# US 12,191,065 B2 · Metal magnetic particle, inductor, method for manufacturing metal magnetic particle, and method for manufacturing metal magnetic core > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,065 B2 - Document ID: US12191065B2 - Status: Granted - Kind: B2 - Application number: 17/201,801 - Filed: 2021-03-15 - Published: 2021-09-30 - Granted: 2025-01-07 - Earliest claimed: 2020-03-27 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Takuya Ishida; Makoto Yamamoto; Katsutoshi Uji; Yuya Ishida; Mitsuru Odahara - Web page: https://patentgrep.com/patent/US12191065B2 ## CPC - H01F 27/255: made from particles (H01F27/26 takes precedence) - H01F 1/147: Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)} - H01F 1/24: the particles being insulated - H01F 1/33: mixtures of metallic and non-metallic particles; metallic particles having oxide skin - H01F 3/08: made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06) - H01F 41/0246: {Manufacturing of magnetic circuits by moulding or by pressing powder (magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36)} - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract A metal magnetic particle provided with an oxide layer on a surface of an alloy particle containing Fe and Si, wherein the oxide layer has a first oxide layer, a second oxide layer, and a third oxide layer from the alloy particle side. Also, in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the first oxide layer is a layer where Si content takes a local maximum value, the second oxide layer is a layer where Fe content takes a local maximum value, and the third oxide layer is a layer where Si content takes a local maximum value. ## Claims ### Claim 1 A metal magnetic core, comprising: metal magnetic particles, the metal magnetic particles comprising: an oxide layer formed on a surface of an alloy particle containing Fe and Si, the oxide layer including a first oxide layer, a second oxide layer, and a third oxide layer, the first oxide layer is formed directly on the alloy particle, the second oxide layer formed over the first oxide layer, and the third oxide layer formed over the second oxide layer, and wherein in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the first oxide layer is a layer in which Si content takes a local maximum value, and the first oxide layer contains Fe and Si, the second oxide layer is a layer in which Fe content takes a local maximum value, the amount of Fe in the second oxide layer is greater than the amount of Si in the second oxide layer, the third oxide layer is a layer in which Si content takes a local maximum value, and the metal magnetic particles are joined to each other with the oxide layer to form the metal magnetic core. ### Claim 2 (depends on 1) A metal magnetic core according to claim 1, wherein a weight percentage of Si in the alloy particle is from 1.5 parts by weight to 8.0 parts by weight with respect to 100 parts by weight of a total weight of the Fe and the Si. ### Claim 3 (depends on 1) A metal magnetic core according to claim 1, wherein the alloy particle contains smaller than 1.0 part by weight of Cr with respect to 100 parts by weight of a total weight of the Fe and the Si. ### Claim 4 (depends on 1) A metal magnetic core according to claim 1, wherein the oxide layer further includes a fourth oxide layer provided on a surface of the third oxide layer, and in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the fourth oxide layer is a layer in which Fe content takes a local maximum value. ### Claim 5 (depends on 1) An inductor comprising: the metal magnetic core according to claim 1. ### Claim 6 (depends on 2) A metal magnetic core according to claim 2, wherein the alloy particle contains smaller than 1.0 part by weight of Cr with respect to 100 parts by weight of a total weight of the Fe and the Si. ### Claim 7 (depends on 2) A metal magnetic core according to claim 2, wherein the oxide layer further includes a fourth oxide layer provided on a surface of the third oxide layer, and in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the fourth oxide layer is a layer in which Fe content takes a local maximum value. ### Claim 8 (depends on 3) A metal magnetic core according to claim 3, wherein the oxide layer further includes a fourth oxide layer provided on a surface of the third oxide layer, and in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the fourth oxide layer is a layer in which Fe content takes a local maximum value. ### Claim 9 (depends on 6) A metal magnetic core according to claim 6, wherein the oxide layer further includes a fourth oxide layer provided on a surface of the third oxide layer, and in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the fourth oxide layer is a layer in which Fe content takes a local maximum value. ### Claim 10 (depends on 2) An inductor comprising: the metal magnetic core according to claim 2. ### Claim 11 (depends on 3) An inductor comprising: the metal magnetic core according to claim 3. ### Claim 12 (depends on 4) An inductor comprising: the metal magnetic core according to claim 4. ### Claim 13 (depends on 1) A metal magnetic core according to claim 1, wherein a ratio of the Fe content to the Si content (Fe content/Si content) at the point where Fe content of the second oxide layer takes the local maximum value is equal to or larger than about 22 and equal to or smaller than about 27. ### Claim 14 (depends on 1) A metal magnetic core according to claim 1, wherein a maximum value of Fe content in the first oxide layer is greater than a maximum value of Fe content in the third oxide layer. ### Claim 15 (depends on 1) A metal magnetic core according to claim 1, wherein a minimum value of Fe content in the first oxide layer is greater than a minimum value of Fe content in the third oxide layer.