Method for making nano-scale grain metal powders having excellent high-frequency characteristic and method for making high-frequency soft magnetic core using the same

• US 7,175,717 B2
• Filed: 10/14/2003
• Issued: 02/13/2007
• Est. Priority Date: 08/14/2003
• Status: Active Grant

• Current Assignee: Amosense Co., Ltd.
• Original Assignee: Amosense Co., Ltd.
• Inventors: Song, Yong Sul, Kim, Hie Jin
• Primary Examiner(s): Sheehan; John P.
• Application Number:
  US10/683,396
• Publication Number:
  US 20050034787A1
• Time in Patent Office: 1,218 Days
• Field of Search: None
• US Class Current: 148/104
• CPC Class Codes: B22F 1/052 characterised by a mixture of particles of different sizes or by the particle size distribution
• CPC Class Codes: B22F 1/08 Metallic powder characterised by particles having an amorphous microstructure
• CPC Class Codes: B22F 2201/02 Nitrogen
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 9/007 Transformation of amorphous into microcrystalline state
• CPC Class Codes: B22F 9/008 Rapid solidification processing
• CPC Class Codes: B22F 9/04 starting from solid material, e.g. by crushing, grinding or milling C22C1/1084 takes precedence; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C
• CPC Class Codes: H01F 1/15333 containing nanocrystallites, e.g. obtained by annealing
• CPC Class Codes: H01F 41/0226 from amorphous ribbons

Abstract

A method for making a nano-scale amorphous soft magnetic powders obtained by thermally processing and crystallizing amorphous ribbons produced using a rapid solidification process (RSP) and crushing the same. The amorphous soft magnetic core having an excellent high-frequency characteristic is obtained by performing a preliminary thermal treatment of Fe-based amorphous metal ribbons produced by using RSP to then be converted into nano-scale grain metal ribbons, crushing the metal ribbons to thereby obtain nano-scale grain metal powders, classifying the nano-scale grain metal powders to then be mixed into a distribution of powder particles having an optimal uniform composition, mixing the mixed powder with a binder, and then forming a core, and annealing the formed core to then coat the core with an insulating resin.

Claims

1. A method of making a soft magnetic core having an excellent high-frequency characteristic comprising the steps of:

performing a thermal treatment of Fe-based amorphous metal ribbons produced by using a rapid solidification process (RSP) to then be converted into nano-scale grain metal ribbons;

crushing the nano-scale grain metal ribbons to thereby obtain nano-scale grain metal powders;

classifying the nano-scale grain metal powders to then be mixed into a distribution of powder particles made of first powders that have passed through a sieve of −

100˜

+140 meshes of 15˜

65%, and second powders that have passed through a sieve of −

140˜

+200 meshes of 35˜

85%;

mixing the mixed nano-scale grain metal powders with a binder, and then forming a core; and

annealing the formed core and then coating the core with an insulating resin.

2. The method of making a soft magnetic core of claim 1, wherein the nano-scale crystallization thermal treatment is performed at 400˜

600°

C., for 0.2˜

2 hours under a nitrogen atmosphere.

3. The method of making a soft magnetic core of claim 1, wherein the binder includes low melting point glass ranging from 1.5 to 5 wt %.

4. The method of making a soft magnetic core of claim 1, wherein the annealing process is performed for 0.2 to 3.8 hours at a temperature of 300 to 500°

C.

5. A method of making nano-scale grain metal powders for use in a soft magnetic core having an excellent high-frequency characteristic comprising the steps of:

performing a thermal treatment of Fe-based amorphous metal ribbons produced by using a rapid solidification process (RSP) to then be converted into nano-scale grain metal ribbons;

crushing the nano-scale grain metal ribbons to thereby obtain nano-scale grain metal powders; and

classifying the nano-scale grain metal powders to then be mixed into a distribution of powder particles made of first powders having passed through a sieve of −

100˜

+140 meshes of 15˜

65%, and second powders having passed through a sieve of −

140˜

+200 meshes of 35˜

85%.

6. The method of making nano-scale grain metal powders of claim 5, wherein the Fe-based amorphous metal ribbon which is used to obtain the nano-scale grain metal powder is made of an amorphous metal alloy comprising Fe as a basic composition, at least one element selected from the group consisting of P, C, B, Si, Al and Ge, and at least one selected from the group consisting of Nb, Cu, Hf, Zr, and Ti.

7. The method of making nano-scale grain metal powders of claim 6, wherein the nano-scale crystallization thermal treatment of the amorphous metal ribbon is performed at 400˜

600°

C., for 0.2˜

2 hours under a nitrogen atmosphere.