Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making
Abstract
A method of making a permanent magnet is disclosed wherein (1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and (2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magneticmore »
- Inventors:
- Issue Date:
- Research Org.:
- Iowa State Univ., Ames, IA (United States)
- OSTI Identifier:
- 187083
- Patent Number(s):
- 5,486,240
- Application Number:
- PAN: 8-232,837
- Assignee:
- Iowa State Univ. Research Foundation, Inc., Ames, IA (United States)
- DOE Contract Number:
- W-7405-ENG-82
- Resource Type:
- Patent
- Resource Relation:
- Other Information: PBD: 23 Jan 1996
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; 36 MATERIALS SCIENCE; PERMANENT MAGNETS; FABRICATION; RARE EARTH ALLOYS; GRAIN REFINEMENT; IRON ALLOYS; COBALT ALLOYS; BORON ALLOYS; TRANSITION ELEMENT ALLOYS; CARBIDES; NITRIDES; AMORPHOUS STATE; CARBON ADDITIONS; NITROGEN ADDITIONS
Citation Formats
McCallum, R W, and Branagan, D J. Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making. United States: N. p., 1996.
Web.
McCallum, R W, & Branagan, D J. Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making. United States.
McCallum, R W, and Branagan, D J. Tue .
"Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making". United States.
@article{osti_187083,
title = {Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making},
author = {McCallum, R W and Branagan, D J},
abstractNote = {A method of making a permanent magnet is disclosed wherein (1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and (2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magnetic properties. 33 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1996},
month = {1}
}