Microstructure and in vitro degradation performance of Mg-Zn-Mn alloys for biomedical application.
Microstructure and in vitro degradation performance of Mg-Zn-Mn alloys for biomedical application.
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DOI：
10.1002/jbm.a.34368
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
F. Rosalbino;S. Negri;G. Scavino;Adriana Saccone
中科院分区：
文献类型：
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作者：
F. Rosalbino;S. Negri;G. Scavino;Adriana Saccone
选择锰和锌作为合金元素，考虑到这些金属良好的生物相容性，开发了一种用于生物医学应用的镁基三元合金。采用扫描电子显微镜和能谱分析相结合的方法，研究了含锰量为0.5%和1.0%，含锌量为1.0%和1.5%的镁锌锰合金的显微组织。通过在模拟体液的林格氏生理溶液中进行的动电位极化和电化学阻抗谱测量来评估它们的腐蚀性能。所有被测试的样品都是由镁基固溶体和镁锌二元相组成的两相合金。电化学测试结果表明，随着锌、锰含量的增加，合金的腐蚀行为得到改善。这是由于形成了部分保护的Mg(OH)(2)表面膜，合金元素提高了其保护能力。在表面有部分保护层的情况下，镁锌金属间化合物对镁锌锰合金腐蚀速率的影响减小，这可归因于镁锌锰固溶体与第二相之间的阻力增加，从而降低了微电流腐蚀的有效驱动力。由于其最高的防腐能力，Mg-1.5Zn-1Mn合金是一种很有前途的可降解植入物，如螺丝、板材和棒材。
Manganese and zinc were selected as alloying elements to develop a Mg-based ternary alloy for biomedical applications, taking into account the good biocompatibility of these metals. The microstructures of Mg-Zn-Mn alloys containing 0.5 or 1.0 mass% of manganese and 1.0 or 1.5 mass% of zinc were investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Their corrosion properties were assessed by means of potentiodynamic polarization and electrochemical impedance spectroscopy measurements performed in Ringer's physiological solution that simulates bodily fluids. All tested samples are two-phase alloys formed by a Mg-based matrix, consisting of a Mg-Zn-Mn solid solution, and a Mg-Zn binary phase. The electrochemical results show an improvement of the corrosion behavior of the investigated alloys with increasing Zn and Mn content. This is attributed to the formation of a partially protective Mg(OH)(2) surface film whose protective capabilities are increased by the alloying elements. The reduced influence of the Mg-Zn intermetallic compound on the corrosion rate of Mg-Zn-Mn alloys in the presence of a partially protective surface layer can be ascribed to an increasing resistance between the Mg-Zn-Mn solid solution and the second phase, thereby decreasing the effective driving force for microgalvanic corrosion. Owing to its highest corrosion protective ability, the Mg-1.5Zn-1Mn alloy is a promising candidate for the development of degradable implants, such as screws, plates, and rods.