【作者】 王军；

【导师】 阮建明；

【作者基本信息】 中南大学 ， 材料科学与工程， 2012， 硕士

【摘要】 金属铌具有优良的生物活性和生物相容性以及最低的生物毒性,近年来逐渐成为生物科学家们研究的热点。传统的金属生物材料由于比重大,弹性模量高,生物活性差等缺点,减弱了植入效果。因此设计和制造出具有优良的生物活性和生物力学相容性的多孔铌生物材料成为了科学家的研究热点。本论文采用有机泡沫浸渍法制备多孔铌生物材料。首先,配置不同浓度的聚乙烯醇溶液,采用不同型号的聚氨酯有机泡沫作为模板来制备具有不同浸渍量的多孔铌坯体,从而获得具有最佳孔隙率的多孔铌试样；其次,采用中频加热炉对多孔铌坯体进行烧结,通过设定不同的烧结温度、时间进行对比试验,优化多孔铌试样的力学性能,从而得到最佳的烧结参数；最后,利用流体静力学法测量多孔铌试样的孔隙度,采用电子万能试验机测试多孔铌试样的抗压强度和弹性模量,通过SEM、立式显微镜对多孔铌试样的孔隙形貌、微观组织结构、断口形貌以及碳氧元素含量及分布进行了分析和观察。研究结果表明：多孔铌试样的浸渍量随着聚乙烯醇(PVA)的浓度增加先增加后降低,而多孔铌试样的孔隙率则是先降低后增加,PVA最佳浓度为5%,对应的孔隙率为65.8%；多孔铌保留了泡沫的三维连通孔隙形貌,与松质骨相似,孔隙尺寸在300-500μm之间,材料表面凹凸不平,粗糙,在孔壁上还存在大量的微孔；多孔铌试样的压缩曲线分为三个阶段,存在一个应力平台；随着孔隙率的增加多孔铌试样的抗压强度逐渐降低,弹性模量也逐渐变小；烧结温度为1750℃时抗压强度具有最大为36.69MPa,弹性模量为0.817GPa之间,与人体骨小梁的力学性能相一致；随着烧结时间的增加力学性能也随之提高,烧结时间为2h时弹性模量和抗压强度达到最大值0.815GPa和36.6MPa；多孔铌试样的断面呈扇形花样,属于脆性断裂；碳氧在铌中形成间隙式固溶体,烧结后易在孔隙边缘处富集,所形成的脆性相使铌的塑形降低。更多还原

【Abstract】 Niobium, excellent bioactivity and biocompatibility and the lowest biological toxicity, in recent years has gradually become a research hotspot of biological scientists. However, the conventional metallic biomaterials implanted in the body have several inherent limitations such as, high density, relatively high modulus of elasticity and bad biological activity which weaken the implantation effect. How to design and manufacture porous niobium metallic biomaterials with both excellent bioactivity and biomechanical compatibility will be the research focus of scientists.In this paper the object was using the organic foam preparing the porosity porous niobium biological material by impregnation. First, using different types of organic polyurethane foam as a template to configured different concentrations of polyvinyl alcohol solution, prepare porous niobium green body with different impregnation amount, so as to obtain the best porosity porous niobium specimens. Second, using the medium frequency heating furnace sinter porous niobium green body by setting the sintering temperature, time, optimize the mechanical properties of porous niobium samples to get the best sintering parameters. Third, the porosity, compressive strength, elastic modulus, pore morphology, micro-organizational structure, section of the porous niobium sample and the contents and positions of oxygen and carbon were tested by hydrostatic, SEM and vertical microscope.The results show that:the amount of the impregnation of porous niobium sample is increased with the concentration of polyvinyl alcohol (PVA), at first the porosity of the porous niobium sample is reduced then increased; when the concentration of PVA is5%, we can get the best porosity at65.8%; the porous niobium has the three-dimensional connectivity of the organic foam pore structure morphology which is similar to cancellous bone,the pore size in the range of300-500μm, lots of micro-pore in the pore wall, the surface is very roughness;there are three stage of the compression stress-strain curve of porous niobium which has a stress flat; the elastic modulus gradually decreases with the porosity increased with the of the porous niobium sample; the max value of elastic modulus and compressive strength are0.815GPa and36.6MPa at the sintering temperature of2h; with the improvement of the sintering temperature, sintering neck diameterthe, mechanical properties were increased; the porous niobium’s fracture mode is brittle, fan-shaped fracture; carbon and oxygen impurity elements formed interstitial solid solution in niobium, enriched in the edge of the pore wall, which leads the niobium to brittleness.更多还原