华 中 科 技 大 学 硕 士 学 位 论 文 I摘摘 要要 钛及钛合金因其良好的综合力学性能、耐蚀性和优异的生物相容性正受到广泛关注但是，金属钛材在生理环境下本身是生物惰性材料，植入体内后被一层包囊性纤维膜所包绕，难于和组织形成牢固的结合微弧氧化是一种在钛及钛合金表面制备具有生物活性多孔陶瓷膜的新技术，在钛合金的仿生表面改性领域具有潜在的应用前景本文采用微弧氧化和碱热处理复合的方法，在纯钛表面制备了含 Ca 和 P的复合生物活性陶瓷膜，经模拟体液浸泡获得了具有纳米网状结构的羟基磷灰石利用 SEM 、XRD、FT-IR、EDX、电化学测试及拉伸试验等分析测试手段研究了膜层的形貌、成分和物相组成、耐蚀性及膜层结合强度，并探讨了生物陶瓷膜及模拟体液诱导羟基磷灰石的形成机理 纯钛在含钙和磷的电解液中微弧氧化处理后，其表面原位生成多孔的氧化物陶瓷膜，氧化膜的外层为孔径较大的多孔层，部分孔洞有相互连通的现象；内层较致密，含有少量直径较小的孔洞膜层和基体之间没有明显的界面，呈锯齿状冶金结合纯钛微弧氧化膜主要由锐钛矿型 TiO2和金红石型 TiO2组成，膜层中含有 Ca 和P 元素，Ca 和 P 的含量沿膜层的截面由外向内逐渐降低，呈梯度变化，Ca 含量降低幅度大于 P 元素，Ca/P 摩尔比沿膜层截面由外向内逐渐减小。
脉冲电源的正电压是影响微弧氧化膜结构的主要参数随着电压的升高，氧化膜层表面孔洞的数量减少，孔径增大，表面粗糙度增加，膜层的结合强度降低当恒压电压为 300V 时 MAO 膜表层的 Ca/P 为 1.77，接近人体骨骼的 Ca/P 比电化学测试结果表明，微弧氧化使纯钛在模拟体液中的自腐蚀电位由-0.4767V 提高到-0.3189V， 说明微弧氧化可以显著提高纯钛在模拟体液中的耐蚀能力 优化后的微弧氧化工艺参数为：正压 300V，负压 30V，频率 600Hz，处理时间 5min，占空比 0.2 微弧氧化膜经碱热处理后，表面生成了由 CaTiO3和 Ca2P2O7组成的纳米棒与MAO 膜相比，锐钛矿型 TiO2的量减少，而金红石型 TiO2量略有增加；膜层的孔洞尺寸减小、孔隙率降低由于热处理过程中产生的裂纹和疏松使膜层的结合强度有所降低碱热处理后的膜层经 3 天的模拟体液浸泡，膜层表面出现了一些团絮状粒华 中 科 技 大 学 硕 士 学 位 论 文 II子，这些小粒子出现在微孔孔口和裂纹附近；浸泡 7 天后，膜层表面覆盖了一层球形羟基磷灰石（HA） ；浸泡 14 天后，膜层表面沉积的羟基磷灰石层厚度增加，表面凸起增多，形成许多胞状物。
在高倍（40000×）下观察，发现单个胞状物是由不规则的纳米环彼此相连呈网络状排列构成，具有典型的生理组装特性 关键词：关键词：钛；微弧氧化；碱热处理；膜层；模拟体液；羟基磷灰石 华 中 科 技 大 学 硕 士 学 位 论 文 IIIAbstract Titanium and its alloys have attracted attention as important biomaterials due to their good comprehensive mechanical properties, corrosion resistance and the excellent biocompatibility. However, Ti and its alloys are bioinert materials in a physiological environment, in which implants would be surrounded by cystic fibrosis. It is difficult to form a fast joint with tissues. Microarc oxidation (MAO) is a novel technique to form porous ceramic coatings with good bioactivity on the surfaces of Ti and its alloys. It has broad application prospects in biomimetic modification on surface of Ti and its alloys. In this paper, the bioactive ceramic coatings containing Ca and P were prepared by a novel process involving treatment of the MAO and alkali-heat treatment, on which the hydroxyapatite (HA) with a nano-mesh structure was obtained after immersion in simulated body fluid (SBF). The analyses of the morphology, components, phase composition, erosion resistance and bond strength of the coatings was carried out by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), scanning electron microscope (SEM), electro-chemical test and tension test, the formation mechanism of bio-ceramic films and SBF induced HA was discussed as well. The porous oxide ceramic coatings were fabricated in situ on the surface of Ti treated by MAO process in electrolyte containing calcium salt and phosphate. The outer-layer of the coatings has many big pores and part of them appears to be connected with each other; and the inner-layer is denser with small size pores. There is no obvious transition layer between the coating and the Ti substrate. The metallurgic bonding formed in the interface which was in a serrated shape between the coating and the substrate. MAO coatings obtained on titanium are mainly composed of anatase TiO2 and rutile TiO2, and they contain Ca and P ions. The distribution of Ca and P content over the coatings decreases gradually from exterior to interior along the cross-section of the coatings, and the decrease range of Ca is greater than that of P, so the ratio of Ca/P decreases gradually from exterior to interior. Positive voltage of impulse power source is a main parameter affecting the 华 中 科 技 大 学 硕 士 学 位 论 文 IVstructure of MAO coatings. As the voltage increases, the number of pores on surface of the coatings decreases and diameter of pores increases, and the coarseness of surface increases, and the bond strength decreases. When positive voltage was kept at 300V, the ratio of Ca/P on surface of the coatings is 1.77, which is similar to bones in human bodies. According to the results of the electrochemical test, MAO coatings made the self-corrosion potential of titanium increase from -0.4767V to -0.3189V in SBF. It is suggested that the corrosion resistance of the titanium could be obviously improved by MAO process. The optimized parameters for MAO process are: positive voltage is 300V, and negative voltage is 30V, and frequency is 600Hz, and processing time is 5min, and duty ratio is 0.2. The TiO2-based coatings containing the CaTiO3 and Ca2P2O7 nanorods formed on the surface of MAO coatings treated by an alkali and heat treatment. Compared to the MAO coatings, the content of anatase TiO2 decreased and the content of rutile TiO2 increased slightly, the size and porosity of pores decreased simultaneously. Because the micro cracks and shrinkage formed on the surface of the coatings, the bond strength of the coatings decreased slightly. Some floc grains formed near the micro-pores and cracks on the surface of the coatings after alkali-heat treatment when it was immersed in SBF for 3 days. The spherical HA appeared for the immersion of 7 days. After immersio。