Corrosion behaviour of Sn-containing oxide layer on AZ91D alloy formed by plasma electrolytic oxidation
Corrosion behaviour of Sn-containing oxide layer on AZ91D alloy formed by plasma electrolytic oxidation
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DOI：
10.1016/j.surfcoat.2008.03.010
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发表时间：
2008-05-25
影响因子：
5.4
通讯作者：
Hazan, J.
中科院分区：
文献类型：
--
作者：
Barchiche, C. -E.;Rocca, E.;Hazan, J.
镁合金的腐蚀现象是限制镁合金在汽车和航空航天工业中应用的主要因素之一。在KOH/KF/Na 3 PO 4电解液中，采用恒电流等离子体电解氧化法在AZ 91 D镁合金表面制备含Sn的氧化物保护膜。利用SEM结合EDS、XRD和拉曼光谱对薄膜的形貌和成分进行了分析。在氧化物中，锡主要作为结晶MgSn（OH）（6）化合物结合在层中。AZ 91 D镁合金表面锡氧化物涂层的主要性能是在开路条件下将腐蚀速率保持在可接受的值，并提供足够的钝化平台以降低点蚀敏感性。点蚀试验揭示的泡沫特性解决了镁合金在使用中经常发生重要电偶耦合的主要缺点。因此，在电解液中添加低浓度的锡酸盐以在镁合金上形成富含Sn的阳极氧化物代表了一种有趣的方式来在短时间的阳极氧化中通过PEO合成保护涂层。(C)2008 Elsevier B. V.保留所有权利。
Corrosion phenomenon of magnesium alloys is one of the limits for using magnesium alloys in automotive and aerospace industries. The aim of this study is the development of Sn-containing protective oxide coating by a simple plasma electrolytic oxidation in KOH/KF/Na3PO4 electrolyte on AZ91D magnesium alloy in galvanostatic mode. The film morphology and composition were analysed by SEM coupled with EDS, XRD and Raman spectroscopy. In the oxide, tin is mainly incorporated as crystallised MgSn(OH)(6) compound in the layer. The main properties of Sn-containing oxide coating on AZ91D are both keeping the corrosion rate at open-circuit conditions at an acceptable value, and providing a sufficient passivation plateau to reduce the pitting sensibility. The lather characteristic, revealed by pitting tests, addresses the major drawback of magnesium alloys which often undergo important galvanic coupling in service. Consequently, the addition of low stannate concentration in the electrolyte to form Sn-rich anodic oxide on magnesium alloys represents an interesting way to synthesize protective coatings by PEO in a short time of anodization. (C) 2008 Elsevier B.V. All rights reserved.