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Journal of Materials Science

, Volume 21, Issue 6, pp 1951–1955 | Cite as

Synthesis and properties of carbons dispersed with Fe-Co alloy by pressure pyrolysis of organoiron-organocobalt copolymer

  • Shin -Ichi Hirano
  • Toshinobu Yogo
  • Kō -ichi Kikuta
  • Shigeharu Naka
Papers

Abstract

Carbons dispersed with Fe-Co alloy were synthesized by the pressure pyrolysis of vinylferro cene-phenylethynylcobaltocene-divinylbenzene copolymer at temperatures below 700° C and at 125 M Pa. As-prepared carbon synthesized at 550° C contained finely dispersed metallic particles of less than 10nm diameter with low crystallinity, which crystallized to form Fe-Co alloy particles with a higher crystallinity by subsequent heat treatment at 800° C. Larger particles of the alloy of more than 50nm diameter were dispersed in the carbon matrix synthesized at 700° C. Thermomagnetization measurement of the as-prepared carbon synthesized from divinylbenzene-2.1 mol% vinylferrocene-4.8mol% phenylethynylcobaltocene copolymer at 550° C and 125 M Pa confirmed that iron formed an alloy with cobalt in the carbon matrix. Fine, superparamagnetic metallic particles in the as-prepared carbon aggregated and crystallized by the heat treatment during the thermomagnetic measurement to increase the magnetization of the alloy-dispersed carbon. The saturation magnetization and the coercive force of alloy-dispersed carbon increased from 128 to 187e.m.u.g−1 and from a few to 50 Oe, respectively, on increasing the pyrolysis temperature of the starting copolymer from 550 to 700° C. The saturation magnetization of alloy-dispersed carbon from divinylbenzene containing iron and cobalt with a ratio of 5∶2 was higher than that from divinylbenzene including those with a ratio of 2∶5. The carbon with finely dispersed Fe-Co alloy showed a high saturation magnetization of 213 e.m.u.g−1 and a coercive force of 230 Oe, and the magnetization persisted above 800° C.

Keywords

Heat Treatment Cobalt Pyrolysis Saturation Magnetization Coercive Force 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman and Hall Ltd. 1986

Authors and Affiliations

  • Shin -Ichi Hirano
    • 1
  • Toshinobu Yogo
    • 1
    • 2
  • Kō -ichi Kikuta
    • 1
    • 2
  • Shigeharu Naka
    • 1
    • 2
  1. 1.Department of Applied ChemistryNagoya UniversityNagoyaJapan
  2. 2.Synthetic Crystal Research Laboratory, Faculty of EngineeringNagoya UniversityNagoyaJapan

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