Nitrided niobium powders and niobium electrolytic capacitors
View Patent ↗A nitrogen containing niobium powder is disclosed as well as electrolytic capacitors formed from the niobium powders. Methods to reduce DC leakage in a niobium anode are also disclosed.
1. Niobium powder having a nitrogen content of at least about 300 ppm and BET surface area of at least 0.62 m 2 /g, wherein said niobium powder has a flow of at least about 1 mg/s.
2. The niobium powder of claim 1 , wherein said nitrogen content is at least about 400 ppm.
3. The niobium powder of claim 1 , wherein said nitrogen content is at least about 500 ppm.
4. The niobium powder of claim 1 , wherein said nitrogen content is from about 300 to about 5,000 ppm.
5. The niobium powder of claim 1 , wherein said nitrogen content is from about 500 ppm to about 4,000 ppm.
6. The niobium powder of claim 1 , wherein said nitrogen content is from about 500 ppm to about 3,500 ppm.
7. The niobium powder of claim 1 , wherein said nitrogen content is from about 500 ppm to about 3,000 ppm.
8. The niobium powder of claim 1 , wherein said nitrogen content is from about 1,500 ppm to about 5,000 ppm.
9. The niobium powder of claim 1 , wherein when said powder is formed into an electrolytic capacitor anode, said anode has a DC leakage which is less than an electrolytic capacitor anode formed from niobium powder having substantially no nitrogen.
10. The niobium powder of claim 9 , wherein the DC leakage is decreased about 50% or less compared to the electrolytic capacitor anode formed from niobium powder having substantially no nitrogen.
11. The niobium powder of claim 9 , wherein the DC leakage is decreased about 25% or less compared to the electrolytic capacitor anode formed from niobium powder having substantially no nitrogen.
12. The niobium powder of claim 1 , wherein said niobium powder comprises flaked niobium powder.
13. The niobium powder of claim 1 , wherein said powder has a BET surface area of at least 0.8 m 2 /g.
14. The niobium powder of claim 1 , wherein said powder has a BET surface area of from about 0.62 to about 5.0 m 2 /g.
15. The niobium powder of claim 1 , wherein said powder has a BET surface area of from about 0.8 to about 5.0 m 2 /g.
16. The niobium powder of claim 12 , wherein said powder has a Scott Density of less than about 35 g/in 3 .
17. The niobium powder of claim 1 , wherein when said powder is formed into an electrolytic capacitor anode, said anode has a capacitance of from about 30,000 CV/g to about 61,000 CV/g.
18. The niobium powder of claim 1 , wherein said niobium powder comprises nodular, flaked, angular niobium powder, or combinations thereof.
19. A capacitor anode prepared from a formulation comprising the niobium powder of claim 1 .
20. The capacitor of claim 19 , wherein said powder is sintered at a temperature of from about 1200° C. to about 1750° C.
21. A capacitor comprising a capacitor anode, wherein said capacitor anode comprises the niobium powder of claim 1 .
22. The niobium powder of claim 1 , having a phosphorus level of less than about 400 ppm.
23. The capacitor of claim 19 , wherein said capacitor is formed at a voltage of about 50 volts or less.
24. The capacitor of claim 19 , wherein said capacitor has a DC leakage of less than about 5.0 na/CV.
25. The capacitor of claim 19 , wherein said capacitor has a DC leakage of from about 5.0 na/CV to about 0.50 na/CV.
26. A capacitor anode comprising the niobium powder of claim 1 .
27. A capacitor anode comprising niobium powder having a nitrogen content of at least about 300 ppm and a flow of at least about 1 mg/s, wherein said anode has a working voltage of from about 4 to about 16 volts.
28. The capacitor anode of claim 27 , wherin said nitrogen content is from about 300 to about 5,000 ppm.
29. The capacitor anode of claim 27 , wherein said nitrogen content is from about 1,500 ppm to about 5,000 ppm.
30. The niobium powder of claim 1 , further comprising an oxygen content of at least about 2,000 ppm oxygen.
31. The niobium powder of claim 1 , wherein said niobium powder is doped with oxygen.
32. The capacitor anode of claim 27 , wherein said niobium powder is doped with oxygen.
33. Nitrided niobium powder having a BET surface area of at least 0.62 m 2 /g and a flow of at least about 1 mg/s.
34. The nitrided niobium powder of claim 33 having a BET surface area of from 0.62 m 2 /g to 5.0 m 2 /g.
35. The nitrided niobium powder of claim 33 having a BET surface area of 0.8 m 2 /g to 5.0 m 2 /g.
36. The nitrided niobium powder of claim 33 having a BET surface arcs of at least 1.0 m 2 /g.
37. The nitrided niobium powder of claim 33 having a BET surface area of from about 1.0 m 2 /g to about 5.0 m 2 /g.
38. A capacitor anode comprising the nitrided niobium powder of claim 33 .
39. A capacitor anode comprising the nitrided niobium powder of claim 34 .
40. A capacitor anode comprising the nitrided niobium powder of claim 35 .
41. A capacitor anode comprising the nitrided niobium powder of claim 36 .
42. A capacitor anode comprising the nitrided niobium powder of claim 37 .
43. The niobium powder of claim 1 , wherein said flow is at least about 19 mg/s.
44. The niobium powder of claim 1 , wherein said flow is from about 80 to about 500 mg/s.
45. The niobium powder of claim 1 , wherein said niobium powder has a particle size of from about 10 to about 300 microns or more.
46. The niobium powder of claim 1 , wherein said niobium powder comprises agglomerated powder.
47. The niobium powder of claim 46 , wherein said agglomerated powder has a particle size of about 300 microns or less.
48. The capacitor anode of claim 27 , wherein said flow is from about 19 to about 500 mg/s.
49. The capacitor anode of claim 27 , wherein said niobium powder comprises agglomerated powder.
50. The nitrided niobium powder of claim 33 , wherein said flow is from about 19 to about 500 mg/s.
51. The nitrided niobium powder of claim 33 , wherein said nitrided niobium powder comprises agglomerated powder.