Anode aluminum foil is etched in H2SO4 and HC1 solutions to meet the development tendency of high capacitance and miniaturization for making aluminum electrolytic capacitor. But the currently etching technology often result in the tunnels etched with large sizes and distributed no-uniformly, thereby restricting the further increase of capacitance. Here we find that the passive current density of aluminum foil is increased and the pit potential is decreased when H2SO4 concentration is raised, as shown in the anodic polarization curves. These results demonstrate that the dissolving rate of passive film is increased with H2SO4 concentration. So a solution with higher concentration of H2SO4 and lower concentration of HC1 has been used to etch aluminum foil to acquire tunnels with small and symmetrical sizes and uniform distribution on surface, which has been evaluated by the sizes statistics. Therefore, anode aluminum foils with higher capacitance can be obtained eventually.
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机译：在H2SO4和HC1溶液中蚀刻阳极铝箔，以满足制备铝电解电容器的高电容和小型化的开发趋势。但是当前蚀刻技术通常导致隧道以大尺寸和均匀分布，从而限制电容的进一步增加。在这里，我们发现铝箔的被动电流密度增加，并且当升高H2SO4浓度时，凹坑电位减小，如阳极偏振曲线所示。这些结果表明，随着H2SO4浓度增加了无源膜的溶解速率。因此，具有较高浓度H 2 SO 4和较低浓度HC1的溶液已经用于蚀刻铝箔，以获得具有小且对称尺寸的隧道，并且表面上的均匀分布，这已经通过尺寸统计评估。因此，最终可以获得具有较高电容的阳极铝箔。
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