THERMAL ANALYSIS OF PRESSED GRAPHITE

Abstract

The samples studied are pure graphite whose preparation method includes a step of pressing. Graphite is a material with properties covering a wide range of values. These properties may differ qualitatively, and depending on the material source and also the process of its development. Graphite is characterized by a dense stacked layered structure but weakly linked. Graphite polycrystalline properties are often isotropic, because of the random orientation of grains. Recently, it has been developed processes of production that have resulted in macroscopic samples that exhibit anisotropic properties. Therefore, the scope of use of this material has become very large. The pressed graphite has an anisotropic expansion behavior. Whether the pressing in the direction of strong bonds (basic plan) or the weak links, the behavior of our samples is characterized by an anisotropy that is not found in pure graphite that was used as a reference. The anisotropy established in the pressed samples is due to the presence of a preferential orientation of the grains in the polycrystalline graphite. The analysis of DSC curves of our samples allowed us to highlight an acceleration of the kinetics of the reaction identified in single graphite in the temperature range studied; namely, the dissolution of oxygenated compounds. This acceleration is probably due to the high density of structural defects in our samples, which was also evidenced by XRD analysis. Scanning calorimetry has confirmed the X-ray diffraction analysis