Electrode for electrolytic capacitor and process of producing the same

Abstract

An anode for an electrolytic capacitor includes a porous body having micropores that include a dielectric layer filled thereon and an electrolyte filled therein. The porous body includes a laminate of a plurality of sinter layers having the micropores formed from valve metal particles. The laminate includes alternating smaller micropore-size regions and larger micropore-size regions, which form electric conductive passages between the smaller micropore-size regions and side surfaces of the porous body. This structure reduces resistance of the capacitor and also increases capacitance by effectively utilizing the capacitance of the smaller micropore-size regions. The porous body is formed by stacking a plurality of porous preforms, such as sheets preformed of valve metal powder, into a laminate, and then sintering the laminate. The porous body may be joined with a valve metal substrate during sintering, thereby completing the anode for an electrolytic capacitor. Particularly, the porous body may be a laminate including larger micropore-size sinter layers and smaller micropore-size sinter layers, by alternatively laminating two types of preforms, each having a different density.