Microstructural and magnetic investigations into the origins of high coercivity in die-upset praseodymium{endash}cobalt{endash}carbon based magnets
- Materials Science Division, Department of Applied Science, Brookhaven National Laboratory, Upton, New York 11973 (United States)
Melt-quenched and thermomechanically deformed samples with the nominal compositions Pr{sub 18}Co{sub 82}, Pr{sub 18}Co{sub 81}C, and Pr{sub 18}Co{sub 76}C{sub 6} were examined with optical and electron microscopy, differential thermal analysis, and superconducting quantum interference device magnetometry that was performed in the temperature range 20 K{le}{ital T}{le}300 K. At room temperature, Pr{sub 18}Co{sub 82} exhibits poor coercivity and remanence, 600 Oe and 2.9 kG, respectively. Pr{sub 18}Co{sub 81}C exhibits relatively superior remanence, 7.7 kG, but poor coercivity, 2.7 kOe, while Pr{sub 18}Co{sub 76}C{sub 6} exhibits the opposite trend, {ital B}{sub {ital R}}=4.5 kG and {ital H}{sub {ital ci}}=12 kOe. The main phase present in all samples, PrCo{sub 5}, has basically the same character and morphology for all three samples and shows no evidence of intragranular carbon, which is demonstrated to reside in the impurity phases. The superior coercivity found in Pr{sub 18}Co{sub 76}C{sub 6} is attributed to a previously unknown triclinic phase, Pr{sub 3}Co{sub 4}C{sub {ital x}} ({ital x}{approx_equal}3{endash}4) that appears to undergo a magnetic{endash}nonmagnetic transition with increasing temperature around {ital T}=80 K. The variety of magnetic properties exhibited by each sample is due to the variety of minor phases present in each sample, which may be a product of the effect that carbon has on the solidification rate of the parent alloy. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 256757
- Journal Information:
- Journal of Applied Physics, Vol. 79, Issue 1; Other Information: PBD: Jan 1996
- Country of Publication:
- United States
- Language:
- English
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