Porous Tantalum Anodes for Liquid and Solid Electrolytic Capacitors by Reaction in Situ

Abstract

A new porous tantalum capacitor anode for liquid and solid electrolytic capacitors, prepared directly by the reaction in situ of and C is described. Porous in situ anodes with total interstitial contents (C, O, and N) of less than 0.02%, metallic impurity contents less than the limit of chemical analytical detection, densities of approximately 4–12 g/cc, and specific capacitances of 1600–3200 μcoul/g were evaluated. Life tests of 1000 hr showed only slight changes in electrical characteristics for liquid electrolytic capacitors tested at 125v and 85°C and solid electrolytic capacitors tested at 34v and 125°C.