Several TEM-based methodologies were developed in order to extract pertinent textural and nanotextural parameters that can ultimately relate to the mechanical behavior. Meanwhile, thorough multi-wavelength Raman (supported by XRD) studies of a CVD-prepared pyrocarbon series along with a coke series as reference samples brought a new insight to the discrimination between various anisotropic pyrocarbons. The study generates a significant progress in the understanding of the D band. It also proposes a much more accurate alternative to the well-known Tuinstra-Koenig law used since 1970 to estimate domain sizes in carbon materials by using the G band width variation.
Plot of the Half-Width at Half-Maximum for the G band (at 1.94 eV) versus the graphene domain size La. Red squares are for cokes and blue diamonds are for pyrocarbons. The slope change corresponds to the beginning of the turbostratic to graphitic structural transformation.