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Cu-Zn-Al SMA和TAMZ在模拟体液中的耐蚀性及牺牲阳极法制备HAP涂层
Corrosion Resistance of Cu-Zn-Al SMA and TAMZ Alloy in Simulated Body Fluids and Preparation of HAP Coating by Sacrificial Anode Method
【作者】 陈邦义；
【导师】 梁成浩；
【作者基本信息】 大连理工大学 ， 化学工程， 2006， 博士
【摘要】 生物医用金属材料的使用在提高人类生活质量方面发挥了巨大的作用。然而,金属材料植入人体后,在体液中不可避免地会发生腐蚀。腐蚀不仅会降低金属材料的力学和机械性能,甚至导致植入失效,而且,溶入体液的金属离子对周围组织会产生一定的副作用,严重的则引发组织病变或者癌变。因此,医用金属材料的耐蚀性研究对于保障其在人体内的安全使用具有十分重大的现实意义。 羟基磷灰石（hydroxyapatite,HAP）以其优异的生物相容性和生物活性而引起了研究工作者的极大兴趣,其力学和机械性能不能满足承力植入材料的要求。将金属材料和HAP复合综合了各自的优点,是一类极具发展前途的生物材料。开发低温低成本HAP涂层制备方法吸引了众多研究者的兴趣。 本文研究了Cu-Zn-Al SMA和TAMZ钛合金生物材料在模拟体液中的耐蚀行为,并采用牺牲阳极法在TAMZ合金表面制备生物活性HAP涂层,得出如下的结论: （1）pH 7.2的模拟宫腔液中,紫铜和Cu-Zn-AI SMA的腐蚀速率分别为66.42、7.21 p∥d,在模拟宫腔液中紫铜和Cu-Zn-Al SMA电化学反应主要受阴极氧的去极化控制。 （2）Cu-Zn-Al SMA在模拟宫腔液中发生小孔腐蚀,其在pH 7.2的模拟宫腔液中的临界孔蚀电位为1.70V（SCE）。小孔形貌有两种,分别为龟贝状和不规则溃疡状。Cu-Zn-AlSMA在模拟宫腔液中蚀孔发展的动力学方程为:i0=465.68t-0.5+1.5。 （3）在分析生理盐水中Cu-Zn-Al SMA腐蚀形貌的基础上,提出了Cu-Zn-Al SMA在模拟体液中的腐蚀模型。腐蚀产物最外层为碱式铝盐和锌盐,其次为由溶入溶液中的铜离子发生阴极沉积反应而形成的由铜组成的沉积铜层。脱成分（锌和铝选择性溶解）腐蚀层为腐蚀最里层,由铜和少量的锌和铝组成。 （4）化学镀镍磷表面改性及BTA钝化法可在金属基体表面形成性能稳定的阻碍膜层,显著提高Cu-Zn-Al SMA在模拟体液中的耐蚀性能。化学镀镍磷表面改性在Cu-Zn-AlSMA基体表面形成非晶态镀层,BTA法钝化方法在Cu-Zn-Al SMA表面形成了Cu（Ⅰ）-BTA和Cu（Ⅱ）—BTA的络合物的表面膜。 （5）腐蚀电位测试和极化曲线测试结果表明,在模拟体液中,TAMZ合金具有最优的热力学稳定性和电化学稳定性。这是由于在TAMZ合金属β相结构,具有最佳的热力学稳定性和电化学稳定性。
【Abstract】 The application of biomedical metals exerts huge effect on promoting living quality of human beings. However, when being implanted into body, metals would be corroded inevitably resulting from the influence of body fluid, which will decrease the mechanical properties of metals, even result in implantation failure. And the metal ions dissolved into body fluid have some side effect on the surrounding tissue, even leading to pathological changes or carcinomatous alteration. Hence, studies on corrosion resistance of biomedical metals have important practical sense in guaranteeing their safe application.Owing to good bioactivity and biocompatibility, hydroxyapatite （HAP） has attracted much interest of researchers. The materials that combine advantages of metals and HAP is a promising biomaterial. The preparation method of HAP coating at low temperature attracts many attentions of researchers.In this article, corrosion behavior of Cu-Zn-Al SMA and TAMZ Ti alloy （TAMZ） was investigated. And sacrificial anode method was applied to prepare bioactive HAP coating on TAMZ. The results were as follows:1) Corrosion rates of Cu and Cu-Zn-Al SMA in pH 7.2 simulated uterine fluid were 66.42、 7.21μ g/d, respectively. The electrochemical reaction was mainly controlled by cathodic reduction of oxygen.2) Cu-Zn-Al SMA occurred pitting corrosion in simulated uterine fluid. The critical pitting potential in pH 7.2 simulated uterine fluid was 1.70 V（SCE）. And the dynamic equation of pitting development was i0 = 465.68 t-0.5 + 1.5.3) The corrosion model of Cu-Zn-Al SMA in simulated body fluids was proposed based on the analysis of Cu-Zn-Al SMA corrosion morphology in saline solution. The outmost layerwas salt of zinc and aluminum. Next was the deposition Cu layer, then was the selective dissolution layer..4) The inhibitive film was formed on the surface of Cu-Zn-Al SMA by Ni-P electroless plating and BTA passivation method, which improved electrochemical stability of Cu-Zn-Al SMA. Ni-P electroless plated method could produce amorphous layer. Complexes of Cu（ I ）— BTA and Cu（II）—BTA were formed on the surface of Cu-Zn-Al SMA by BTA passivation method.5) The results of corrosion potential and polarization curves showed that TAMZ possessed the best electrochemical stability. TAMZ had the P phase structure, which possessed the best thermal dynamic stability and electrochemical stability.6) HAP coating could be prepared on TAMZ by the single chamber and dual chambers method successfully. The sacrificial method had the characteristic of easy operation, economic and good repetition, with a promising future.7) The mechanism of the dual chambers method was in accordance with electro deposition method. A CaHPO4 ? 2 H2O layer was formed on the metallic substrate firstly, than this layer transformed into HAP through a steam treatment. The mechanism of the single chamber method was controlled by temperature. When the temperature for preparation of initial coating was 20℃, 40℃ and 60℃, the mechanism was the same as electro deposition method. At 80℃, a calcium deficient hydroxyapatite （CDHA） was formed firstly, then it transformed into HAP through a hydrothermal treatment.