Claims
- 1. A method of providing dielectric isolation between adjacent metal layers of a laminated magnetic assembly, comprising:
providing a laminated magnetic assembly having a plurality of layers, wherein the plurality of layers are formed in part of iron; and oxidizing the plurality of layers to produce a coating comprising a mixture of iron oxides, the resulting magnetic assembly having a resistivity of greater than about 60 ohm-cm.
- 2. The method of claim 1, wherein the oxidizing step comprises exposing the plurality of layers to steam in the presence of oxygen at a temperature of at least 500° F.
- 3. The method of claim 2, further comprising adjusting the pH of the feedwater of the steam to above pH 7.
- 4. The method of claim 3, wherein the pH is adjusted to from about 8 to about 11.
- 5. The method of claim 3, wherein the pH is adjusted by contacting the feedwater and a salt.
- 6. The method of claim 5, wherein in solution the salt forms a hydrate of its associated ion.
- 7. The method of claim 5, wherein the salt is selected from the group consisting of calcium oxide, calcium hydroxide, calcium carbonate, magnesium oxide, magnesium hydroxide, and magnesium carbonate.
- 8. The method of claim 4, wherein the pH is adjusted by contacting the feedwater and a salt.
- 9. The method of claim 8, wherein in solution the salt forms a hydrate of its associated ion.
- 10. The method of claim 8, wherein the salt is selected from the group consisting of calcium oxide, calcium hydroxide, calcium carbonate, magnesium oxide, magnesium hydroxide, and magnesium carbonate.
- 11. The method of claim 2, wherein the plurality of layers are heated to a temperature of from about 500° F. to 740° F.
- 12. The method of claim 11, wherein the plurality of layers are an amorphous metal alloy and the layers are heated to between about 670° F. and 695° F.
- 13. The method of claim 1, wherein the laminated magnetic assembly is a wound core.
- 14. The method of claim 1, wherein the laminated magnetic assembly comprises stacked metal layers.
- 15. The method of claim 2, wherein the oxidized laminated magnetic assembly exhibits at least a 15% decrease in power loss at operational frequencies of 10 to 20 kHz in comparison to the magnetic assembly prior to exposure to steam and air.
- 16. A method of making a dielectrically insulated soft magnetic assembly, comprising:
winding an amorphous metal alloy ribbon containing iron into a multi-layered core; and heating the core in the presence of water and oxygen to oxidize the iron of amorphous metal alloy ribbon to form a coating comprising oxides of iron which is at least about 0.03 microns thick.
- 17. A method of forming an insulative coating on the surface of an amorphous metal alloy strip, comprising:
providing an amorphous metal alloy strip in which the percentage of iron exceeds the percentage of any other element present in the alloy; heating the strip to a temperature at which the alloy anneals; and exposing the strip to steam in the presence of oxygen to form a coating of oxides of iron over a substantial portion of the strip.
- 18. The method of claim 17, further comprising winding the strip into a core prior to heating the strip to the annealing temperature.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. application Ser. No. 09/315,549, filed May 20, 1999, which is hereby incorporated herein by reference.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09315549 |
May 1999 |
US |
Child |
10424966 |
Apr 2003 |
US |