医用钛合金表面连通多孔层的阳极氧化制备及性能研究

发布时间：2018-01-24 21:05

本文关键词： NiTi合金阳极氧化纳米多孔氧化钛耐腐蚀性　出处：《上海交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：在生物医用材料领域,纯钛及钛合金被普遍认为是最具有前途的候选材料。其中,纯钛具有优异的生物相容性和耐腐蚀性,但这种金属的强度及耐磨性相比不锈钢等医用合金较差。近等原子比NiTi合金相比纯钛有着优良的机械强度和耐磨性,并且具有独特的形状记忆效应和超弹性,其杨氏弹性模量在所有已知医用合金中为最低、最贴近人体骨骼弹性模量值。然而医用NiTi合金中的Ni元素具有严重的细胞毒性和致癌性,这一缺陷严格限制了NiTi形状记忆合金在医学领域的应用。针对以上情况,人们对钛及钛合金进行了各种表面改性研究,通过调整材料表面的微观结构和化学组成来实现进一步提高生物活性和减少有毒元素释放(镍钛合金)的目标。本文研究了在医用纯钛和镍钛形状记忆合金表面获得连通多孔氧化层的阳极氧化工艺,通过扫描电子显微镜、X射线衍射仪、X射线光电子能谱仪等系统研究了表面改性对试样表面组织结构和成分的影响,并通过电化学循环极化测试和SBF模拟体液浸泡测试评价了阳极氧化表面改性后NiTi形状记忆合金的耐腐蚀性能,研究表明:在含有F-的乙二醇基溶液中对NiTi形状记忆合金进行改性后,样品表面生成了较规则的连通多孔氧化层,孔层厚度达若干微米,且氧化层Ni含量较基体明显降低。电化学测试和SBF模拟体液测试结果显示,经阳极氧化表面改性的Ni Ti合金表面耐腐性提高,Ni元素在模拟体液环境中的溶出量受到有效抑制。采用类似的阳极氧化工艺对纯钛进行不同的阳极氧化处理后,试样表面均生成排列整齐的锐钛矿相纳米管阵列氧化层。综上所述,一定的阳极氧化表面改性处理能在NiTi形状记忆合金表面获得具有低Ni含量和连通多孔结构的氧化保护层,可以有效改善Ni Ti合金的生物活性;而纯钛表面经类似阳极氧化处理后则一般获得纳米管阵列结构。同时本文还研究了非等原子比镍钛合金的阳极氧化行为,藉此探讨了连通多孔结构的形成机制。
[Abstract]:In the field of biomedical materials, pure titanium and titanium alloys are generally considered as the most promising candidate materials. Among them, pure titanium has excellent biocompatibility and corrosion resistance. However, the strength and wear resistance of this metal are worse than those of medical alloys such as stainless steel. The near isatomic NiTi alloy has better mechanical strength and wear resistance than pure titanium. It has unique shape memory effect and superelasticity, and its Young's modulus of elasticity is the lowest of all known medical alloys. However, the Ni element in medical NiTi alloy has serious cytotoxicity and carcinogenicity. This defect severely limits the application of NiTi shape memory alloys in the medical field. In view of the above situation, various surface modification studies have been carried out on titanium and titanium alloys. Further enhancement of biological activity and reduction of toxic element release by adjusting the microstructure and chemical composition of the surface of the material (Ni-Ti alloy). In this paper, the anodic oxidation process of porous oxide layer on the surface of medical pure titanium and nickel titanium shape memory alloy was studied. The effects of surface modification on the surface structure and composition of the samples were studied by means of scanning electron microscope (SEM) and X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of NiTi shape memory alloy modified by anodized surface was evaluated by electrochemical cyclic polarization test and SBF simulated body fluid immersion test. The results showed that after modification of NiTi shape memory alloy in ethylene glycol solution containing F-, a regular porous oxide layer was formed on the surface of the sample, and the pore layer thickness was several microns. The results of electrochemical test and SBF simulated body fluid test showed that the corrosion resistance of Ni-Ti alloy modified by anodic oxidation was improved. The dissolution of Ni element in simulated humoral environment was effectively inhibited. Different anodic oxidation treatments were used to treat pure titanium with similar anodic oxidation process. The anatase nanotube array oxide layer was formed on the surface of the sample. A certain amount of anodized surface modification can obtain a protective layer with low Ni content and porous structure on the surface of NiTi shape memory alloy, which can effectively improve the biological activity of NiTi alloy. On the other hand, nanotube arrays were obtained by anodizing of pure titanium surface, and the anodic oxidation behavior of non-equiatomic Ni-Ti alloy was also studied, and the formation mechanism of connected porous structure was discussed.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG146.23

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