16Zr>Ti-2Zr>Ti-1Zr.?4?The Cu/TiO₂ film on the surface of Ti-Zr alloy was prepared by anodizing and potentiostatic electrodeposition.The antibacterial properties of Cu/TiO₂ film were studied.In the process of preparing Cu/TiO₂ film,the effects of sample composition,deposition time and deposition voltage on the morphology of Cu/TiO₂ film were evaluated.The results show that a highly ordered nanotube layer was formed on Ti-Zr alloy by the anodization technique.The average diameter of the nanotubes is about 100 nm to 120 nm,and the wall thickness of the nanotubes is about 20 nm.In the process of potentiostatic electrodeposition of Cu,the composition of the sample,the deposition time and the deposition voltage all have an effect on the morphology of the Cu/TiO₂ film.The antibacterial properties of Cu/TiO₂ film were studied by plate counting method.It was found that Cu/TiO₂ film has certain antibacterial ability.The antibacterial effect of the sample on Staphylococcus aureus is better than that of Escherichia coli.