US 11,718,901 B2
Method for producing coated magnetic powder, method for producing dust core, and method for producing electromagnetic component
Asako Watanabe, Itami (JP); and Tomoyuki Ueno, Itami (JP)
Assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP); and SUMITOMO ELECTRIC SINTERED ALLOY, LTD., Takahashi (JP)
Appl. No. 16/306,003
Filed by Sumitomo Electric Industries, Ltd., Osaka (JP); and Sumitomo Electric Sintered Alloy, Ltd., Takahashi (JP)
PCT Filed May 17, 2017, PCT No. PCT/JP2017/018541
§ 371(c)(1), (2) Date Nov. 30, 2018,
PCT Pub. No. WO2017/208824, PCT Pub. Date Dec. 7, 2017.
Claims priority of application No. 2016-107750 (JP), filed on May 30, 2016.
Prior Publication US 2019/0160527 A1, May 30, 2019
Int. Cl. C22C 38/02 (2006.01); H01F 1/26 (2006.01); H01F 41/02 (2006.01); B22F 1/102 (2022.01); B22F 1/16 (2022.01); C22C 38/06 (2006.01); H01F 1/147 (2006.01); B22F 3/02 (2006.01); B22F 3/24 (2006.01); H01F 41/04 (2006.01)
CPC C22C 38/02 (2013.01) [B22F 1/102 (2022.01); B22F 1/16 (2022.01); B22F 3/02 (2013.01); B22F 3/24 (2013.01); C22C 38/06 (2013.01); H01F 1/14766 (2013.01); H01F 1/14791 (2013.01); H01F 1/26 (2013.01); H01F 41/02 (2013.01); H01F 41/0246 (2013.01); H01F 41/04 (2013.01); B22F 2003/248 (2013.01); B22F 2301/35 (2013.01); B22F 2998/10 (2013.01); C22C 2202/02 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method for producing a coated magnetic powder in which particle surfaces of a soft magnetic powder are coated with a silicone resin, the method comprising:
preparing a silicone emulsion by adding a silicone resin into water containing a surfactant with stirring, the silicone emulsion consisting of the silicone resin, the surfactant and the water;
applying the silicone emulsion onto particle surfaces of a soft magnetic powder; and
drying the soft magnetic powder after the silicone emulsion is applied,
wherein the surfactant is a nonionic surfactant having a polyoxyethylene structure and has a weight-average molecular weight in an inclusive range of 300 or more through 700 or less, and an average particle size of particles of the silicone resin dispersed in the silicone emulsion is 200 nm or more,
the silicone resin is dimethyl silicone resin or methyl phenyl silicone resin.