Nanoscale Microscopic Features and Evolution Sequence of Coal-Based Graphite

摘要

X-ray diffraction and transmission electron microscopy were used to obtain a description of the nanoscale microscopic features that change during the graphitization process of coal. We have concluded that the graphitized process of coal has non-uniform features. It undergoes the changes that decrease the rate of d(002) from large to small on the evolution rate, and even the varying particles in the same coal can cause different graphitization degree because of different components in the microenvironments. Parameters of XRD, such as d(002), FWHM, Lc, and graphite degree U-2, can be used to evaluate the degree of a whole graphitized coal. In addition, the graphitized evolution mechanism of coal experiences a transformation from aromatization to condensation, and then making-up action. Each evolutionary stage shows regular changes in the HRTEM and SAED figures. Microstructure evolution sequence of USB isolees, microcoluma graphite, wrinkled graphite, and couches planes were redefined on the basis of (hk0) lattice evolution studies.