Raman microspectroscopy characterization of carbon blacks: Spectral analysis and structural information

The aim of this paper is to describe carbonisation and partial graphitization of carbon blacks (CB). Raman spectrometry is used to investigate a series of five CB grades during heat treatment (up to 2600 °C). Obtained results are discussed by comparing Raman data with X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) observations. For Raman spectra interpretation, the usual curve fitting method proposed by Sadezky et al. for soot and disordered carbonaceous material is applied. As the same procedure can be applied over all the heat-treatment temperature range, the determination of band parameters from five band decompositions appears to be the most convenient to follow the CB's structural improvement. We demonstrate that only a partial graphitization takes place and the graphitizability is limited by the diameter of the primary particles. Our observations generalize the results obtained for cokes: graphitization degree of carbonaceous materials after the heat-treatment is limited by the diameter of the volumes within polyaromatic layers are oriented in parallel.