Magnetic core based on a nanocrystalline magnetic alloy

Patent metadata

Field	Value
Publication number	US-2016196908-A1
Application number	US-201514591491-A
Country	US
Kind code	A1
Filing date	Jan 7, 2015
Priority date	Jan 7, 2015
Publication date	Jul 7, 2016
Grant date	—

Abstract

A magnetic core includes a nanocrystalline alloy ribbon having a composition represented by FeCu x B y Si z A a X b , where 0.6≦x<1.2, 10≦y≦20, 0≦(y+z)≦24, and 0≦a≦10, 0≦b≦5, all numbers being in atomic percent, with the balance being Fe and incidental impurities, and where A is an optional inclusion of at least one element selected from Ni, Mn, Co, V, Cr, Ti, Zr, Nb, Mo, Hf, Ta and W, and X is an optional inclusion of at least one element selected from Re, Y, Zn, As, In, Sn, and rare earth elements. The nanocrylstalline alloy ribbon has a local structure such that nanocrystals with average particle sizes of less than 40 nm are dispersed in an amorphous matrix and are occupying more than 30 volume percent of the ribbon.

First claim

What is claimed is:

1 . A magnetic core comprising:
a nanocrystalline alloy ribbon having a composition represented by FeCu x B y Si z A a X b , where 0.6≦x<1.2, 10≦y≦20, 0≦(y+z)≦24, and 0≦a≦10, 0≦b≦5, all numbers being in atomic percent, with the balance being Fe and incidental impurities, and where A is an optional inclusion of at least one element selected from Ni, Mn, Co, V, Cr, Ti, Zr, Nb, Mo, Hf, Ta and W, and X is an optional inclusion of at least one element selected from Re, Y, Zn, As, In, Sn, and rare earth elements, the nanocrylstalline alloy ribbon having a local structure such that nanocrystals with average particle sizes of less than 40 nm are dispersed in an amorphous matrix and are occupying more than 30 volume percent of the ribbon.

2 . The magnetic core of claim 1 , wherein
the ribbon has been subjected to heat treatment at a temperature in a range of from 430° C. to 550° C. at a heating rate of 10° C./s or more for less than 30 seconds, with a tension between 1 MPa and 500 MPa applied during the heat treatment; and the ribbon has been wound, after the heat treatment, to form a wound core.

3 . The magnetic core of claim 2 , wherein
the core has been further heat-treated in wound form at a temperature from 400° C. to 500° C. for 1.8 ks-10.8 ks in a magnetic field of less than 4 kA/m applied along the core's circumference direction.

4 . The magnetic core of claim 1 , wherein
the core is a wound core, and a round portion of the core is comprised of a ribbon whose radius of curvature is between 10 mm and 200 mm when let loose, and the round portion of the core is such that a ribbon relaxation rate defined by (2−R w /R f ) is larger than 0.93, where R w and R f are, respectively, ribbon radius of curvature prior to ribbon release and ribbon radius of curvature after ribbon release and when the core is free of constraint.

5 . The magnetic core of claim 2 , wherein the nanocrystalline alloy ribbon has been heat-treated by an average heating rate of more than 10° C./s from room temperature to a predetermined holding temperature which exceeds 430° C. and less than 550° C., with the holding time of less than 30 seconds.

6 . The magnetic core of claim 2 , wherein the nanocrystalline alloy ribbon of has been heat-treated by an average heating rate of more than 10° C./s from 300° C. to a predetermined holding temperature which exceeds 450° C. and is less than 520° C., with the holding time of less than 30 seconds.

7 . The magnetic core of claim 6 , wherein the holding time is less than 20 seconds.

8 . The magnetic core of claim 1 , wherein the composition of the nanocrystalline alloy ribbon contains at least 78 at. % Fe.

9 . The magnetic core of claim 1 , wherein the composition of the nanocrystalline alloy ribbon contains from 0.01 atomic percent to 10 atomic percent of at least one selected from Ni, Mn, Co, V, Cr, Ti, Zr, Nb, Mo, Hf, Ta and W.

10 . The magnetic core of claim 9 , wherein the composition of the nanocrystalline alloy contains at least one selected from Nb, Zr, Ta and Hf in an amount that is below 0.4 atomic percent in total.

11 . The magnetic core of claim 1 , wherein in the composition of the nanocrystalline alloy ribbon, a total amount of Re, Y, Zn, As, In, Sn, and rare earth elements is less than 2.0 atomic percent.

12 . The magnetic core of claim 11 , wherein the total amount of Re, Y, Zn, As, In, Sn, and rare earth elements is less than 1.0 atomic percent.

13 . An electrical power distribution transformer comprising the magnetic core of claim 1 .

14 . A magnetic inductor for electrical power management operated at commercial and high frequencies, comprising the magnetic core of claim 1 .

15 . A transformer utilized in power electronics, comprising the magnetic core of claim 1 .

16 . The magnetic core of claim 1 , having a coercivity of less than 4 A/m.

17 . A device comprising the magnetic core of claim 1 ,
the core having a core loss of 0.2 W/kg-0.5 W/kg at 60 Hz and 1.6 T and a core loss of 0.15 W/kg-0.4 W/kg at 50 Hz and 1.6 T, and having a B 800 exceeding 1.7 T, and the device being an electrical power distribution transformer, or a magnetic inductor for electrical power management operated at commercial and high frequencies.

18 . A device comprising the magnetic core of claim 1 ,
the core having a core loss of less than 30 W/kg at 10 kHz and an operating induction level of 0.5 T, and having a B 800 exceeding 1.7 T, and the device being a magnetic inductor for electrical power management operated at commercial and high frequencies, or a transformer utilized in power electronics.

19 . The magnetic core of claim 1 , having B r /B 800 exceeding 0.8, and B 800 exceeding 1.7 T.

20 . A method of manufacturing the magnetic core of claim 1 , comprising:
heat treating the ribbon at a temperature in a range of from 430° C. to 550° C. at a heating rate of 10° C./s or more for less than 30 seconds, with a tension between 1 MPa and 500 MPa applied during the heat treating; and after the heat treating, winding the ribbon to form a wound core.

21 . The method of claim 20 , further comprising:
after the winding the ribbon, further heat treating the core in wound form at a temperature from 400° C. to 500° C. for 1.8 ks-10.8 ks in a magnetic field of less than 4 kA/m applied along core's circumference direction.

22 . The method of claim 20 , wherein the heat treating before the winding is performed by an average heating rate of more than 10° C./s from room temperature to a predetermined holding temperature which exceeds 430° C. and less than 550° C., with the holding time of less than 30 seconds.

23 . A method of manufacturing a magnetic core, comprising:
heat treating an amorphous alloy ribbon at a temperature in a range of from 430° C. to 550° C. at a heating rate of 10° C./s or more for less than 30 seconds, with a tension between 1 MPa and 500 MPa applied during the heat treating, the ribbon having a composition represented by FeCu x B y Si z A a X b , where 0.6≦x<1.2, 10≦y≦20, 0≦(y+z)≦24, and 0≦a≦10, 0≦b≦5, all numbers being in atomic percent, with the balance being Fe and incidental impurities, and where A is an optional inclusion of at least one element selected from Ni, Mn, Co, V, Cr, Ti, Zr, Nb, Mo, Hf, Ta and W, and X is an optional inclusion of at least one element selected from Re, Y, Zn, As, In, Sn, and rare earth elements; and after the heat treating, winding the ribbon to form a wound core.

Assignees

• Metglas Inc
• Hitachi Metals Ltd

Inventors

• Ohta Motoki
• Ito Naoki

Classifications

• C22C38/02

  containing silicon · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• C22C38/16

  containing copper · CPC title

• C21D8/125

  with application of tension · CPC title

• C22C38/12

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