Purpose

This paper aims to focus on an assessment of the electrochemical corrosion performance of bulk NC copper in a variety of corrosion environments.

Design/methodology/approach

The electrochemical corrosion behavior of bulk nanocrystalline (NC) copper prepared by inert gas condensation and in situ warm compress technique was studied by using potentiodynamic polarization and electrochemical impedance spectroscopy tests in de-aerated 0.1 M NaOH solution.

Findings

NC copper exhibited a typical active-passive-transpassive behavior with the formation of duplex passive films, which was qualitatively similar to coarse-grain (CG) copper. Although a compact passive film formed on NC copper surface, the corrosion resistance of NC copper was lower in comparison with CG copper. The increase in corrosion rate for NC copper was mainly attributed to the high activity of surface atoms and intergranular atoms. These atoms led to an enhancement of passive ability and an increase of dissolution rate of passive film in oxygen-deficiency solution. For NC copper, the corrosion resistance decreased as grain size increased in NC range.

Originality/value

The difference in corrosion resistance between bulk NC copper and its CG counterpart is dependent upon the corrosion solution. In a previous work, the potentiodynamic polarization tests revealed that NC copper bulks (grain size 48, 68, 92 nm) had identical corrosion resistance to CG copper bulk in naturally aerated 0.1 M NaOH solution. The results might be related to the dissolved oxygen in the medium.

中文翻译：

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块状纳米晶铜在碱性溶液中的电化学腐蚀行为和表面钝化

目的

本文旨在重点评估在各种腐蚀环境下块状NC铜的电化学腐蚀性能。

设计/方法/方法

利用电势极化和电化学阻抗谱测试在0.1 M NaOH脱气溶液中研究了惰性气体冷凝和原位热压技术制备的块状纳米晶铜的电化学腐蚀行为。

发现

NC铜表现出典型的主动-被动-被动行为，并形成了双面无源膜，其质量与粗晶粒（CG）铜类似。尽管在NC铜表面上形成了致密的钝化膜，但与CG铜相比，NC铜的耐腐蚀性较低。NC铜腐蚀速率的增加主要归因于表面原子和晶间原子的高活性。这些原子导致缺氧溶液中钝化能力的增强和钝化膜溶解速率的增加。对于NC铜，其耐腐蚀性随NC范围内晶粒尺寸的增加而降低。

创意/价值

大块NC铜和其CG对应物之间的耐蚀性差异取决于腐蚀液。在以前的工作中，电势极化测试表明，在自然充气的0.1 M NaOH溶液中，NC铜块（粒度48、68、92 nm）与CG铜块具有相同的耐腐蚀性。结果可能与介质中的溶解氧有关。