Anodes containing spherical powder and capacitors
Anodes made from powder, such as tantalum powder, that is highly spherical is described. Methods to make the anodes are further described.
1. A capacitor anode comprising a powder that is pressed and sintered, wherein said powder comprises a spherical powder that is a metal or metal sub-oxide or both, said spherical powder comprising
a. a spherical shape wherein the powder has an average aspect ratio of from 1.0 to 1.4;
b. a purity of at least 99.5 wt %;
c. an average particle size of from about 0.5 micron to about 250 microns;
d. an apparent density from about 1.5 g/cc to about 15.5 g/cc;
e. a true density that is within +−3% of the metal or metal sub-oxide; and
f. a Hall flow rate of 40 sec or less,
wherein said powder is selected from niobium, tantalum, conductive niobium sub-oxide, or any combination thereof.
2. A metal or metal sub-oxide powder comprising
a. a spherical shape wherein the powder has an average aspect ratio of from 1.0 to 1.4;
b. a purity of at least 99.5 wt % based on total weight of said powder, excluding gas impurities;
c. an average particle size of from about 0.5 micron to about 250 microns;
d. an apparent density from about 1.5 g/cc to about 15.5 g/cc;
e. a true density that is within +−3% of the metal or metal sub-oxide; and
f. a Hall flow rate of 40 sec or less, wherein said metal or metal sub-oxide powder is tantalum, niobium, silicon, titanium, chromium, nickel, copper, zinc, zirconium, molybdenum, silver, gold, tungsten, or rhenium or an alloy thereof.
3. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder is of the formula NbO x , wherein x is 0.7 to 1.2.
4. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder is NbO, NbO 1.1 , NbO 0.8 , NbO 0.9 .
5. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder is said alloy.
6. The metal or metal sub-oxide powder of claim 5 , wherein said alloy is Ta—Ti alloy or a Ta—Si alloy or Ta—W alloy or Ta—Mo alloy or Ta—Nb alloy.
7. The metal or metal sub-oxide powder of claim 5 , wherein said alloy is a Ta-metal alloy.
8. The metal or metal sub-oxide powder of claim 5 , wherein said alloy is a Ta—Nb—Ti alloy.
9. The metal or metal sub-oxide powder of claim 5 , wherein said alloy is a Ta-metal alloy wherein the Ta is present in the highest percent based on the weight of the alloy.
10. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder is doped with one or more dopants.
11. The metal or metal sub-oxide powder of claim 10 , wherein said one or more dopants is nitrogen, phosphorous, yittrium, or silica.
12. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder has one or more of the following properties:
a) said apparent density of from 4 g/cc to 12.3 g/cc,
b) a D10 particle size of from about 5 microns to about 25 microns,
c) a D50 particle size of from about 20 microns to about 50 microns,
d) a D90 particle size of from about 30 microns to about 100 microns, and/or
e) a BET surface area of from about 0.05 m 2 /g to about 20 m 2 /g.
13. The metal or metal sub-oxide powder of claim 12 , wherein two or more of said one or more properties are present.
14. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder has one or more of the following properties:
a) an apparent density of from about 9 g/cc to about 12.3 g/cc,
b) a D10 particle size of from about 12 microns to about 25 microns,
c) a D50 particle size of from about 20 microns to about 40 microns,
d) a D90 particle size of from about 30 microns to about 70 microns, and/or
e) a BET surface area of from about 0.1 m 2 /g to about 15 m 2 /g.
15. The metal or metal sub-oxide powder of claim 12 , wherein said metal or metal sub-oxide powder has all of said one or more of the properties.
16. The metal or metal sub-oxide powder of claim 14 , wherein said metal or metal sub-oxide powder has all of said one or more of the properties.
17. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder has an oxygen level of less than 15,000 ppm.
18. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder has an oxygen level of from 20 ppm to 250 ppm.
19. The metal or metal sub-oxide powder of claim 2 , wherein said average aspect ratio is from 1.0 to 1.1.
20. The metal or metal sub-oxide powder of claim 2 , wherein said average aspect ratio is from 1.0 to 1.05.
21. The metal or metal sub-oxide powder of claim 2 , wherein said average particle size is from about 0.5 micron to about 10 microns.
22. The metal or metal sub-oxide powder of claim 2 , wherein said average particle size is from about 5 microns to about 25 microns.
23. The metal or metal sub-oxide powder of claim 2 , wherein said average particle size is from about 15 microns to about 45 microns.
24. The metal or metal sub-oxide powder of claim 2 , wherein said average particle size is from about 35 microns to about 75 microns.
25. The metal or metal sub-oxide powder of claim 2 , wherein said average particle size is from about 55 microns to about 150 microns.
26. The metal or metal sub-oxide powder of claim 2 , wherein said average particle size is from about 105 microns to about 250 microns.
27. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder has at least one of the following properties:
a. a D10 size of from about 5 microns to 25 microns;
b. a D90 size of from about 20 microns to 80 microns; or
c. oxygen between 100 ppm to 1000 ppm.
28. The metal or metal sub-oxide powder of claim 2 , wherein said apparent density is from about 4 g/cc to about 12.6 g/cc.
29. The metal or metal sub-oxide powder of claim 2 , wherein said apparent density is from about 4.5 g/cc to about 12 g/cc.
30. The metal or metal sub-oxide powder of claim 2 , wherein said apparent density is from about 5 g/cc to about 10 g/cc.
31. The metal or metal sub-oxide powder of claim 2 , wherein said apparent density is from about 6 g/cc to about 12.5 g/cc.
32. The metal or metal sub-oxide powder of claim 2 , wherein said true density is within 2% of said metal or metal sub-oxide.
33. The metal or metal sub-oxide powder of claim 2 , wherein said true density is within 1% of said metal or metal sub-oxide.
34. The metal or metal sub-oxide powder of claim 2 , wherein said Hall flow rate is 30 sec or less.
35. The metal or metal sub-oxide powder of claim 2 , wherein said Hall flow rate is 20 sec or less.
36. The metal or metal sub-oxide powder of claim 2 , wherein said Hall flow rate is from 4 to 40 sec.
37. The metal or metal sub-oxide powder of claim 2 , wherein said Hall flow rate is from 4 to 15 sec.
38. The metal or metal sub-oxide powder of claim 2 , wherein said average aspect ratio is from 1.0 to 1.1; said true density is within +−1% of the metal or metal sub-oxide; and said Hall flow rate is 20 sec or less.
39. The metal or metal sub-oxide powder of claim 2 , wherein said metal or metal sub-oxide powder comprises at least two different size fractions, wherein the size fraction is based on average particle size of the size fraction.
40. The metal or metal sub-oxide powder of claim 39 , wherein said metal or metal sub-oxide powder comprises a first size fraction having an average particle size from about 10 microns to about 25 microns, and a second size fraction of from about 26 microns to about 45 microns.
41. The metal or metal sub-oxide powder of claim 39 , wherein said metal or metal sub-oxide powder comprises a first size fraction of from about 0.5 micron to about 15 microns, and a second size fraction of from about 35 microns to about 75 microns.
42. A powder blend comprising a) a spherical powder that is the metal or metal sub-oxide powder of claim 2 and b) non-spherical powder selected from one or more non-spherical metal powders and/or non-spherical metal sub-oxide powders.
43. The powder blend of claim 42 , wherein the non-spherical powder is an angular powder, a flake powder, and/or a nodular powder, or any combinations thereof.
44. The powder blend of claim 42 , wherein the powder blend has from 25% to 75% by weight of the spherical powder and from 25% to 75% by weight of the non-spherical powder.
45. The powder blend of claim 42 , wherein the powder blend has from 50% to 99% by weight of the spherical powder and from 1% to 50% by weight of the non-spherical powder.
46. The powder blend of claim 42 , wherein the powder blend has from 75% to 99% by weight of the spherical powder and from 1% to 25% by weight of the non-spherical powder.
47. A metal or metal sub-oxide powder comprising
a. a spherical shape wherein the powder has an average aspect ratio of from 1.0 to 1.4;
b. a purity of at least 99.5 wt % based on total weight of said powder, excluding gas impurities;
c. an average particle size of from about 0.5 micron to about 250 microns;
d. an apparent density from about 1.5 g/cc to about 15.5 g/cc;
e. a true density that is within +−3% of the metal or metal sub-oxide; and
f. a Hall flow rate of 40 sec or less, wherein said metal or metal sub-oxide powder is a valve metal.