Claims
- 1. A tantalum powder, wherein said tantalum powder has a BET surface area of at least 1.5 m2/g, and wherein when said tantalum powder is formed into an electrolytic capacitor anode, said anode has a capacitance of at least about 190,000 CV/g, when formed at a Vf of 20 V and sintered at 1400° C. for 10 minutes.
- 2. The tantalum powder of claim 1, wherein said tantalum powder is flaked, nodular, angular, or combinations thereof.
- 3. The tantalum powder of claim 1, wherein said anode has a capacitance of from about 190,000 to about 285,000 CV/g.
- 4. The tantalum powder of claim 1, wherein said tantalum powder has a BET surface area of from about 1.5 to about 8 m2/g.
- 5. The tantalum powder of claim 1, wherein said tantalum powder has a BET surface area of from about 1.7 to about 5 m2/g.
- 6. The tantalum powder of claim 1, wherein said tantalum powder has a BET surface area of at least 5 m2/g, and wherein said anode has a capacitance of from about 200,000 to about 285,000 CV/g.
- 7. A capacitor anode comprising the tantalum powder of claim 1.
- 8. The capacitor anode of claim 7, wherein said tantalum powder is sintered at a temperature of from about 1200 to about 1750° C.
- 9. The capacitor anode of claim 7, wherein said anode has a DC leakage of less than about 5.0 na/CV.
- 10. The capacitor anode of claim 7, wherein said anode has a DC leakage of from about 0.5 to about 2 na/CV.
- 11. A capacitor anode comprising the tantalum powder of claim 3.
- 12. The capacitor anode of claim 11, wherein said tantalum powder is sintered at a temperature of from about 1200 to about 1750° C.
- 13. The capacitor anode of claim 11, wherein said anode has a DC leakage of less than about 5.0 na/CV.
- 14. The capacitor anode of claim 11, wherein said anode has a DC leakage of from about 0.5 to about 2.0 na/CV.
- 15. A capacitor anode comprising the tantalum powder of claim 4.
- 16. The capacitor anode of claim 15, wherein said tantalum powder is sintered at a temperature of from about 1200 to about 1750° C.
- 17. The capacitor anode of claim 15, wherein said anode has a DC leakage of less than about 5.0 na/CV.
- 18. The capacitor anode of claim 15, wherein said anode has a DC leakage of from about 0.5 to about 2.0 na/CV.
- 19. A capacitor anode comprising the tantalum powder of claim 5.
- 20. The capacitor anode of claim 19, wherein said tantalum powder is sintered at a temperature of from about 1200 to about 1750° C.
- 21. The capacitor anode of claim 19, wherein said anode has a DC leakage of less than about 5.0 na/CV.
- 22. The capacitor anode of claim 19, wherein said anode has a DC leakage of from about 0.5 to about 2.0 na/CV.
- 23. A method of making a tantalum powder, comprising milling a starting powder in a fluid and optionally a milling media using a high energy mill to form a tantalum powder having a BET surface area of at least about 1.5 m2/g.
- 24. The method of claim 23, wherein said high energy mill comprises a planetary ball mill, a spinning air flow jet mill, or an opposed jet fluid energy mill.
- 25. The method of claim 23, wherein said milling is planetary ball milling.
- 26. The method of claim 23, wherein said milling media comprises stainless steel balls.
- 27. The method of claim 23, wherein said BET surface area is at least 3 m2/g.
- 28. The method of claim 23, wherein said BET surface area is at least 5 m2/g.
- 29. The method of claim 23, wherein said BET surface area is from about 1.7 to about 8 m2/g.
- 30. The method of claim 23, wherein said tantalum powder is flaked, nodular, angular, or any combinations thereof.
- 31. The method of claim 23, wherein said fluid comprises a surfactant.
- 32. The method of claim 23, wherein said fluid comprises methanol.
- 33. The method of claim 23, wherein said mill imparts a force of from about 0.3 G to about 25 G to said milling media.
- 34. The method of claim 23, wherein said mill imparts a force of at least 0.5 G to said milling media.
- 35. The method of claim 23, wherein said milling occurs for a time of from about 30 minutes to 10 hours.
- 36. The method of claim 23, wherein said milling occurs for a time of about 8 hours or less.
- 37. The method of claim 23, wherein said high energy mill comprises a centrifugal mill.
- 38. The method of claim 23, wherein a ratio of the volume of said fluid to the combined volume of said starting powder and said milling media is from about 0.5:1 to about 3:1.
- 39. The method of claim 23, wherein a ratio of the volume of said fluid to the combined volume of said starting powder and said milling media is from about 0.5:1 to about 2:1.
- 40. The method of claim 23, wherein a ratio of the volume of said fluid to the combined volume of said starting powder and said milling media is from about 0.5:1 to about 1:1.
- 41. The method of claim 23, further comprising removing said fluid from tantalum powder.
- 42. The method of claim 41, wherein said removing comprises evaporating, heating, filtering, or combinations thereof.
- 43. A method of making a valve metal powder, comprising milling a starting powder in a fluid and optionally a milling media using a high energy mill to form a valve metal powder having a BET surface area of at least about 1.5 m2/g.
- 44. The method of claim 43, wherein said valve metal powder is niobium.
- 45. A valve metal powder produced by the method of claim 43.
- 46. The method of claim 23, wherein said milling is opposed jet fluid energy milling.
- 47. The method of claim 23, wherein said milling occurs for a time of from about 2 to about 3 hours.
- 48. The method of claim 23, wherein said milling media is present.
- 49. The method of claim 43, wherein said milling media is present.
- 50. The method of claim 23, wherein said fluid is a gas or liquid.
- 51. The method of claim 43, wherein said fluid is a gas or liquid.
- 52. The method of claim 23, wherein said milling is fluid energy milling
- 53. The method of claim 43, wherein said milling is fluid energy milling.
- 54. The method of claim 43, wherein said milling is opposed jet fluid energy milling.
Parent Case Info
[0001] This application claims priority under 35 U.S.C. §119(e) of prior U.S. Provisional Patent Application No. 60/477,418 filed Jun. 10, 2003, which is incorporated in its entirety by reference herein.
Provisional Applications (1)
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Number |
Date |
Country |
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60477418 |
Jun 2003 |
US |