生物医用TiNi形状记忆合金及Co合金腐蚀速率测量

Corrosion Rate Measurements of Biomedical TiNi Shape Memory Alloy and Cobalt Alloys

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Ti Ni形状记忆合金、Co Cr Ni W和 Co Cr Ni Mo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 ,其中 Co Cr Ni Mo合金耐蚀性最优。暂态线性极化法和原子吸收法测得 Ti Ni、Co Cr Ni W和Co Cr Ni Mo的腐蚀速率分别为 0 .0 691、0 .0 490 μm/ a、0 .0 3 83及 0 .0 5 95、0 .0 5 2 8、0 .0 3 87μm/ a,而前三种方法所测合金腐蚀速率较后两种方法的结果大一个数量级 ,这可能与电化学方法的适用性及合金的表面状态有关。暂态线性极化法可以方便迅速地测定耐蚀合金的腐蚀速率值 ;原子吸收光谱法直接测得进入溶液的金属离子的浓度 ,能够为材料的生物相容性的评价提供参考 。

The corrosion rates of TiNi, CoCrNiW and CoCrNiMo 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. Results indicated that corrosion rates of these three alloys were very low due to their excellent corrosion resistance and the corrosion resistance of CoCrNiMo was the best. Corrosion rates of TiNi, CoCrNiW and CoCrNiMo were 0.691, 0.0595, 0.0490 μm/a and 0.0528, 0.0383, 0.0387 μm/a, respectively. The results measured by the first three methods were about ten times of those by the latter two methods, and this was related to the applicability of each method and the alloy surface state. Transient linear polarization technique can determine low corrosion rate conveniently and quickly. Atomic absorption spectroscopy method, determining directly the concentration of ion in solution, provide reference for material biocompatibility. And these two methods are properly used in measuring corrosion rates for biomedical materials.