Title:
PRODUCTION OF ELECTRODE FOR ALUMINUM ELECTROLYTIC CAPACITOR
Document Type and Number:
Japanese Patent JPS5576098
Kind Code:
A
Abstract:
PURPOSE:To form an aluminum electrode foil of a high surface expansion rate and tensile strength by letting sodium hyposulfite exist in a high-concentration high- temperature hydrochloric acid solution and applying DC electrolytic etching under the specific conditions. CONSTITUTION:At the time of expanding the surface area of an Al metal foil through electrolytic etching, sodium hyposulfite is added at 2-6% into the bath of HCl concentrations 3-15%, and while the solution temperature is being maintained at 75 deg.C or more, the foil is pretreated by using the electric quantity of DC 2- 30 Coulomb/cm<2>, after which it is subjected to deep etching at current density 0.02-0.1A/cm<2> DC at the same temperature, whereby the pits of diameters made 4 times larger than those by conventional methods are formed. Because of this, the decrease in surface expansion rate in the high pressure region is small and since the shape of the pits becomes perpendicular and regular cylindrical form, the surface expansion rate becomes extremely high.
Inventors:
YAMAZAKI TADASHI
Application Number:
JP14967978A
Publication Date:
June 07, 1980
Filing Date:
December 05, 1978
Export Citation:
Assignee:
FUJITSU LTD
International Classes:
C25F3/04; H01G9/04; (IPC1-7): C25F3/04; H01G9/04