【作者】 郭海霞；

【导师】 梁成浩；

【作者基本信息】 大连理工大学 ， 电化学工程， 2001， 硕士

【摘要】 本文考察了生物医用材料TiNi形状记忆合金、CoCrNiW、CoCrNiMo合金及其离子注入改性材料的电化学性能和血液相容性。 采用动电位线性极化法、四点弱极化法、曹楚南弱极化法、暂态线性极化法及原子吸收光谱法测定了三种合金在模拟人体血液Tyrode’s溶液的腐蚀速率。结果表明，三种合金腐蚀速率低，耐蚀性良好。原子吸收光谱法直接测得进入溶液的金属离子的浓度，是一种直观适用的测量生物医用材料腐蚀速率的方法。 利用电化学测试技术、物理检测手段及血液相容性体外测试法评价了三种合金的电化学行为与血液相容性，并考察了流动、充气及纤维蛋白原对合金极化性能的影响。结果表明，三种合金的钝化区间宽，维钝电流密度小，表现出优异的耐全面腐蚀性能。通过电位扫描曲线滞后环面积及扫描电镜观察发现，TiNi合金具有较大的点蚀倾向，而两种钴合金耐点蚀性能良好。介质流动对钴合金阳极行为的影响不明显，但TiNi的点蚀击穿电位E_b值随着介质流速的增加而显著下降。介质充气后氧的极限扩散电流密度增大，对材料的侵蚀性增强。溶液中添加纤维蛋白原后，纤维蛋白原以络合物的形式吸附在合金表面，其电化学迁移作用破坏了合金表面的钝性氧化膜，导致其阳极性能变劣。扫描电镜观察发现，纤维蛋白原在合金表面分布不连续。由紫外吸收法测得TiNi、CoCrNiW及CoCrNiMo合金对纤维蛋白的吸附量分别为9.667μg/cm~2、9.561μg/cm~2和10.628μg/cm~2。血液相容性的测定结果表明，TiNi合金的血液相容性及表面性能优于CoCrNiW和CoCrNiMo合金。 对三种合金分别进行单离子和双离子注入后考察其电化学性能和血液相容性。结果发现，合金的电化学稳定性显著提高，动态凝血时间延长，溶血率下降，阳极极化性能和血液相容性均得到改善，且双离子注入较单离子注入效果更佳。对双离子注入合金进行X射线衍射分析发现，合金表面主要形成了金属碳化物、氧化物及金属间相，这些弥散分布的硬质相及合金表面的无序膜层阻止了元素的溶解，改善了合金的耐蚀性及血液相容性。更多还原

【Abstract】 The electrochemical property and haemocompatibility of biomedical TiNi shape memory alloy, CoCrNiW, CoCrNiMo and their specimens of ion implantation modification had been investigated in the dissertation. The corrosion rates of three alloys were measured in Tyrode’s solution with potentiodynamic linear polarization, fore-point weak polarization, Cao Chunan weak polarization, transient linear polarization and atomic absorption spectroscopy method. It was shown that the corrosion rates of three alloys were very low due to their excellent corrosion resistance. Atomic absorption spectroscopy method, determining directly the concentration of ion in solution, was a direct and proper technique measuring corrosion rates for biomedical materials. By electrochemical technique, physical detection method, the electrochemical behavior, haemocompatibility, and the effect of flowing, aerating and fibrinogen on polarization were studied. Results indicated that three alloys, with extensive passive region and small passive current, exhibited good resistance to general corrosion. According to the hysteresis loop and picture of SEM, TiNi was susceptible to pitting corrosion while cobalt alloys were resistant to it. Flowing solution almost didn’t do obvious difference to anodic polarization of cobalt alloys. But pitting potential Eb of TiNi decreased markedly with the increasing of velocity. The aggressiveness of aerated solution accreted by increasing the limit diffusion current density of oxygen. When fibrinogen was added to the solution, it formed complex on alloy surface and its electrochemical transference destroyed the passive oxide film, decreasing the passivation property of alloys. SEM pictures told that the distribution of fibrinogen absorbed on surface was un-successive. The adsorption amount measured by UV rayabsorption was respectively 9.667pg/cm:, 9.56lpg/cm’ and l0.628pg/cm2 on TiNi,CoCrNiW and CoCrNiMo. The results of haemocompatibility measurement showedthat TiNi had better haemocompatibility and surface property than CoCrNiW andCoCrNiMo.Aner single and double ion-implantation the electrocheAncal property andhaemocompatibility of alloys were investigated. lt was fOund that the electrochemicalstability was significantly improved, dynamic clotting time was prolonged andhemolysis rate decreased after ion implafltation. All the results poinied out that theanodic polarization property and haemocompatibility were improved by ion plantationand dual implantation was better than single plantation. X-ray diffraction analysis ofalloys after dual implantation revealed that metal carbides, oxids and illtermetallicphases fOrmed on surface. And these phases dispersing on the alloy surface and theamorphous film prevented the dissolving of elements and improved the corrosionresistance and haemocompatibility.更多还原