班朝磊
,
朱淑芹
,
侯加林
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2016.03.031
阐述小孔腐蚀在铝电解电容器用铝箔质量评价中的应用机理。首先简要介绍电容器铝箔立方织构的形成过程和特征,及小孔腐蚀的一般电化学特点；然后模拟计算多晶体铝箔材料各晶面弹性模量、各晶面原子密度和各晶向原子密度；最后用HCl、HNO3、HF组成的特定侵蚀剂对电容器铝箔实施小孔腐蚀,用扫描电子显微镜( SEM)和光学显微镜( OM)对小孔腐蚀后的铝箔表面形貌与横截面形貌进行观察分析。电容器铝箔侵蚀后表面呈现大量正方形蚀孔,电容器铝箔发生小孔腐蚀具有方向性,蚀孔隧道总是沿着垂直或平行于铝箔表面的方向发展；<100>、<110>和<111>晶向的原子密度依次为2/a、2.12/a、1.15/a,a为晶胞参数,{100}、{110}和{111}晶面的原子密度依次为5/a2、4.24/a2、13.85/a2,{100}、{110}和{111}晶面的弹性模量依次为98.418、109.449、113.2678 GPa,蚀孔隧道活性尖端由{111}晶面构成以降低表面能,蚀孔隧道钝化壁由{100}晶面组成以保持钝化膜稳定。电容器铝箔正方形点蚀表面形貌与铝箔织构有特定的对应关系,织构{100}<001>含量可以通过计算铝箔表面正方形蚀坑面积的方法来估算。
关键词:
小孔腐蚀
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铝电解电容器
,
铝箔
,
立方织构
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局部腐蚀
,
钝化
Weimin MAO
,
Heng JIANG
,
Ping YANG
,
Huiping FENG
,
Yongning YU
材料科学技术（英文）
The distribution of microelement Fe, Si, Cu and Mg in the surface layer of aluminum foil annealed at 300℃ and 500℃ were determined by secondary ion mass spectrometer. The corrosion structure produced by electrochemical etching was also observed. It was found that the Mg concentration at external surface was increased exponentially over the fourth degree and promoted by higher annealing temperature, which will increase the number of corrosion pits inside the large grains, and therefore the specific capacity of the foils for electrolytic capacitors. The similar effects of microelement Fe, Si and Cu were not so strong.
关键词:
Electrolytic capacitor
,
null
,
null
,
null
Jingbo SONG
,
Weimin MAO
材料科学技术（英文）
The effect of trace Sn on the pitting morphology of high voltage anode aluminum foils was investigated. The distributions of microelement Sn, Fe, Si, Cu and Mg in the surface layer of aluminum foils with different Sn content were determined by using a secondary ion mass spectrometer. It was found that the micro-alloyed Sn is enriched at the external surface. The mechanism of pitting behavior of trace Sn on aluminum surface is similar with that of lead. Enrichment of Sn in the surface layer provides large numbers of sites for initiation of pitting corrosion, while pitting sites appeared relatively inhomogenously in the foils without Sn. Sn, as an eco-friendly microelement, can be applied to replace Pb in improving the homogenous pitting behaviors of high voltage aluminum foils, in which the volume fraction of cube texture is not reduced.
关键词:
Electrolytic capacitor
,
铝箔
,
锡
,
孔腐蚀
