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Title: Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making

A method of making a permanent magnet 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.
Inventors:
 [1];  [1]
  1. (Ames, IA)
Issue Date:
OSTI Identifier:
870261
Assignee:
Iowa State University Research Foundation, Inc. (Ames, IA) AMES
Patent Number(s):
US 5486240
Application Number:
08/232,837
Contract Number:
W-7405-ENG-82
Research Org:
Ames Laboratory (AMES), Ames, IA; Iowa State University, Ames, IA (US)
Country of Publication:
United States
Language:
English
Subject:
carbide; nitride; grain; refined; rare; earth-iron-boron; permanent; magnet; method; melt; formed; base; alloy; composition; comprising; earth; elements; transition; metal; selected; zr; hf; nb; provided; substantially; stoichiometric; amounts; form; thermodynamically; stable; compound; carbonitride; rapidly; solidified; manner; particulates; amorphous; metallic; glass; structure; dispersion; primary; trc; trn; precipitates; heated; crystallization; temperature; nucleate; grow; hard; magnetic; phase; optimum; size; secondary; dispersed; boundaries; crystallized; consolidated; elevated; shape; consolidation; minimize; deleterious; growth; harmful; properties; thermodynamically stable; base alloy; stoichiometric amounts; metallic glass; alloy composition; earth elements; rare earth-iron; grain boundaries; composition comprising; permanent magnet; elevated temperature; transition metal; rare earth; grain size; metal selected; grain growth; magnetic properties; stoichiometric amount; stable compound; earth element; rapidly solidified; substantially amorphous; magnetic phase; nitride grain; dynamically stable; /148/75/419/