Crystalline Structure of Pitch Produced by the Carbonization of Coal Tar

摘要

Abstract The carbon structure of coal tar, coal tar pitch, and the α fraction at treatment temperatures up to 1200°C is investigated by X-ray phase and X-ray structural analysis. The following X-ray structural parameters are determined: the longitudinal La and transverse Lc dimensions of the stacks of molecular layers (lamellas); the distance d002 between the lamellas; and the number N of lamellas in each stack. Carbonization is accompanied by ordering of the two-dimensional carbon mesophase structures in three-dimensional packets. The carbon structure of the coal tar, coal tar pitch, and α fraction consists of turbostratic graphite structure and graphite-like phases. The transverse Lc and longitudinal La dimensions of the stacks formed by the lamellas in structuring are around 18–25 ? and 18–63 ?, respectively. The mean distance d002 between the lamellas is 3.46–3.55 ?.