# US 7,744,703 B2 · Fe-based amorphous alloy strip

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- Number: US 7,744,703 B2
- Document ID: US7744703B2
- Status: Granted
- Kind: B2
- Application number: 11/887,705
- Filed: 2006-04-05
- Published: 2009-10-01
- Granted: 2010-06-29
- Earliest claimed: 2005-04-08
- Assignees: Nippon Steel Corporation
- Inventors: Takeshi Imai; Shigekatsu Ozaki; Yuuji Hiramoto; Yuichi Sato; Hiroaki Sakamoto
- Web page: https://patentgrep.com/patent/US7744703B2

## CPC

- H01F 1/15308: {based on Fe/Ni (H01F1/15325 takes precedence)}
- C22C 45/02: with iron as the major constituent
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

The present invention provides a Fe—B—Si system amorphous alloy thin strip excellent in high magnetic flux density, thermal stability, amorphous formability improved workability and low core loss. The present invention further provides a Fe—B—Si system amorphous alloy thin strip which has the reduced cost without using high purity iron resources such as an electrolytic iron as iron resources used in an amorphous alloy thin strip, and also has core loss less than 0.10 W/kg at W13/50 in soft magnetic property in alternating-current field. The Fe—B—Si system amorphous alloy thin strip according to the present invention contains an appropriate amounts of N, C, P to improve thermal stability, amorphous formability, workability (brittleness), and core loss without deteriolating magnetic flux density, and contains, in atomic %, B: 5-25%, Si: 1-30%, N: 0.001-0.2%, C: 0.003-10%, P: 0.001-0.2% and the balance being Fe and unavoidable impurities, and optionally contains Co or Ni substituted to less than 15% of the Fe amount, or Cr at less than 5% substituted to the Fe amount. Further, Mn: 0.15-0.5 mass %, S: 0.004-0.05 mass % can be included.

## Claims

### Claim 1

An Fe-based amorphous alloy strip characterized by containing, by atm %, B: 5 to 12%, Si: 1 to 5%, N: 0.001 to 0.2%, C: 1 to 10%, and P: 0.001 to 0.2%, and a balance of Fe and unavoidable impurities.

### Claim 2

An Fe-based amorphous alloy strip superior in soft magnetic properties under an alternating current characterized by containing, by atm %, B: 12 to 16%, Si: 2 to 7%, N: 0.001 to 0.2%, Fe: 80 to 82%, and at least one of Co, Ni, and Cr: 0.01 to 1%, and further containing, by mass %, P: 0.008 to 0.1%, Mn: 0.15 to 0.5%, and S: 0.004 to 0.05%, and a balance of Fe and unavoidable impurities.

### Claim 3 (depends on 2)

An Fe-based amorphous alloy strip superior in soft magnetic properties under an alternating current as set forth in claim 2 characterized by further containing, by atm %, C: 0.003 to 2%.