Method for preparing ruthenium oxide coating on inner wall of tantalum shell of electrolytic capacitor

TLDR: In this paper, a method for preparing ruthenium oxide coating on the inner wall of a tantalum shell of an electrolytic capacitor, belonging to capacitor cathode preparation methods, is presented.

Abstract: The invention discloses a method for preparing a ruthenium oxide coating on the inner wall of a tantalum shell of an electrolytic capacitor, belonging to capacitor cathode preparation methods. The method comprises the following steps of: mixing a ruthenium compound and valve metal powder to a powder mixture, and mixing the powder mixture and a solvent to obtain a slurry; evenly applying the slurry onto the inner wall of the tantalum shell, and drying; putting the dried tantalum shell into a coating furnace, and introducing steam to carry out thermal decomposition; dissolving ruthenium halide into deionized water to obtain an electrolyte, and adding additives to adjust the pH value to 1-5; and injecting the electrolyte into the tantalum shell, introducing a direct current, of which the current density is 5-50mA/cm , to carry out electroplating for 10-30 minutes, putting the electroplated tantalum shell into the coating furnace, and introducing steam to carry out heat treatment for 1-3 hours. The electrolytic capacitor cathode made by the method disclosed by the invention can increase the capacitance of the liquid tantalum capacitor with the same volume by more than one time, and the equivalent series resistance is smaller; and thus, the invention provides a method for preparing an electrolytic capacitor cathode.