Corrosion resistance of plasma-anodized AZ91D magnesium alloy by electrochemical methods
Corrosion resistance of plasma-anodized AZ91D magnesium alloy by electrochemical methods
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DOI：
10.1016/j.electacta.2007.04.030
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发表时间：
2007-12-01
影响因子：
6.6
通讯作者：
Steinmetz, J.
中科院分区：
文献类型：
--
作者：
Barchiche, C. -E.;Rocca, E.;Steinmetz, J.
镁合金等离子体阳极氧化膜主要用于镁合金表面的防腐蚀保护。为获得耐腐蚀性能较好的阳极氧化膜，研究了KOH浓度、阳极氧化时间和电流密度对AZ91D镁合金阳极氧化膜性能的影响。采用扫描电子显微镜（SEM）、电子色散X射线能谱（EDX）、X射线衍射（XRD）和显微拉曼光谱对涂层进行了表征。膜是多孔的和破裂的，主要由氧化镁（MgO）组成，但包含电解质和合金中存在的所有元素。采用静态和动态电化学方法研究了镁合金阳极氧化膜在腐蚀性水中的腐蚀行为。采用电化学方法测定了在较浓的电解液3 M KOH +0.5 M KF+0.25 M Na_3PO_4中心点12 H（2）O、较长的阳极氧化时间和较低的电流密度下获得的最佳耐蚀性。阳极氧化层对镁的腐蚀具有双重电化学效应：抑制阴极过程和稳定钝化平台。(c)2007爱思唯尔有限公司保留所有权利。
Anodic coatings formed on magnesium alloys by plasma anodization process are mainly used as protective coatings against corrosion. The effects of KOH concentration, anodization time and current density on properties of anodic layers formed on AZ91D magnesium alloy were investigated to obtain coatings with improved corrosion behaviour. The coatings were characterized by scanning electron microscopy (SEM), electron dispersion X-ray spectroscopy (EDX), X-ray diffraction (XRD) and micro-Raman spectroscopy. The film is porous and cracked, mainly composed of magnesium oxide (MgO), but contains all the elements present in the electrolyte and alloy. The corrosion behaviour of anodized Mg alloy was examined by using stationary and dynamic electrochemical techniques in corrosive water. The best corrosion resistance measured by electrochemical methods is obtained in the more concentrated electrolyte 3 M KOH +0.5 M KF+0.25 M Na3PO4 center dot 12H(2)O, with a long anodization time and a low current density. A double electrochemical effects of the anodized layer on the magnesium corrosion is observed: a large inhibition of the cathodic process and a stabilization of a large passivation plateau. (c) 2007 Elsevier Ltd. All rights reserved.