Coil component
A coil component includes a magnetic portion that includes metal particles and a resin material, a coil conductor embedded in the magnetic portion, and outer electrodes electrically connected to the coil conductor. The average particle diameter of the metal particles in the magnetic portion is 1 μm or more and 5 μm or less, and the CV value of the metal particles is 50% or more and 90% or less.
1. A coil component comprising:
a magnetic portion that includes metal particles and a resin material;
a coil conductor embedded in the magnetic portion; and
outer electrodes electrically connected to the coil conductor,
wherein an average particle diameter of the metal particles in the magnetic portion is from 1 to 5 μm, and a CV value of the metal particles is from 50% to 90%,
the magnetic portion includes a magnetic base and a magnetic outer coating,
the magnetic portion has a portion located in a core portion of the coil conductor and includes the metal particles and the resin material,
a metal material constituting the metal particles comprises at least one selected from iron, Fe—Si alloys, Fe—Si—Cr alloys, and Fe—Si—Al alloys,
a protective layer containing Ti and resin is disposed on the magnetic portion,
a filling factor of the metal particles in the magnetic base is 65% or more, and a filling factor of the metal particles in the magnetic outer coating is 50% or more,
the coil conductor is wound in α-winding form,
a length of the coil component is about 0.9 mm or more and 2.2 mm or less, and
a width of the coil component is about 0.6 mm or more and 1.8 mm or less.
2. The coil component according to claim 1 , wherein the average particle diameter is from 1 to 3 μm.
3. The coil component according to claim 1 , wherein the CV value is from 70% to 90%.
4. The coil component according to claim 1 , wherein the metal particles are a mixture of amorphous particles and crystalline particles.
5. The coil component according to claim 1 , wherein the amorphous particles are particles of an Fe—Si—Cr alloy, and the crystalline particles are particles of iron.
6. The coil component according to claim 1 , wherein the metal particles are a mixture of nanocrystal particles and crystalline particles.
7. The coil component according to claim 1 , wherein the crystalline particles are particles of hard grade carbonyl iron having an onion skin structure.
8. The coil component according to claim 1 , wherein end portions of the coil conductor extend to a bottom surface of the magnetic portion, and the outer electrodes are disposed on a bottom surface of the coil component.
9. The coil component according to claim 1 , wherein:
the CV value of the metal particles is from 70% to 90%;
the metal particles are a mixture of amorphous particles and crystalline particles; and
an average particle diameter of the amorphous particles is greater than an average particle diameter of the crystalline particles;
the amorphous particles are coated with first insulating coating films containing phosphoric acid, and the crystalline particles are coated with second insulating films containing Si;
an average thickness of the first insulating coating films is larger than an average thickness of the second insulating coating films; and
the average thickness of the first insulating coating films is from 10 to 30 nm, and the average thickness of the second insulating coating films is from 5 to 20 nm.
10. The coil component according to claim 1 , wherein:
end portions of the coil conductor extend to a bottom surface of the magnetic base, and each of the outer electrodes is electrically connected to a respective one of the end portions.
11. The coil component according to claim 1 , wherein:
the magnetic base has grooves; and
end portions of the coil conductor extend into the grooves.
12. The coil component according to claim 1 , wherein:
the length of the coil component is about 0.9 mm or more and 1.8 mm or less, and
the width of the coil component is about 0.6 mm or more and 1.0 mm or less.
13. The coil component according to claim 1 , wherein:
the magnetic base includes a base portion and a protrusion portion disposed on an upper surface of the base portion, and
edge portions at a periphery of an upper surface of the base portion are higher in a thickness direction than a portion where an edge of the protrusion portion contacts the upper surface of the base portion.
14. The coil component according to claim 1 , wherein the metal particles are coated with an insulating material.
15. The coil component according to claim 14 , wherein the metal particles are a mixture of amorphous particles or nanocrystal particles and crystalline particles, and a thickness of an insulating coating film of the amorphous particles or nanocrystal particles is larger than a thickness of an insulating coating film of the crystalline particles.
16. The coil component according to claim 15 , wherein the thickness of the insulating coating film of the amorphous particles or nanocrystal particles is from 10 to 30 nm, and the thickness of the insulating coating film of the crystalline particles is from 5 to 20 nm.
17. The coil component according to claim 15 ,
wherein the amorphous particles are particles of an Fe—Si—Cr alloy and the crystalline particles are particles of iron; and
the particles of an Fe—Si—Cr alloy are coated with an insulating material containing phosphoric acid, and the particles of iron are coated with an insulating material containing Si.
18. The coil component according to claim 1 , wherein:
the metal particles are a mixture of amorphous particles or nanocrystal particles and crystalline particles, and a thickness of an insulating coating film of the amorphous particles or nanocrystal particles is larger than a thickness of an insulating coating film of the crystalline particles.
19. The coil component according to claim 18 , wherein the thickness of the insulating coating film of the amorphous particles or nanocrystal particles is from 10 nm to 30 nm, and the thickness of the insulating coating film of the crystalline particles is from 5 nm to 20 nm.