US 12,170,160 B2
Soft magnetic powder, dust core, magnetic element, and electronic device
Mayu Watanabe, Hachinohe (JP); and Mitsutaka Inui, Fujimi (JP)
Assigned to SEIKO EPSON CORPORATION, (JP)
Filed by SEIKO EPSON CORPORATION, Tokyo (JP)
Filed on Jan. 26, 2023, as Appl. No. 18/159,886.
Claims priority of application No. 2022-010906 (JP), filed on Jan. 27, 2022.
Prior Publication US 2023/0238162 A1, Jul. 27, 2023
Int. Cl. C22C 38/02 (2006.01); B22F 1/08 (2022.01); B22F 1/103 (2022.01); B22F 1/142 (2022.01); B22F 3/02 (2006.01); B22F 5/10 (2006.01); B22F 9/04 (2006.01); B22F 9/08 (2006.01); C22C 38/00 (2006.01); C22C 38/12 (2006.01); C22C 38/16 (2006.01); H01F 1/12 (2006.01); H01F 1/14 (2006.01); H01F 1/147 (2006.01); H01F 1/153 (2006.01); H01F 1/20 (2006.01); H01F 1/22 (2006.01); H01F 3/08 (2006.01); H01F 27/255 (2006.01)
CPC H01F 1/22 (2013.01) [H01F 1/12 (2013.01); H01F 1/14 (2013.01); H01F 1/147 (2013.01); H01F 1/14733 (2013.01); H01F 1/15308 (2013.01); H01F 1/15333 (2013.01); H01F 3/08 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A soft magnetic powder comprising:
a particle having a composition represented by FexCuaNbb (Si1-yBy)100-x-a-b,
a, b, and x being numbers whose units are atomic %, in which
0.3≤a≤2.0,
2.0≤b≤4.0, and
75.5≤x≤79.5, and
y being a number satisfying f(x)≤y≤0.99, and f(x)=(4×10−34)x17.56, wherein
the particle includes
a crystal grain having a grain size of 1.0 nm or more and 30.0 nm or less and containing a Fe—Si crystal,
a Cu segregation portion in which Cu is segregated, and
a crystal grain boundary,
a content proportion of the crystal grain in the particle is 30% or more, and
when the Cu segregation portion positioned in a surface layer portion of the particle and having a grain size of 2.0 nm or more and 10.0 nm or less is referred to as a first Cu segregation portion, and the Cu segregation portion positioned in an inner portion of the particle and having a grain size of 2.0 nm or more and 7.0 nm or less is referred to as a second Cu segregation portion,
a number proportion of the first Cu segregation portion in the Cu segregation portion positioned in the surface layer portion is 80% or more,
a number proportion of the second Cu segregation portion in the Cu segregation portion positioned in the inner portion is 80% or more, and
the number of the second Cu segregation portion is twice or more the number of the first Cu segregation portion.