CAPACITOR WITH FIBERED VALVE METAL ANODE

• US 3,740,834 A
• Filed: 11/15/1971
• Issued: 06/26/1973
• Est. Priority Date: 11/15/1971
• Status: Expired due to Term

• Current Assignee: Richard W. Douglass
• Original Assignee: Richard W. Douglass
• Inventors: Douglass, Richard W.
• Primary Examiner(s): Huckert, John W.
• Assistant Examiner(s): Larkin, William D.
• Application Number:
  US05/199,065
• Time in Patent Office: 589 Days
• Field of Search: 29/420.5,570,419,182,192 311/230 75/204
• US Class Current: 29/25.03
• CPC Class Codes: B22F 3/002 Manufacture of articles essentially made from metallic fibres
• CPC Class Codes: H01G 9/052 Sintered electrodes
• CPC Class Codes: Y10S 428/929 Electrical contact feature
• CPC Class Codes: Y10T 29/49801 Shaping fiber or fibered material
• CPC Class Codes: Y10T 29/49812 Temporary protective coating, impregnation, or cast layer
• CPC Class Codes: Y10T 428/12424 Mass of only fibers

Abstract

Capacitor anodes are produced in situ by sintering a powdered valve metal into a porous compact, impregnating the compact with another material in fluid or soft form which fills the pores of the compact, solidifying or hardening the second material and working the compact through the application of compressive forces to elongate it to thereby fiber the powders of the compact and to fiber the impregnant. The thus produced fiber compact is leached to remove the impregnant materials, to produce a bundle of interconnected fibers with an interconnected pore structure which can be filled with anodizing medium and later with electrolyte to comprise the capacitor. Alternatively, the impregnant can be the valve metal and the original compact can be removed after elongation and fibering.

Claims

2. The method of claim 1 wherein impregnant is the material removed.

3. The method of claim 1 wherein the porous compact is made of bonded powders selected from the group consisting of tantalum, niobium and their valve metal alloys.

4. The method of claim 3 wherein the powder compacting comprises sintering and wherein the impregnant is copper metal applied by vacuum impregnation.

5. The method of claim 1 wherein the compact is heated for compacting and cleaning and wherein the porous fiber bundle is heated for cleaning to a lower temperature than the compact heating temperature.

6. The method of claim 1 wherein the porous compact is made of bonded powders of a valve metal having a Fisher Average Particle Diameter of about 3-10 microns and the reduction ration is selected to produce fibers of a diameter at least one-third the particle diameter, as determined by the ratio of impregnated compact diameter before and after working.

7. The method of claim 1 wherein the porous compact is made of bonded powders of a valve metal having 0 to 25 percent of -325 mesh size powders and the remainder of larger size.

8. The method of claim 1 wherein the compact is made of bonded powders of the valve metal and compacted to a density between 25 and 65 percent of theoretical.

9. The method of claim 1 wherein the elongated porous fiber bundle is cut to short lengths to serve as individual anodes.

10. The method of claim 1 wherein a length section of the fiber bundle is collapsed to form a solid lead wire integral with the porous bundle.

11. The method of claim 1 further comprising the additional steps of anodizing the interior surfaces of pores within the porous fiber bundle, impregnating said pores with an electrolyte, and applying a counter-electorde to said electroltye to complete the formation of a capacitor.