Change in Oxygen Reduction Reactivity of Intermetallics: A Mechanism of the Difference in Trenching around Al-Fe and Al-Fe-Si Particles on AA1050 in NaCl
Change in Oxygen Reduction Reactivity of Intermetallics: A Mechanism of the Difference in Trenching around Al-Fe and Al-Fe-Si Particles on AA1050 in NaCl
复制标题
DOI：
10.1149/1945-7111/acb6ba
复制
发表时间：
2023-02-01
影响因子：
3.9
通讯作者：
Hara, Nobuyoshi
中科院分区：
文献类型：
--
作者：
Kakinuma, Hiroshi;Muto, Izumi;Hara, Nobuyoshi
通过原位观察分析了AA 1050铝在0.1 M NaCl中pH 6.0时金属间化合物颗粒周围的沟槽。在Al-Fe-Si颗粒周围形成深沟槽，而在Al-Fe颗粒周围不形成深沟槽，深沟槽成为点蚀的起始位置。测量了无金属间化合物颗粒的AA 1050合金的块体金属间化合物和铝基体的开路电位。结果表明，在自然浸泡条件下，Al-Fe-Si和Al-Fe颗粒被AA 1050的Al基体阴极极化。发现这种阴极极化改变了金属间化合物颗粒的氧还原反应性。抛光状态下，Al-Fe块体的阴极反应性高于Al-Fe-Si块体。恒电位阴极极化后，体相Al-Fe的阴极反应活性降低，而体相Al-Fe-Si的阴极反应活性增加。微电化学测量和表面分析澄清了金属间化合物颗粒的阴极反应性的变化在AA 1050铝上开槽中起着关键作用。
Trenching around intermetallic particles on AA1050 aluminum in 0.1 M NaCl at pH 6.0 was analyzed by in situ observations. Deep trenches, which become the initiation site for pitting, were formed around the Al-Fe-Si particles but not around the Al-Fe particles. The open-circuit potentials of the bulk intermetallic compounds and Al-matrix of AA1050 without intermetallic particles were measured. It was determined that the Al-Fe-Si and Al-Fe particles were cathodically polarized by the Al-matrix of AA1050 under natural immersion conditions. This cathodic polarization was found to change the oxygen reduction reactivity of the intermetallic particles. The cathodic reactivity on bulk Al-Fe was higher than that on bulk Al-Fe-Si under as-polished condition. However, after potentiostatic cathodic polarization, the cathodic reactivity on bulk Al-Fe decreased, whereas that on bulk Al-Fe-Si increased. Micro-electrochemical measurements and surface analyses clarified that the change in the cathodic reactivity of the intermetallic particles plays a critical role in trenching on AA1050 aluminum.