Studies of the formation of cerium-rich protective films using x-ray absorption near-edge spectroscopy and rotating disk electrode methods
Studies of the formation of cerium-rich protective films using x-ray absorption near-edge spectroscopy and rotating disk electrode methods
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DOI：
10.1149/1.1836400
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发表时间：
1996-01-01
影响因子：
3.9
通讯作者：
Isaacs, HS
中科院分区：
文献类型：
--
作者：
Aldykiewicz, AJ;Davenport, AJ;Isaacs, HS
研究了阴极极化条件下富铈膜在铜表面的沉积过程，作为研究含铜铝合金缓蚀机理的模型体系。沉积也研究了金和。铁与铜比较。通过在含铜金属间化合物上沉积富铈膜来抑制铝合金的腐蚀，所述富铈膜阻止氧在这些部位的阴极还原。X射线吸收近边结构测量表明，富铈膜从曝气溶液中沉淀的四价状态。热力学上，Pourbaix图预测在这些条件下铈应该处于三价状态。这表明铈的化学性质是由溶液中的过程而不是电极的电位决定的。富铈膜的形成取决于氧的还原，其影响溶液中Ce（III）氧化成Ce（IV），并通过改变电极处的局部pH来沉淀膜。通过氧还原产生过氧化氢被认为是通过在溶液中将Ce（III）氧化成Ce（IV）来增强富铈膜的形成。通过向溶液中加入过氧化氢证实了这一点。
The deposition of cerium-rich films on copper under cathodic polarization was studied as a model system for understanding the mechanism of corrosion inhibition of copper-containing aluminum alloys. Deposition was also studied on gold and. iron for comparison with copper. Inhibition of corrosion of the aluminum alloys is achieved by deposition of a cerium-rich film on the copper-containing intermetallics that blocks the cathodic reduction of oxygen at these sites. X-ray absorption near-edge structure measurements show that cerium-rich films precipitated from aerated solutions are in the tetravalent state. Thermodynamically, the Pourbaix diagram predicts that under these conditions cerium should be in the trivalent state. This indicates that cerium chemistry is determined by processes in the solution rather than the potential of the electrode. Cerium-rich film formation is dependent on reduction of oxygen which influences the oxidation of Ce(III) to Ce(IV) in solution and precipitation of the film by changing the local pH at the electrode. The generation of hydrogen peroxide by oxygen reduction is considered to enhance cerium-rich film formation by oxidizing Ce(III) to Ce(IV) in solution. This was confirmed by addition of hydrogen peroxide to the solution.