TH73444A - The lead wire used to make a capacitor has increased pull resistance and strength. - Google Patents

Abstract

DC60 (02/04/46) The wire used to make capacitors is made from a powdered metal alloy containing at least niobium and silicon, with niobium being the highest percentage metal present in the niobium wire. The wire has a tensile strength, controlled at the final diameter, that is greater than that of capacitor wire made from solid metal alloys. Therefore, powdered metal alloy wire is harder than solid metal alloy capacitor wire in terms of leakage current. This is for use with tantalum, niobium, or niobium-zirconium lead capacitors, which are fired at temperatures of approximately 1150°C and above. The wire used to make capacitors is made from a powdered metal alloy containing at least niobium and silicon, with niobium being the highest percentage metal present in the niobium wire. The wire has a tensile strength, controlled at the final diameter, that is greater than that of capacitor wire made from solid metal alloys. Therefore, powdered metal alloy wire is harder. More than the wire used to make capacitors, which is obtained from alloying metal ingots with specified electrical leakage, for use with tantalum, niobium, or niobium-zirconium lead wires used in capacitors at firing temperatures of approximately 1150°C and higher.

Claims (18)

1. The process for making silicon-bonded niobium lead wire for use in capacitors involves: (a) the formation of a low-oxygen niobium powder by hydrogen wetting of a niobium bar and grinding the bar to achieve a Fisher's average particle size range smaller than approximately 150 microns; (b) the drying of the powder using hydrogen, and sometimes deoxidation; (c) the mixing of the low-oxygen niobium powder with silicon filler powder and cold compression to form bars; (d) the mechanical heating of the bar to form rods; and (e) the rods are then coiled and stretched using cold compression to form silicon-bonded wire. 2. The procedure for claim 1, where silicon is doped at a concentration of less than 600 parts per million. 3. The procedure for claim 1, where silicon is doped at a rate of 150 to 600 parts per million. 4. Procedure of Claim 1, where long bars are subjected to dimensional reduction and intermediate softening involving the following softening, rolling, sintering, dimensional reduction and drawing steps. 5. Procedure of Claim 1, where the bar is subjected to various stages which include (i) first softening combustion, (ii) rolling, (iii) second softening combustion, (iv) dimensional reduction and (v) drawing. 6. Procedure of Claim 5, whereby the reduction and intermediate heating schedule involves the following steps: heating at approximately 2500°F for 1.5 hours, winding to a diameter of approximately 0.440 inches; heating at approximately 2500°F for 1.5 hours; reducing the diameter to approximately 0.1 inches; stretching into a wire with a diameter of at least approximately 0.005 inches. 7. Procedure of Claim 1, whereby the wire contains additional metallic alloys selected from a group comprising tantalum, zirconium, titanium and their alloys. 8. The procedure for Claim 1, whereby the niobium powder has an oxygen content of approximately 400 parts per million. 9. The procedure for Claim 1 is such that the wire has a greater tensile strength than the niobium wire used in capacitors and the niobium-zirconium alloy obtained directly from ingot alloying. 10. Capacitor wires with a higher tensile strength than niobium wire and niobium-zirconium alloys are directly obtained from ingot casting. The wire is produced using a process that includes: (a) the formation of low-oxygen niobium powder by hydrogen wetting of the niobium ingot and grinding the ingot to achieve a Fisher average particle size range smaller than approximately 150 microns; (b) hydrogen drying and sometimes deoxidation of the powder; (c) mixing of the low-oxygen niobium powder with silicon filler powder and cold compression to form ingots; (d) mechanical heating of the ingot to form a long rod; and (e) cold winding and stretching of the long rod to form silicon-containing wire. 11. The wire used to make the capacitors of claim 10, where silicon is doped at a concentration of less than 600 parts per million. 12. The wire used to make the capacitors of claim 10, where silicon is doped in the range of 150 to 300 parts per million. 13. The wire used in the capacitor of claim 10, where the long rod is reduced in size and softened by sintering, involves the steps of softening, rolling, sintering, reducing and drawing. 14. The wire used to make the capacitor of claim 10, where the long rod is subjected to various processes which include (i) the first softening step, (ii) the rolling step, (iii) the second softening step, (iv) the sizing step and (v) the drawing step. 15. The wire used for the capacitors of claim 14, where the reduction and intermediate heating schedule involves the following steps: heating at approximately 2500°F for 1.5 hours; winding to a diameter of approximately 0.440 inches; heating at approximately 2500°F for 1.5 hours; reducing the diameter to approximately 0.1 inches; stretching into a wire with a diameter of at least approximately 0.005 inches. 16. The wire used to make the capacitors of claim 10, where the wire contains additional metallic alloys selected from a group consisting of tantalum, zirconium, titanium and their alloys. 17. The wire used to make the capacitors in claim 10, where the niobium powder has an oxygen content of less than approximately 400 parts per million. 18. The wire used to make the capacitors under claim 10 has a higher tensile strength than the niobium wire used to make capacitors and the niobium-zirconium alloy obtained directly from alloying ingots.