生物医用钛基复合材料的研究

【作者】 韩超；

【导师】 朱心昆；

【作者基本信息】 昆明理工大学 ， 材料学， 2012， 硕士

【摘要】 由于钛和钛合金具有良好的机械性能、生物相容性和耐蚀性,因而被广泛的应用于骨组织工程的承重支架。然而,固态的钛及钛合金要比人的骨骼坚硬得多,而且不能提供新的骨组织生长能力和血管形成的空间,这会导致植入管疏松以至最后的失败。据不完全统计,大约百分之二十到二十五接受骨科移植手术的患者都需要再做一次修正手术。解决这个问题的办法就是使植入骨骼的结构和机械性能与人身体上的骨骼相匹配。然而,当孔隙率增加到能够满足自然骨骼要求并且能够使新的骨组织生长和血管形成的时候,多孔纯钛的强度随着孔隙率的提高,迅速的降低,并且强度远低于自然骨骼。因此,增强钛及其合金的强度以保证提供合格的刚度,并且在使用多孔结构时拥有足够的强度就显得尤为重要了。高孔隙率的多孔纯钛在植入材料领域是很有发展前景的。由于具有低廉的价格及各向异性的特点,颗粒增强型金属基复合材料获得了越来越多的关注。提高金属及金属基多孔材料的强度可以通过基体增强相来实现。例如,将细小的陶瓷颗粒或者合金元素通过粉末冶金的方法加入到基体粉末中。增强相颗粒的大小、形状以及含量将影响材料的弹性模量、强度、断裂韧性和屈服强度。在本次研究中我们选择了SiO2/ZrO2/Nb2O5三种具有良好生物相容性的氧化物颗粒来制备钛基复合材料,以保证样品具有良好的生物相容性和机械性能。钛基复合材料采用粉末冶金的方法制备出来。我们通过X射线衍射分析、金相显微镜、扫描电子显微镜和机械性能测试研究了成分组成和烧结温度对钛基复合材料机械性能和生物相容性的影响。密度测试的结果表明,随着烧结温度的提高,材料的致密度均有所提高。机械性能测试的结果表明加入氧化物后,钛基复合材料的强度相对于纯钛均有了显著的提高,同时还保持了良好的塑性。加入量为2%SiO2并且烧结温度在1100℃的样品的屈服强度达到1566MPa并且极限应变也有15.96%。加入量为4%ZrO2并且烧结温度在1100℃的样品的屈服强度达到1280MPa并且极限应变也有24.13%。加入量为2%Nb2O5并且烧结温度在1100℃的样品的屈服强度达到1494MPa并且极限应变也有16.44%。生物相容性实验的结果表明此次研究的钛基复合材料均具有良好的生物相容性和细胞粘附性。类成骨细胞在钛基复合材料上的生长和繁殖情况均好于纯钛本课题证明了SiO2/ZrO2/Nb2O5颗粒增强型钛基复合材料在骨组织植入材料领域是一种很有发展前景的材料。更多还原

【Abstract】 Titanium and its alloys are widely used as load-bearing implants for bone tissue engineering due to their good mechanical properties, good biocompatibility and excellent corrosion resistance. However, titanium and its alloys in their solid forms are much stiffer than human bone and do not provide new bone tissue ingrowth abilities and vascularisation, leading to implant loosening and eventual failure. It is estimated that20-25%of patients having an orthopaedic implant will eventually require a secondary revision surgery. The solution is to match both the architecture and the mechanical properties of implants to those of nature bone. However, the strength of porous pure titanium deceases dramatically with the introduction of porosity and is lower than that of natural bone, when the porosity is increased sufficiently to match the stiffness of natural bone and enable new bone tissue ingrowth and vascularisation. Therefore, it is important to enhance the strength of titanium and its alloys to ensure appropriate stiffness, as well as adequate strength when it is used in a porous structure.Porous pure titanium (Ti) scaffold with high porosity is promising for use as implant materials. Particulate-reinforced metal composites have attracted extensive attention as a result of their relatively low costs and characteristic isotropic properties. The mechanical properties of metal and its foams can be improved by matrix reinforcement, e.g. adding fine ceramic particles or alloying elements in the base powder of the powder metallurgical route. The size, shape and volume fraction of the reinforcement affect the elastic modulus, strength, fracture toughness and compressive creep propertiesIn this study, biocompatible SiO2/ZrO2/Nb2O5particles are selected for fabricating the particulate-reinforced Ti composites to ensure its biocompatibility and mechanical property. The particulate-reinforced Ti composites are fabricated using powder metallurgy (P/M). The effects of composition and sintering temperature on the microstructure and properties of the Titanium-Based Composites were investigated by X-ray diffraction, optical microscope, scanning electron microscopy and mechanical properties tests. The relative density result showed that the relative density increased with increasing sintering temperature. The results indicate that the strengths of the composites are significantly higher than that of pure titanium. At the same time these composites preserved good elasticity. The sample added2%SiO2and sintered at1100℃exhibited a compressive strength of1566MPa and a ultimate strain of15.96%. The sample added4%ZrO2and sintered at1100℃exhibited a compressive strength of1280MPa and a ultimate strain of24.13%. The sample added2%Nb2O5and sintered at1100℃exhibited a compressive strength of1494MPa and a ultimate strain of16.44%. In vitro results reveal that the composite possesses excellent biocompatibility and cell adhesion. Osteoblast-like cells grew and spread better on the surfaces of the Ti/SiO2composites than pure Ti.This study demonstrates that the SiO2/ZrO2/Nb2O5particulate-reinforced Ti composite is a promising material for great potential use as an orthopedic implant material.更多还原