Soft magnetic iron sheet, method for producing soft magnetic iron sheet, and, iron core and dynamo-electric machine, each using soft magnetic iron sheet

Patent metadata

Field	Value
Publication number	US-12512239-B2
Application number	US-202118019518-A
Country	US
Kind code	B2
Filing date	May 11, 2021
Priority date	Sep 29, 2020
Publication date	Dec 30, 2025
Grant date	Dec 30, 2025

Abstract

The present invention provides a soft magnetic iron sheet exhibiting a high saturation magnetic flux density and a low iron loss as compared with an electromagnetic pure iron sheet, a method for producing the soft magnetic iron sheet, and, an iron core and a dynamo-electric machine, each using the soft magnetic iron sheet. The soft magnetic iron sheet according to the present invention includes: iron as a main component; and nitrogen, in which the soft magnetic iron sheet includes, along a thickness direction of the soft magnetic iron sheet: a high nitrogen concentration layer having a nitrogen concentration of 2 at. % to 11 at. %; a low nitrogen concentration layer having a nitrogen concentration of half or less of the nitrogen concentration of the high nitrogen concentration layer; and a nitrogen concentration transition layer connecting the nitrogen concentration of the high nitrogen concentration layer and the nitrogen concentration of the low nitrogen concentration layer, and wherein a surface layer region including at least both main surfaces of the soft magnetic iron sheet is the low nitrogen concentration layer.

First claim

The invention claimed is:

1 . A soft magnetic iron sheet comprising: iron as a main component; nitrogen; and cobalt,
wherein the soft magnetic iron sheet includes, in a thickness direction of the soft magnetic iron sheet: a high nitrogen concentration layer having a nitrogen concentration of 2 at. % or more and 11 at. % or less; a low nitrogen concentration layer having a nitrogen concentration of half or less of the nitrogen concentration of the high nitrogen concentration layer; and a nitrogen concentration transition layer connecting the nitrogen concentration of the high nitrogen concentration layer and the nitrogen concentration of the low nitrogen concentration layer, wherein a surface layer region including at least both main surfaces of the soft magnetic iron sheet is the low nitrogen concentration layer, and the high nitrogen concentration layer is in an inner region, and wherein the soft magnetic iron sheet has a cobalt concentration distribution in which a concentration of the cobalt in the surface layer region is higher than a concentration of the cobalt in the inner region, along the thickness direction of the soft magnetic iron sheet.

2 . The soft magnetic iron sheet according to claim 1 , wherein the nitrogen concentration transition layer has an average nitrogen concentration gradient of 0.1 at. %/μm or more and 10 at. %/μm or less.

3 . The soft magnetic iron sheet according to claim 1 , wherein the low nitrogen concentration layer has a nitrogen concentration of 1 at. % or less.

4 . The soft magnetic iron sheet according to claim 1 , having a saturation magnetic flux density of more than 2.14 T, and an iron loss, under conditions of a magnetic flux density of 1.0 T and a frequency of 400 Hz, of less than 40 W/kg.

5 . The soft magnetic iron sheet according to claim 1 , wherein the soft magnetic iron sheet has a thickness of 0.01 mm or more and 1 mm or less.

6 . The soft magnetic iron sheet according to claim 1 , comprising: an α phase; an α′ phase; and an α″ phase,
wherein the α phase is a main phase and the α″ phase has a volume ratio of 10% or more.

7 . The soft magnetic iron sheet according to claim 6 , wherein the α″ phase is a crystal phase in which a ratio of a c-axis length to an a-axis length of lattice constant is different from a ratio of a c-axis length to an a-axis length of lattice constant of Fe 16 N 2 having a stoichiometric composition.

8 . The soft magnetic iron sheet according to claim 1 , wherein a total of elements other than the iron and the nitrogen is less than 1 at. %.

9 . The soft magnetic iron sheet according to claim 1 , wherein the concentration of cobalt in the surface layer region is about 30 at. % to 60 at. % and the concentration of cobalt in the inner region is about 20 at. % to 25 at %.

10 . The soft magnetic iron sheet according to claim 9 , wherein the concentration of cobalt in the surface layer region is about 30 at. % to 55 at. % and the concentration of cobalt in the inner region is about 20 at. %.

11 . An iron core comprising a laminated body of soft magnetic iron sheets, wherein the soft magnetic iron sheets are the soft magnetic iron sheets according to claim 1 .

12 . A dynamo-electric machine comprising an iron core, wherein the iron core is the iron core according to claim 11 .

Assignees

• Hitachi Ltd

Inventors

• Komuro Matahiro
• ASARI Yusuke
• Shinagawa Kazuya
• Tamura Shinya
• Tabata Tomohiro
• Terada Shohei

Classifications

• H02K1/02

  characterised by the magnetic material · CPC title

• C22C2202/02

  Magnetic · CPC title

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title

• C22C38/10

  containing cobalt · CPC title

• C22C38/001

  containing N · CPC title