医用钛及钛合金表面阳极氧化多孔修饰及其性能的研究

发布时间：2018-01-28 23:06

本文关键词： 医用金属钛合金阳极氧化纳米多孔结构抗菌　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：钛及钛合金由于其优异的力学性能和良好的生物相容性,在生物医用材料领域具有广泛的应用。然而研究者经过长期临床应用与研究发现,现有的钛植入体仍然有许多亟待解决的问题。例如植入体与骨组织之间的弹性模量不匹配造成骨的吸收及植入体的松动,骨组织整合再生能力差,植入后感染等问题。通过对钛金属材料进行表面改性或采用模量较低的β型合金,可以有效的提高植入体材料的生物力学匹配性,改善生物相容性及生物活性,降低植入后细菌感染发炎的几率等问题。本论文采用电化学阳极氧化技术对钛进行了表面改性,制备得到了具有微纳尺度的三维贯通多孔结构的二氧化钛氧化层,并在此基础上于氧化层表面进一步构筑了一层含有纳米银／磷酸八钙的复合涂层,对改性后材料表面及涂层的微观形貌、物相组成、元素组分进行了检测和分析,对不同结构的氧化层生成机理进行了阐明,并对材料进行了体外生物学评价。同时采用阳极氧化技术对具有β相的钛铌合金表面改性,制备得到了纳米管阵列,并对氧化层的结构及性能进行了系统的研究和表征,探索了铌元素和氧化电压对表面改性纳米管阵列结构和表面性能的影响。本文的研究内容及结果具体包括以下三个方面：(1)通过阳极氧化法,在钛金属表面构筑了一层具有三维贯通多孔结构的氧化层,孔径大小可以通过电流密度等实验参数进行调控,孔径分布为30～200nm。三维多孔氧化层的形成与反应时间、电解质组分和电流密度密切相关。相比于类似实验条件下制备得到的纳米管阵列氧化层,具有三维贯通多孔结构氧化层的材料具有更好的力学性能如硬度、模量以及更强的界面结合力,而且具有更好的耐腐蚀性能。此外体外生物学评价显示,该氧化层有利于成骨细胞的黏附与增值,从而在生物医用方面显示了潜在的应用价值。(2)在金属钛表面进行三维贯通多孔修饰的基础上,利用光还原和仿生矿化技术相结合的方法进一步在材料表面构筑了一层纳米银／磷酸八钙复合涂层。该涂层中银以单质的形式存在,其含量可控,分布均匀。在表面构筑复合涂层后材料粗糙度进一步增加,并显示出超亲水性。此外,实验结果显示,该涂层能够实现银的持久缓释,对大肠杆菌和金黄色葡萄球菌均表现出了很好的抗菌活性,其抗菌率可分别达到93%和87%以上。(3)通过阳极氧化法在不同铌含量的钛铌合金表面制备得到了纳米管阵列。并对纳米管阵列生长的影响因素进行了系统研究。研究发现合金中的铌禽量的增加不改变表面纳米管阵列形貌。氧化电压的增大,能够增大纳米管阵列的管径和长度。在对合金表面纳米管阵列修饰后,材料的亲水性变得非常优异。且这种亲水性与表面纳米管阵列尺寸的密切相关,管径越小,亲水性越好。对材料进行热处理会使其表面亲水性变差。
[Abstract]:Titanium and titanium alloys have been widely used in biomedical materials due to their excellent mechanical properties and good biocompatibility. The existing titanium implants still have many problems to be solved, such as the mismatch of elastic modulus between the implants and bone tissues, resulting in bone resorption and loosening of implants, and poor ability of bone tissue integration and regeneration. Problems such as infection after implantation. Through surface modification of titanium metal materials or the use of 尾-type alloys with lower modulus, the biomechanical matching, biocompatibility and bioactivity of the implants can be improved effectively. In order to reduce the incidence of bacterial infection and inflammation after implantation, the surface modification of titanium was carried out by electrochemical anodization. Three-dimensional porous TIO _ 2 oxide layer with micro-nano scale was prepared, and a composite coating containing nano-silver / octadecalcium phosphate was further constructed on the surface of the oxide layer. The microstructure, phase composition and elemental composition of the modified surface and coating were examined and analyzed, and the formation mechanism of the oxide layer with different structures was clarified. At the same time, the surface of Ti-Niobium alloy with 尾 phase was modified by anodizing technology, and nanotube arrays were prepared. The structure and properties of the oxide layer were systematically studied and characterized. The effects of niobium and oxidation voltage on the structure and surface properties of surface modified nanotube arrays were investigated. An oxide layer with three dimensional perforated porous structure was constructed on the surface of titanium metal. The pore size can be controlled by experimental parameters such as current density. The pore size distribution is 30 ~ 200 nm. The formation of three-dimensional porous oxide layer is closely related to reaction time, electrolyte composition and current density, compared with the prepared nanotube array oxide layer under similar experimental conditions. The materials with three dimensional penetrating porous structure have better mechanical properties such as hardness, modulus and interfacial adhesion, as well as better corrosion resistance. In addition, biological evaluation in vitro shows that the material has better mechanical properties such as hardness, modulus and interfacial adhesion. The oxide layer is conducive to the adhesion and proliferation of osteoblasts, which shows potential application value in biomedical applications. 2) on the basis of three-dimensional porous modification on the surface of titanium metal. A nano-silver / octadecalcium phosphate composite coating was further constructed on the material surface by combining photoreduction and biomimetic mineralization technology. The silver in the coating exists in the form of a single substance and its content is controllable. After the composite coating was constructed on the surface, the roughness was further increased and the superhydrophilicity was shown. In addition, the experimental results showed that the coating could realize the sustained release of silver. It showed good antibacterial activity against Escherichia coli and Staphylococcus aureus. The antimicrobial rate was 93% and 87%, respectively. Nanotube arrays were prepared on the surface of titanium and niobium alloys with different niobium content by anodizing method. The factors affecting the growth of nanotube arrays were systematically studied. It was found that the increase of niobium content in the alloy did not change. Morphology of surface nanotubes array and increase of oxidation voltage. It can increase the diameter and length of nanotube arrays. The hydrophilicity of the materials becomes very good after the modification of nanotube arrays on the alloy surface, and this hydrophilicity is closely related to the size of surface nanotubes arrays. The smaller the diameter, the better the hydrophilicity. Heat treatment of the material will make its surface hydrophilicity worse.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TG174.4;R318.08

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