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


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.


Heat Treatment Cobalt Pyrolysis Saturation Magnetization Coercive Force 
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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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