Soft magnetic powder, magnetic core, and electronic component
A soft magnetic powder capable of maintaining high insulation resistance even after exposure to a high-temperature environment, a dust core, and an electronic component is provided with the dust core. A soft magnetic powder including soft magnetic metal particles, the surfaces of which are covered by an inorganic insulating coating, the inorganic insulating coating having a first coating part in contact with the surfaces of the soft magnetic metal particles, and a second coating part formed on the outside of the first coating part, the first coating part including phosphorus and oxygen, and the second coating part including silicon and oxygen.
1. A soft magnetic powder comprising a soft magnetic metal particle whose surface is coated with an inorganic insulating film, wherein
the inorganic insulating film comprises a first coating part in contact with the surface of the soft magnetic metal particle, and a second coating part formed at an outer side of the first coating part, and wherein,
the first coating part includes phosphorus and oxygen,
the second coating part includes silicon and oxygen,
an intermediate layer including phosphorus and silicon is formed between the first coating part and the second coating part in the inorganic insulating film,
a total thickness (S1) of the inorganic insulating film is 200 nm or less; and
a ratio of a thickness (M1) of the intermediate layer to the total thickness (S1) of the inorganic insulating film satisfies 0.05<M1/S1≤0.2.
2. The soft magnetic powder according to claim 1 , wherein
a sum of a thickness (T 1 ) of the first coating part and a thickness (T 2 ) of the second coating part satisfies 10 nm≤T 1 +T 2≤150 nm; and
a ratio of the thickness (T 2 ) of the second coating part to the sum (T 1 +T 2 ) of the thickness of the first coating part and the thickness of the second coating part satisfies 20%≤T 2 /(T 1 +T 2 )≤90%.
3. The soft magnetic powder according to claim 2 , wherein
the ratio of the thickness (T 2 ) of the second coating part to the sum (T 1 +T 2 ) of the thickness of the first coating part and the thickness of the second coating part satisfies 50%≤T 2 /(T 1 +T 2 )≤80%.
4. A magnetic core including the soft magnetic powder according to claim 1 .
5. An electronic component comprising the magnetic core according to claim 1 .
6. A soft magnetic powder comprising a soft magnetic metal particle whose surface is coated with an inorganic insulating film, wherein
the inorganic insulating film comprises a first coating part in contact with the surface of the soft magnetic metal particle, and a second coating part formed at an outer side of the first coating part, and wherein,
the first coating part includes phosphorus and oxygen,
the second coating part includes silicon and oxygen,
an intermediate layer including phosphorus and silicon is formed between the first coating part and the second coating part in the inorganic insulating film,
the first coating part includes at least one element (a) selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba; and
a content ratio (α/P) by mole of the at least one element α to phosphorus (P) in the first coating part satisfies 0.05≤α/P≤0.5.
7. The soft magnetic powder according to claim 6 , wherein
the at least one element α included in the first coating part is Na.
8. The soft magnetic powder according to claim 6 , wherein
a sum of a thickness (T 1 ) of the first coating part and a thickness (T 2 ) of the second coating part satisfies 10 nm≤T 1 +T 2≤150 nm; and
a ratio of the thickness (T 2 ) of the second coating part to the sum (T 1 +T 2 ) of the thickness of the first coating part and the thickness of the second coating part satisfies 20%≤T 2 /(T 1 +T 2 )≤90%.
9. The soft magnetic powder according to claim 8 , wherein
the ratio of the thickness (T 2 ) of the second coating part to the sum (T 1 +T 2 ) of the thickness of the first coating part and the thickness of the second coating part satisfies 50%≤T 2 /(T 1 +T 2 )≤80%.
10. A magnetic core including the soft magnetic powder according to claim 6 .
11. An electronic component comprising the magnetic core according to claim 10 .
12. A soft magnetic powder comprising a soft magnetic metal particle whose surface is coated with an inorganic insulating film, wherein
the inorganic insulating film comprises a first coating part in contact with the surface of the soft magnetic metal particle, and a second coating part formed at an outer side of the first coating part, and wherein,
the first coating part includes phosphorus and oxygen, and the second coating part includes silicon and oxygen,
the first coating part includes at least one element (β) selected from the group consisting of Zn and Al; and
a content ratio (B/P) by mole of the at least one element β to phosphorus (P) in the first coating part satisfies 0.5≤B/P≤0.8.
13. The soft magnetic powder according to claim 12 , wherein
the at least one element β included in the first coating part is Zn.
14. The soft magnetic powder according to claim 12 , wherein
a sum of a thickness (T 1 ) of the first coating part and a thickness (T 2 ) of the second coating part satisfies 10 nm≤T 1 +T 2≤150 nm; and
a ratio of the thickness (T 2 ) of the second coating part to the sum (T 1 +T 2 ) of the thickness of the first coating part and the thickness of the second coating part satisfies 20%≤T 2 /(T 1 +T 2 )≤90%.
15. The soft magnetic powder according to claim 14 , wherein
the ratio of the thickness (T 2 ) of the second coating part to the sum (T 1 +T 2 ) of the thickness of the first coating part and the thickness of the second coating part satisfies 50%≤T 2 /(T 1 +T 2 )≤80%.
16. The soft magnetic powder according to claim 14 , wherein
an intermediate layer including phosphorus and silicon is formed between the first coating part and the second coating part in the inorganic insulating film.
17. A magnetic core including the soft magnetic powder according to claim 12 .
18. An electronic component comprising the magnetic core according to claim 17 .