Pitting and pitting control of Al in gluconic acid solutions - Polarization, chronoamperometry and morphological studies
Pitting and pitting control of Al in gluconic acid solutions - Polarization, chronoamperometry and morphological studies
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DOI：
10.1016/j.corsci.2010.05.032
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发表时间：
2010-09-01
影响因子：
8.3
通讯作者：
El-Lithy, Abdallah S.
中科院分区：
文献类型：
--
作者：
Amin, Mohammed A.;El Rehim, Sayed S. Abd;El-Lithy, Abdallah S.
研究了铝在葡萄糖酸(HG)溶液中的阳极行为。Al被发现在这样的解决方案中发挥了作用。在击穿电位(E(B))以外记录的扫描电子显微镜图像的表面和横断面图显示，发生了强烈的点蚀攻击，形成了大的半球形坑。还研究了添加环境友好的无机缓蚀剂(钨酸盐、钼酸盐或硅酸盐)对铝在汞溶液中的点蚀行为的影响。基于极化和计时安培技术，在各种实验变量的影响下进行了测量。这些测量得到了电极表面的非原位扫描电子显微镜(SEM)和能量色散X射线(EDX)检查的补充。这些化合物在HG溶液中的存在降低了钝化电流密度(j(Pass))，增加了Eb。计时电流测量表明，在HG溶液中，由于钝化氧化膜的生长，阳极电流密度先减小，然后随着Me的增加而增大，t(I)，最后达到一个稳态值。随着外加阳极电位和HG浓度的增加，t(I)值缩短，稳态电流增大，相应地增加了孔洞的萌生和长大速率。坑形核速度(t(I)(-1))随所引入缓蚀剂的类型和浓度的不同而降低。这些化合物的抑制作用顺序为：Si(2)O(5)(2-)>；WO(4)(2-)>；WO(4)(2-)>；MoO(4)(2-)(2-)。(C)2010爱思唯尔有限公司。保留所有权利。
The anodic behaviour of Al in gluconic acid (HG) solutions was studied. Al was found to pit in such solutions. Surface and cross-sectional views of the SEM images recorded beyond the breakdown potential (E(b)) revealed the occurrence of intense pitting attack with the formation of large hemispherical pits. The effect of adding some environmentally acceptable inorganic inhibitors (tungstates, molybdates or silicates) on the pitting corrosion behaviour of Al in HG solutions was also studied. Measurements were carried out under the influence of various experimental variables based on polarization and chronoamperometric techniques. These measurements were complemented by ex situ scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) examinations of the electrode surface. The presence of these compounds in HG solutions decreased the passive current density (j(pass)) and increased Eb. In HG solutions, chronoamperometric measurements showed that the anodic current density first decreased, due to growth of a passive oxide film, then increased withme after a pit incubation time, t(i) and finally attained a steady-state value. Value of t(i) was shortened and simultaneously the steady-state current was elevated, corresponding to an increase in the rate of pit initiation and growth, with increasing applied anodic potential and HG concentration. The rate of pit nucleation (t(i)(-1)) was found to decrease to an extent depending on the type and concentration of the introduced inhibitor. The inhibitory effect of these compounds decreased in the order: Si(2)O(5)(2-) > WO(4)(2-) > WO(4)(2-) > MoO(4)(2-). (C) 2010 Elsevier Ltd. All rights reserved.