Phenomenes d'interaction entre divers carbones au cours des traitements thermiques

Abstract

Previous observations of the presence of an interaction between binders and fillers at high temperature are confirmed by new studies. Various products made from combination of two binders (coal pitch, thermosetting resin) and six fillers (natural graphite, petroleum coke, carbon black, etc.) have been used. The interaction was demonstrated using optical microscopy, X-ray diffraction and oxidation in a liquid medium, and by comparing the results obtained for the initial products and the bound materials all treated to high-temperature. Since the proportion of binder in the mixture was in some cases not sufficient for the interaction to be observable by X-ray diffraction, new mixtures were prepared using similar basic materials but with increased proportion of binder. With these new products the results found by X-ray diffraction confirm, qualitatively at least, those obtained by wet oxidation: an interaction, sometimes positive and sometimes negative, is observed. For materials from highly graphitisable products, the X-ray diffraction turns out to be a more sensitive method than oxidation in liquid medium. Optical microscopy provides interesting observations on the behavior of the respective components of the mixture. A tentative interpretation of the interaction phenomena is put forward.