Influence of grinding on graphite crystallinity from experimental and natural data: implications for graphite thermometry and sample preparation

摘要

This paper examines the effects of shear stress on the structural parameters that define the ‘crystallinity’ of graphite. The results show that highly crystalline graphite samples ground for up to 120 min do not undergo detectable changes in the three-dimensional arrangement of carbon layers but crystallite sizes (L_c and L_a) decrease consistently with increasing grinding time. Grinding also involves particle-size diminution that results in lower temperatures for the beginning of combustion and exothermic maxima in the differential thermal analysis curves. These changes in the structural and thermal characteristics of graphite upon grinding must be taken into account when such data are used for geothermometric estimations.