Theory of point-defects, non-stoichiometry, and solute additions in SmCo{sub 5+x}-Sm{sub 2}Co{sub 17{minus}y} and related compounds
There is considerable interest in the possibility of producing Sm-Co-based nanocomposite magnets by rapid solidification and other far-from-equilibrium processing methods. Thermodynamic and kinetic models are quite valuable in understanding and optimizing such methods. This paper describes a method of estimation, utilizing tight-binding-based bond-order interatomic interaction potentials, of the thermodynamic properties of point defects such as vacancies, interstitials, antisite defects, and solute additions in the SmCo{sub 5+x} and Sm{sub 2}Co {sub 17}-y phases and related rare-earth-transition metal compounds. Illustrative calculations for point defects in SmCo{sub 5} will be presented. The results suggest a unified model of the thermodynamic properties of the SmCo{sub 5+x} -- Sm{sub 2} Co{sub 17{minus}y} region of the phase diagram, based on the 1-5 structure and the replacement of Sm by interacting dumb-bell interstitials to form the 2-17 structure; the model is similar in nature to theories of the thermodynamics of metal hydrides.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 10386
- Report Number(s):
- BNL-65210; KC02010300; R&D Project: AS012MSD; KC02010300; TRN: US0103534
- Resource Relation:
- Conference: FIFTHTEENTH INTERNATIONAL WORKSHOP ON RARE EARTH MAGNETS AND THEIR APPLICATIONS, DRESDEN (DE), 08/30/1998--09/03/1998; Other Information: PBD: 3 Sep 1998
- Country of Publication:
- United States
- Language:
- English
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