Surface chemistry of bulk nanocrystalline pure iron and electrochemistry study in gas-flow physiological saline.
Surface chemistry of bulk nanocrystalline pure iron and electrochemistry study in gas-flow physiological saline.
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DOI：
10.1002/jbm.b.32713
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发表时间：
2012-07
期刊：
影响因子：
--
通讯作者：
F. Nie;Y. Zheng
中科院分区：
文献类型：
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作者：
F. Nie;Y. Zheng
传统的微晶纯铁(MC-Fe)物理性能不足，生物降解性能较差，是一种新型的可生物降解金属。为了克服这些问题，本工作采用等通道转角挤压技术制备了新型块体纳米晶纯铁。与水和甘油液滴的接触角测试表明，NC-Fe的接触角小于MC-Fe，这意味着NC-Fe的表面能较低。与MC-Fe相比，NC-Fe的表面粗糙度有较大幅度的增加。进一步对比研究了NC-Fe和MC-Fe在不同溶氧浓度的生理盐水中的腐蚀和电化学性能，以期在体外模拟生理环境中冠状动脉支架的腐蚀过程。电化学阻抗谱分析和阳极极化测试表明，NC-Fe比MC-Fe具有更高的耐蚀性，同时随着溶解氧浓度的降低，耐蚀性也有明显的提高。进一步讨论了相关的等效电路模型和表面重构过程，建立了MC-Fe和NC-Fe的降解机理。
Conventional microcrystalline pure iron (MC-Fe) becomes a new candidate as biodegradable metals, which has the insufficient physical feature and inferior biodegradation behavior. Novel bulk nanocrystalline pure iron (NC-Fe) was fabricated via equal channel angular pressing technique in the present work to overcome these problems. The contact angle test with water and glycerol droplets shows a smaller angle (though >90°) of NC-Fe than that of MC-Fe, which implies a lower surface energy of NC-Fe. The surface roughness of NC-Fe increased greatly than that of MC-Fe. A further comparative study of corrosion and electrochemistry performance between NC-Fe and its original MC-Fe was investigated in physiological saline with different dissolved oxygen concentration, aiming to in vitro simulate the corrosion process of coronary stent occurred in physiological environment. The electrochemical impedance spectra analysis and anodic polarization measurements indicated that the NC-Fe exhibited higher corrosion resistance than that of the MC-Fe; meanwhile obvious enhanced corrosion resistance with the decrement of dissolved oxygen concentration was observed. Related equivalent circuit model and surface reconstruction process were further discussed, and the degradation mechanism of the MC-Fe and NC-Fe were finally established.