Ultrafine magnetic metal dispersed carbons prepared from anisotropic pitch and metal acetylacetonate complexes

Abstract

Transition metal (Fe, Co or Ni) dispersed carbon composites were prepared using the mixtures of metal acetylacetonate complex as a source of metal particles and an anisotropic coal-tar pitch as a carbon matrix precursor by heat treatment at the temperatures up to 1000°C. Mixing of the metal complexes and the pitch by dissolving in quinoline permitted the notable fine dispersion of the complex in the pitch. Then the resulting mixtures were easily converted to the metal dispersed carbons by pyrolysis under an inert atmosphere. The appeared particles were Fe₃O₄/α-Fe/Fe₃C, β-Co or Ni when using the corresponding metal complex. Besides, their particle diameters were much less than 30 nm and distributed evenly throughout the carbon matrix. The magnetic properties of the metal dispersed carbons were evaluated with a vibrating sample magnetometer, and it was found that saturation magnetization and coercive force ranged from 1.03 × 10⁻⁵ to 5.65 × 10⁻⁵ Wb · m/kg and from 0.21 × 10⁴ to 3.06 × 10⁴ A/m, respectively.