退火对钛合金钽涂层力学及生物性能的影响OACSTPCD

The work aims to solve the problem that the modified coating of titanium alloy(TC4)is easily damaged due to the corrosion of body fluids and the friction between bones in bone implantation and replacement,which leads to the release of toxic metal ions,tissue and cell necrosis,thus causing the failure of implantation.The mechanical and biological properties of tantalum coating on the surface of TC4 can be improved by annealing process. In this study,TC4 titanium alloy with the size of ϕ 25×2 mm was selected as the matrix,which was ground to 2000#with sandpaper.Ta coating was deposited on the surface of TC4 matrix by magnetron sputtering technology,and annealed at different heat treatment temperature of 650,750 and 850℃for 5 h.The cross section morphology,composition distribution,phase structure,bonding strength,wear resistance,corrosion resistance and biocompatibility of Ta coating were tested and characterized by scanning electron microscope(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD)scratch instrument,multi-functional high temperature friction and wear testing machine,electrochemical workstation and biotoxicity test. The microstructure of the prepared Ta coating was relatively dense,and became denser at a certain annealing temperature without obvious micropores.The hardness value(16.68 GPa)and elastic modulus value(208.90 GPa)at the annealing temperature of 650℃showed the highest performance,which was due to the generation of strong β-Ta peak,improving the hardness value significantly.After annealing at 750℃,the coating had the maximum bond strength(20.82 N),the excellent corrosion resistance,the smallest fluctuation of the friction curve,the most stability and the lowest average coefficient of friction(COF)value.This was due to the mutual diffusion of elements between the coating and the matrix,which reduced the interfacial stress and promoted the increase of bond strength.This was beneficial to improving the density of the coating,reducing the microporous defects on the coating surface,hindering the corrosion solution through the coating path action,thus improving the corrosion resistance of the matrix.At the same time,it effectively prevented the large area of the coating from falling off,reduced the friction surface area,and improved the friction performance of the coating.The RGR of tantalum coating at 750℃and 850℃annealing temperature was>80%,showing good biocompatibility. In conclusion,the annealing process significantly improves the mechanical and biological properties of the coating.After annealing at different temperature,the microstructure of the coating is more compact and uniform,the hardness value and bond strength are higher,and the wear resistance,corrosion resistance and biocompatibility are better.