CURVATURE EFFECTS IN ALLOY DISSOLUTION
CURVATURE EFFECTS IN ALLOY DISSOLUTION
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DOI：
10.1149/1.2220924
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发表时间：
1993-10-01
影响因子：
3.9
通讯作者：
SIERADZKI, K
中科院分区：
文献类型：
--
作者：
SIERADZKI, K
单质金属可以在低恒电位的扭结处溶解，不产生新的界面面积。当理想固溶体合金经历选择性溶解时，由于原子尺度的无序，这种情况是不可能发生的。只有在固体表面注入负曲率区域才能溶解较不贵重的成分，这增加了界面面积。我们提出了一个热力学分析，解释了这些毛细管效应在合金溶解中的作用。从动力学粗化转变的角度分析了宏观选择性溶解临界电位现象。这种转变是曲率依赖性溶解和表面扩散之间竞争的结果。提出了临界电位随合金成分变化的表达式。脱合金阈值对应于定义粗化转变的临界电位线上的一个临界成分。
An elemental metal can dissolve at kink sites at low everpotentials producing no new interfacial area. When an ideal solid solution alloy undergoes selective dissolution, this situation is not possible owing to atomic-scale disorder. Dissolution of the less noble constituent can proceed only by injection of regions of negative curvature into the solid surface, which increases the interfacial area. We present a thermodynamic analysis which accounts for these capillary effects in alloy dissolution. The phenomenon of the critical potential for macroscopic selective dissolution is analyzed in terms of a kinetic roughening transition. This transition results from a competition between curvature-dependent dissolution and surface diffusion. An expression for the critical potential as a function of alloy composition is developed. The dealloying threshold corresponds to a critical composition on the line of critical potentials defining the roughening transition.