VERFAHREN ZUR HERSTELLUNG EINER ALUMINIUMFOLIE FUER ELEKTROLYTKONDENSATOREN UND ELEKTROLYTKONDENSATOR AUS SO HERGESTELLTEN ALUMINIUMFOLIEN.

摘要

The feature is that Aluminium-foil receives first a satinising treatment in a chloride-soln. at about 90 deg.C. with an electrical bias consisting of a waveform with a frequency between 20 and 400 Hz and a duty-cycle of greater than 40%, pref. of 50%. The total amt. of charge used is low, pref. between 2 and 5 Coulomb/sq.cm. This treatment is followed by anodic etching of the foil in a suitable electrolyte using a bias consisting of pulses superimposed on a DC-bias or of a pulsed DC-bias. The pulses have pref. a polarity and amplitude which causes the etching to be periodically interrupted briefly and followed by a forming period. An electrolytic capacitor made using the foil prepd. as above is also claimed.