MAGNETIC ALLOY MATERIAL AND METHOD OF MAKING THE MAGNETIC ALLOY MATERIAL

• US 20060231163A1
• Filed: 03/30/2006
• Published: 10/19/2006
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Hitachi Metals Limited (Hitachi Metals (Thailand) Ltd.)
• Original Assignee: Hitachi Metals Limited (Hitachi Metals (Thailand) Ltd.)
• Inventors: Tomizawa, Hiroyuki, HIROSAWA, Satoshi, Kogure, Ryosuke
• Granted Patent: US 7,578,892 B2
• Time in Patent Office: Days
• US Class Current: 148/105
• CPC Class Codes: H01F 1/015 Metals or alloys

Abstract

A magnetic alloy material according to the present invention has a composition represented by Fe_100-a-b-cRE_aA_bCo_c, where RE is a rare-earth element always including La, A is either Si or Al, 6 at %≦a≦11 at %, 8 at %≦b≦18 at %, and 0 at %≦c≦9 at %, and has either a two phase structure consisting essentially of an α-Fe phase and an (RE, Fe, A) phase including 30 at % to 90 at % of RE or a three phase structure consisting essentially of the α-Fe phase, the (RE, Fe, A) phase including 30 at % to 90 at % of RE and an RE(Fe, A)₁₃ compound phase with an NaZn₁₃-type crystal structure. The respective phases have an average minor-axis size of 40 nm to 2 μm.

Claims

1. A magnetic alloy material having a composition represented by the general formula:

Fe_100-a-b-cRE_aA_bCo_c, where RE is a rare-earth element that always includes La, A is either Si or Al, 6 at %≦

a≦

11 at %, 8 at %≦

b≦

=18 at %, and 0 at %≦

c≦

9 at %, and having either a two phase structure consisting essentially of an α

-Fe phase and an (RE, Fe, A) phase including 30 at % to 90 at % of RE or a three phase structure consisting essentially of the α

-Fe phase, the (RE, Fe, A) phase including 30 at % to 90 at % of RE and an RE(Fe, A)₁₃ compound phase with an NaZn₁₃-type crystal structure, the respective phases having an average minor-axis size of 40 nm to 2 μ

m.

2. The magnetic alloy material of claim 1, wherein the mole fraction a in the general formula is from 7 at % to 9 at %.

3. The magnetic alloy material of claim 1, wherein the (RE, Fe, A) phase is an REFeSi compound phase.

4. The A magnetic alloy material of claim 1 having a composition represented by the general formula:

Fe_100-a-b-cRE_aA_bCo_c, where RE is a rare-earth element that always includes La, A is either Si or Al, 6 at %≦

a≦

11 at %, 8 at %≦

b≦

18 at %, and 0 at %≦

c≦

9 at %, and having either a two phase structure consisting essentially of an α

-Fe phase and an (RE, Fe, A) phase including 30 at % to 90 at % of RE or a three phase structure consisting essentially of the α

-Fe phase, the (RE, Fe, A) phase including 30 at % to 90 at % of RE and an RE(Fe, A)₁₃ compound phase with an NaZn₁₃-type crystal structure, the respective phases having an average minor-axis size of 40 nm to 2 μ

m, wherein Co substitutes for Fe in at least one of the α

-Fe phase, the (RE, Fe, A) phase and the RE(Fe, A)₁₃ compound phase.

5. The magnetic alloy material of claim 1, wherein the magnetic alloy material has an oxygen concentration of 0.07 at % to 0.18 at %.

6. The magnetic alloy material of claim 1, wherein the magnetic alloy material is changeable into the RE(Fe, A)₁₃ compound phase almost entirely by being thermally treated at temperature of 600°

C. or more for at least 10 seconds.

7. The magnetic alloy material of claim 1, wherein the magnetic alloy material is in the form of powder, of which the particles have minor-axis sizes of 2 μ

m to 200 μ

m.

8. The magnetic alloy material of claim 7, wherein particles of the powder have a minor-axis size of less than 10 μ

m.

9. A method of making a magnetic alloy material, the method comprising the steps of:

preparing a melt of an alloy material having a predetermined composition; and

rapidly quenching and solidifying the melt of the alloy material such that an average quenching rate is 2×

10⁴°

C./s to 2×

10⁶°

C./s within the temperature range of 1,500°

C. to 600°

C., thereby obtaining a rapidly solidified alloy having a composition represented by the formula;

Fe_100-a-b-cRE_aA_bCo_c, where RE is a rare-earth element that always includes La, A is either Si or Al, 6 at %≦

a≦

11 at %, 8 at %≦

b≦

18 at %, and 0 at %≦

c≦

9 at %, and having either a two phase structure consisting essentially of an α

-Fe phase and an (RE, Fe, A) phase including 30 at % to 90 at % of RE or a three phase structure consisting essentially of the α

-Fe phase, the (RE, Fe, A) phase including 30 at % to 90 at % of RE and an RE(Fe, A)₁₃ compound phase with an NaZn₁₃-type crystal structure, the respective phases having an average minor-axis size of 40 nm to 2 μ

m.

10. The method of claim 9, wherein the mole fraction a in the general formula is from 7 at % to 9 at %.

11. The method of claim 9, wherein the (RE, Fe, A) phase is an REFeSi compound phase.

13. The method of claim 9, wherein the rapidly solidified alloy has a thickness of 2 μ

m to 200 μ

m.

14. The method of claim 9, wherein the step of obtaining the rapidly solidified alloy includes setting the teeming temperature of the alloy material higher than the liquidus temperature of the alloy material by 50°

C. to 150°

C.

15. The method of claim 9, wherein the step of obtaining the rapidly solidified alloy includes controlling the roller peripheral velocity of a chill roller within the range of 3 m/s to 30 m/s.

16. The method of claim 9, further comprising the step of pulverizing the rapidly solidified alloy, thereby making a powder, of which the particles have minor-axis sizes of 2 μ

m to 200 μ

m.

17. The method of claim 16, wherein particles of the powder have a minor-axis size of less than 10 μ

m.

18. A method of making a sintered body of a magnetic alloy, the method comprising the steps of:

making the powder by the method of claim 16;

compacting the powder to make a compact; and

sintering the compact.

19. The method of claim 18, wherein the step of sintering includes sintering the compact within the temperature range of 600°

C. to less than 1,320°

C.

20. The method of claim 19, wherein the step of sintering includes sintering the compact within the temperature range for ten seconds to eight hours.

12. A method of making a magnetic alloy material, the method comprising the steps of:

preparing a melt of an alloy material having a predetermined composition; and

rapidly quenching and solidifying the melt of the alloy material such that an average quenching rate is 2×

10⁴°

C./s to 2×

10⁶°

C./s within the temperature range of 1500°

C. to 600°

C., thereby obtaining a rapidly solidified alloy having a composition represented by the formula;

Fe_100a-b-cRE_aA_bCo_c, where RE is a rare-earth element that always includes La, A is either Si or Al, 6 at %≦

a≦

11 at %, 8 at %≦

b≦

18 at %, and 0 at %≦

c≦

9 at %, and having either a two phase structure consisting essentially of an α

-Fe phase and an (RE, Fe, A) phase including 30 at % to 90 at % of RE or a three phase structure consisting essentially of the α

-Fe phase, the (RE, Fe, A) phase including 30 at % to 90 at % of RE and an RE(Fe, A)₁₃ compound phase with an NaZn₁₃-type crystal structure, the respective phases having an average minor-axis size of 40 nm to 2 μ

m., wherein Co substitutes for Fe in at least one of the α

-Fe phase, the (RE, Fe, A) phase and the RE(Fe, A)₁₃ compound phase.