Inductive component and method for producing the same
The invention relates to an inductive component ( 10 ) whose soft-magnetic core ( 11 ) consists of a powder composite. Said powder composite is produced by mixing a ferromagnetic amorphous or nanocrystalline alloy powder with a ferromagnetic dielectric powder and a thermoplastic or duroplastic polymer. Unlike conventional injection-molded or cast soft-magnetic cores, cores from a composite comprising a dielectric ferromagnetic powder allow for packing densities of substantially more than 55% by volume.
1. An inductive component comprising:
(1) at least one winding; and
(2) a soft magnetic core molded about the at least one winding, the soft magnetic core being made of a ferromagnetic powder composite, the ferromagnetic powder composite comprising:
a. a ferromagnetic alloy powder, comprising:
(i) amorphous or nanocrystalline alloy particles that are surface-oxidized; and
(ii) a ferromagnetic dielectric powder, and
b. a cured resin resulting from curing a pourable casting resin formulation that has been poured into a mold about the at least one winding.
2. Inductive component according to claim 1 , wherein the ferromagnetic dielectric powder comprises an inorganic ferromagnetic powder.
3. Inductive component according to claim 2 , wherein the inorganic ferromagnetic powder comprises a ferrite powder.
4. Inductive component according to claim 1 , wherein the ferromagnetic dielectric powder comprises a surface-insulated metallic powder.
5. Inductive component according to claim 4 , wherein the surface-insulated metallic powder comprises a ferromagnetic metal carbonyl powder or a mixture of ferromagnetic metal carbonyl powders.
6. Inductive component according to claim 5 , wherein the ferromagnetic metal carbonyl powder comprises iron carbonyl powder or nickel carbonyl powder or cobalt carbonyl powder or mixtures thereof.
7. Inductive component according to one of claim 1 , wherein the ferromagnetic dielectric powder is composed of powder particles with an average powder particle size <10 μm.
8. Inductive component according to claim 7 , wherein the ferromagnetic dielectric powder is composed of powder particles with an average powder particle size <5 μm.
9. Inductive component according to claim 1 , wherein the surface-oxidized amorphous or nanocrystalline alloy particles have an average particle size <2 μm.
10. Inductive component according to claim 9 , wherein the surface-oxidized amorphous or nanocrystalline alloy particles have a dimension that averages between 0.04 mm and 0.5 mm.
11. Inductive component according to claim 1 wherein the surface-oxidized amorphous or nanocrystalline alloy particles are coated with a plastic.
12. Inductive component according to claim 11 , wherein the plastic comprises a silane.
13. Inductive component according to claim 1 , wherein the ferromagnetic powder composite has a saturation magnetization B s >0.5 Tesla and a permeability 10≦μ≦200.
14. Inductive component according to claim 1 , wherein the casting resin formulation comprises a monomeric or oligomeric resin from which a polyamide, a polyacrylate, or a polybutylene terephthalate resin is formed.
15. Inductive component according to claim 1 , wherein the inductive component further comprises a housing.
16. Inductive component according to claim 1 , wherein the ferromagnetic alloy powder and the pourable casting resin formulation are mixed prior to being molded about the at least one winding.
17. Inductive component according to claim 1 in which (a) the at least one winding defines a central space and (b) at least a portion of the soft magnetic core is molded into the central space.
18. Inductive component according to claim 1 , wherein the ferromagnetic alloy powder comprises nanocrystalline alloy particles that are surface-oxidized.
19. An inductive component comprising:
(i) a mold comprising at least one winding; and
(ii) a soft magnetic core comprising a ferromagnetic powder composite comprising a mixture of:
a. a ferromagnetic alloy powder comprising:
(1) amorphous or nanocrystalline alloy particles that are surface-oxidized, and
(2) a ferromagnetic dielectric powder; and
b. a cured resin formed by curing a pourable casting resin formulation poured into the mold.
20. An inductive component comprising:
(1) at least one winding; and
(2) a soft magnetic core molded about the at least one winding, the soft magnetic core being made of a ferromagnetic powder composite, the ferromagnetic powder composite comprising:
a. a ferromagnetic alloy powder, comprising:
(i) amorphous or nanocrystalline alloy particles that are surface-oxidized and have an average particle size <2 mm, a thickness from 0.01 to 0.04 mm, and sizes in the other two dimensions from 0.04 to 1.0 mm; and
(ii) a ferromagnetic dielectric powder, selected from ferrite powder and one or more ferromagnetic metal carbonyl powders, each having an average particle size <10 μm, and
b. a cured polyamide, polyacrylate, or polybutylene terephthalate resin resulting from curing a pourable casting resin formulation that has been poured into a mold about the at least one winding.