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

ABSTRACT

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.

KEYWORDS:

• Coal-based graphite
• deformation
• graphitization
• nanostructure
• crystallization

Acknowledgments

This study was financially supported by the Performance Incentive Program of Scientific Research Institution of Chongqing (Grant No. cstc2020jxjl0117) and the Science and Technology Major Project of Shanxi (Grant No. 20191102002). We are particularly grateful for the anonymous reviewers for providing useful suggestions and comments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Science and Technology Major Project of Shanxi [20191102002]; Performance Incentive Program of Scientific Research Institution of Chongqing, China [cstc2020jxjl0117].

Notes on contributors

Lu Wang

Lu Wang, graduated from  China University of Mining and Technology (Beijing) with a PhD in 2020, majoring in coal-based graphite and graphene.

Ruigang Zhang

Ruigang Zhang is a project engineer in Chongqing Institute of Geology and Mineral Resources.

Jinhua Luan

Jinhua Luan is a project engineer in Chongqing Institute of Geology and Mineral Resources.

Daiyong Cao

Daiyong Cao is a professor in  China University of Mining and Technology (Beijing).