METHOD FOR PRODUCING CATHODE FOIL AND ELECTROLYTIC CAPACITOR CATHODE FOIL Russian patent published in 2007 - IPC H01G9/58 H01G9/45 

FIELD: electrical engineering; cathode foil for electrolytic capacitors and method for its manufacture.

SUBSTANCE: proposed method for producing cathode foil includes covering of both sides of aluminum base with porous titanium-nitride layer in vacuum chamber by way of electron-beam evaporation while continuously stirring aluminum base above evaporator at distance of 340-700 mm and maintaining pressure of 0.08-0.2 Pa within chamber in nitrogen environment. Titanium nitride evaporates while nitrogen is jointly supplied from two evaporators at constant nitrogen feed of (15 - 30)x10^-6 m³/s to condensation zone and its regulated feed into vacuum chamber. Dip angle of steam flow is 68 to 78 deg. Flow changes its direction twice while passing condensation zone. Condensation temperature is maintained between 200 and 550°C. Evaporators can be disposed symmetrically to center line of aluminum base and spaced 220 to 300 mm apart. Cathode foil has aluminum base, 10-30 μm thick, covered on both sides with titanium nitride layer incorporating pore-separated crystallite grains and blocks. Titanium nitride layer thickness is 0.5-6.0 μm; crystallite grains and blocks have granular structure and elongated perpendicular to aluminum base surface. Total porosity of titanium nitride is 30-60% and open porosity, 20-40%; titanium nitride equilibrium structure content in condensate volume amounts to 80%. Cathode foil electrostatic capacity ranges between 899 and 5000 μF/cm².

EFFECT: enlarged surface area of foil contacting capacitor electrolyte, enhanced corrosion resistance in electrolyte, minimized resistance at cathode-to-electrolyte transition.

12 cl, 6 dwg