METHOD OF MANUFACTURING OF CATHODE PLATE OF TANTALUM CAPACITOR WITH POROUS ANODE Russian patent published in 2015 - IPC H01G9/42 C25D5/00 C25D5/34 

FIELD: electricity.

SUBSTANCE: method includes surface preparation of cathode plate prior to the coating application, this means sand blasting of both flat plate, and internal surface of capacitor body or creation on the internal surface of the capacitor body of the tantalum powder underlayer by application of the spirit suspension of the tantalum powder with further sintering in vacuum, etching in the nitric acid solution with further washing by the distilled water, and application of the ruthenic coating to the prepared surface. At that sand blasting is performed using the aluminium oxide or silicone carbide powder with grain size from 20 to 100 microns at air pressure 1.5-3.0 atm. Etching in the nitric acid solution is performed upon presence of the hydrofluoric acid or ammonium fluoride in amount 10-20%wt at temperature 25-30°C for 20-60 s. The ruthenic coating with thickness 0.5-5.0 micron is applied from the electrolyte containing 2-20 g/k of ruthenium in form of the ammonium salts of the binucleating complexes of nitridoaquachloride complex, for example (NH₄)₃[Ru₂(µ-N)(H₂O)₂Cl₈], 5-20 g/l of sulphuric acid, 10-20 g/l of ammate, under conditions of the electrolyte agitating at cathode current density 1.0-10.0 A/dm², temperature 40-60°C. then received metal ruthenic coating is subjected to the electrochemical anode oxidation in solution of 35-40% sulphuric, phosphoric, nitric or oxalic acid with holding under anode potential at voltage 10-100V and current 100-500mA for 5-20 minutes.

EFFECT: increased specific capacity of tantalum electrolyte capacitor with porous anode and achievement of stable work during operation in wide range of temperatures.

3 cl, 2 dwg, 8 tbl