Investigation for Low-Cost Permanent Magnets.
Annual rept. 1 Jul 80-30 Jun 81,
GENERAL ELECTRIC CORPORATE RESEARCH AND DEVELOPMENT SCHENECTADY NY
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The crystallization of initially amorphous rapidly quenched alloys may provide new materials with good permanent magnet properties at low cost. Preliminary investigations indicate that phosphorus and carbon are favorable alloying elements, and that sudden changes in properties may occur as the identities of the crystallizing phases change. the exploration of alloy systems has been greatly speeded up by the use of current-pulse annealing. It has been found that remanence ratios may be quite high even though the orientation of the crystals formed is probably random. The course of crystallization has been followed by resistance monitoring in conjunction with current-pulse annealing. X-ray diffraction indicates that the highest coercive forces are attained in only partially crystallized samples. Magnetic domain structures have been studied in crystallized ribbons and also in bulk samples of some of the phases observed in them, using both Kerr effect and magnetic colloid. These studies have given useful information about the nature and the magnitude of the magnetocrystalline anisotropy in the phases formed. Alloys containing rare earth elements appear very promising and are being actively pursued. Author
- Electricity and Magnetism