Journal of Materials Science

, Volume 19, Issue 10, pp 3287–3300

Structural components in needle-cokes as studied by etching with chromic acid

Part 1

Authors

  • V. Markovic
    • Institute of Materials Science - 170Boris Kidric Institute, Vinca
  • S. Ragan
    • Northern Carbon Research Laboratories, School of Chemistry, Bedson BuildingUniversity of Newcastle upon Tyne
  • H. Marsh
    • Northern Carbon Research Laboratories, School of Chemistry, Bedson BuildingUniversity of Newcastle upon Tyne
Papers

DOI: 10.1007/BF00549817

Cite this article as:
Markovic, V., Ragan, S. & Marsh, H. J Mater Sci (1984) 19: 3287. doi:10.1007/BF00549817

Abstract

Structures within commercial calcined needle-cokes are characterized by optical microscopy to reveal optical texture and by scanning electron microscopy before and after etching with chromic acid solution at 400 to 423 K. The needle-cokes exhibit an optical texture of medium and coarse-grained mosaics, acicular flow domains and flow domains. The etching studies indicate that the acicular flow domains are made up of rolled and convoluted lamellae which etch to form laths (needle-like) ∼ 3 μm across. The mosaics appear when the rolled structures are viewed microscopically sectioned perpendicular to the lamellae. The acicular flow domains appear in longitudinal section. The etching of the flow domains shows that they have a sedimentary structure, 1 to 2 μm layer thickness, suggesting that mesophase coalesces within a layer but not between layers. A model is proposed to explain the origin and separation of structures in needle-cokes as created in the delayed coker.

Copyright information

© Chapman and Hall Ltd. 1984