Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making
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.
- Research Organization:
- Iowa State University
- DOE Contract Number:
- W-7405-ENG-82
- Assignee:
- Iowa State Univ. Research Foundation, Inc., Ames, IA (United States)
- Patent Number(s):
- US 5,486,240/A/
- Application Number:
- PAN: 8-232,837
- OSTI ID:
- 187083
- Country of Publication:
- United States
- Language:
- English
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