High corrosion resistance of magnesium coated with hydroxyapatite directly synthesized in an aqueous solution
High corrosion resistance of magnesium coated with hydroxyapatite directly synthesized in an aqueous solution
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DOI：
10.1016/j.electacta.2009.07.033
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发表时间：
2009-11-30
影响因子：
6.6
通讯作者：
Yamamoto, Akiko
中科院分区：
文献类型：
--
作者：
Hiromoto, Sachiko;Yamamoto, Akiko
防腐涂层对于镁合金的实际应用是至关重要的，其用于减轻车辆、飞机、电子外壳等的重量。羟基磷灰石（HAp）潜在地提供高的耐腐蚀性并且没有环境毒性，因为其热力学结构稳定性高并且是骨的基本组分。然而，在水溶液中在镁上直接合成HAp一直是科学挑战，因为镁离子阻止HAp结晶。开发了一种使用Ca螯合物在镁上直接合成HAp的新方法，该方法可以在镁表面保持足够高的Ca离子浓度以克服Mg离子对HAp结晶的阻碍。在纯镁和AZ系列合金上成功地形成了高度结晶的HAp涂层。通过在纯镁表面进行1gm（-2）NaCl的干湿循环腐蚀试验和在3.5wt%NaCl溶液中的极化试验，研究了羟基磷灰石涂层纯镁的腐蚀行为。在干和湿测试之后，HAp-coated纯镁没有显示出明显的腐蚀坑。在极化测试中，羟基磷灰石涂层试样的阳极电流密度比抛光试样低10（3）-10（4）倍。结果首次证明HAp涂层在镁表面具有显着的防腐蚀性能。(C)2009爱思唯尔有限公司保留所有权利。
Anticorrosion coatings are crucial for practical applications of magnesium alloys, which are used to reduce the weight of vehicles, aircraft, electronics enclosures etc. Hydroxyapatite ( HAp) potentially offers high corrosion resistance and no environmental toxicity because its thermodynamic structural stability is high and it is a basic component of bone. However, direct synthesis of HAp on magnesium in aqueous solutions has been a scientific challenge because Mg ions prevent HAp crystallization. A new method of direct synthesis of HAp on magnesium was developed using a Ca chelate compound, which can maintain a sufficiently high concentration of Ca ions on the magnesium surface to overcome prevention of HAp crystallization with Mg ions. Highly crystallized HAp coatings were successfully formed on pure magnesium and AZ series alloys. Corrosion behavior of HAp-coated pure magnesium was examined by cyclic dry and wet tests with 1 gm(-2) NaCl on the surface and polarization tests in a 3.5 wt% NaCl solution. A HAp-coated pure magnesium showed no noticeable corrosion pits after the dry and wet test. HAp-coated specimens showed 10(3)-10(4) times lower anodic current density than as-polished specimen in the polarization test. The results demonstrate the remarkable anticorrosion performance of HAp coatings on magnesium for the first time. (C) 2009 Elsevier Ltd. All rights reserved.