The effect of indium impurity on the DC-etching behaviour of aluminium foil for electrolytic capacitor usage

摘要

The effects of indium impurity on the etched morphology of high purity aluminium foils for electrolytic capacitor useage were investigated. The indium impurity was present either in as-received aluminium foils or deposited purposely on the foil surface through immersion-reduction reaction. The rolling line effect can be improved through introducing deposited indium on foil surfaces by immersion of the foil into In(NO_3)_3 solution prior to DC-etching. Under a high immersion temperature and more concentrated in(NO_3)_3 condition, surface etching competes with tunnel etching, and the foil thickness clearly decreases.