The Studies On The Preparation And Biocompatibility Of Porous Ti-Ta Alloy

In this paper,Ti-Ta alloys containing 30 wt%and 40 wt%of tantalum were selected as the research materials?the two materials were denoted by 30Ta and 40Ta,respectively?.In the surface of materials,a tantalum-rich porous metal layer were prepared though removing or reducing Ti element by the de-alloying process.This method can reduce the cost of materials and keep materials with tantalum metal good bone conduction and long-term tissue compatibility.We used the method of chemical dealloying to prepare surface porous Ti-Ta alloy materials which have ideal porous structure and excellent performance and to explore the effect of process parameters such as composition of precursor,the composition and concentration of etchant and corrosion time on the pore structure of the material.The related performance such as pore structure,wettability and corrosion resistance of the prepared materials were characterized.The mechanism of pore evolution in the process of chemical de-alloying was studied in this paper.The effects of porous Ti-Ta alloy with different compositions on the proliferation,differentiation and osteogenic ability of the rat bone marrow mesenchymal stem cell proliferation.Specific research results are as follows:?1?For the Ti-Ta alloy system,the composition and microstructures of the precursor alloy have a decisive influence on the evolution of the pore morphology in the process of chemical dealloying,while the composition and concentration of the etchant and the time of the dealloying time play an unimportant role.?2?In the chemical de-alloying process,?-Ti and?-Ta solid solution with HF solution or HNO₃+HF mixed solution can form an original battery system,which led to form a large number of small original batteries in the precursor alloy surface.In the original battery system,?-Ti solid solutions can be dissolved and corroded as the anode,and?-Ta solid solutions as the cathode do not occur corrosion and dissolution.With the reaction continues,pore structure can form on the surface of the material.And the diffusion recombination of?-Ta phase did not occur during the process of pore evolution.This feature is different from the pore evolution mechanism of nano-porous materials prepared by chemical de-alloying process.?3?Etched in 0.5%HF solution for 12 hours at room temperature,the porous materials of 30Ta and 40Ta show less micro-fractures and ideal pore structures.And the porosities of these two porous materials were reached at 67.20%and 33.88%respectively.The tantalum content of the sample surface of these two porous materials was both improved highly.After the chemical dealloying treatment,the corrosion resistance of the two materials was not reduced significantly,and the wettability was better than its corresponding precursor alloy.?4?In the process of the experiment,partial peeling of the porous layer occurred on porous 30Ta material,which resulted from the change of the physical and chemical properties of the culture medium,showed some biotoxicity to the mesenchymal stem cells.Meanwhile,porous 40Ta material showed better biocompatibility,which plays a positive role in the process of proliferation and osteogenic differentiation of cells.