Effect of different deformation on the order degree of coal-based graphite

The effects of deformation on the macromolecular structure of low/high rank coals are different from coal-based graphite. These differences are attributed to the order degree of the nanostructure. Brittle-, brittle-ductile-, and ductile deformed coal-based graphite from Lutang mining area, Hunan province, China, was collected and evaluated by the ultimate and proximate analysis, XRD, Raman spectroscopy, and HRTEM analysis. Chemical structure, crystallite, and fringe information were obtained to understand how the different deformation affects the nanostructure. During the graphitization, the nanostructure was less affected by brittle deformation. From brittle to ductile deformation, the crystalline size La seems to reach the peak value and the structural defects largely decrease. Moreover, there was an significant improvement in the structural alignment and decrement of tortuosity. However, for the ductile deformed samples, the stacking was not influenced but La values strikingly decreased. The aromatic layers tend to bend or deform, inducing the breakage of cross-linking. And the orientation of lattice fringes were separated into two directions with a large angular separation of 76.2 ± 7.6°. Furthermore, there was a higher contribution of highly curved fringes. These observations are likely to be a supplement to the traditional understanding of the effect of deformation on the coalification.