SYNTHESIS OF NANOGRAPHITE BY ELEKTROSPARK DISPERSION AND STUDY OF ITS THERMAL OXIDATION

The paper presents the results of studying the possibility of obtaining nanosized graphite by the method of electrospark dispersion. The formation of nanographite during electrospark dispersion of EUZ-3 grade graphite in distilled water and 95 % ethanol was confirmed by powder X-ray diffraction and transmission electron microscopy.The diffraction patterns of nanographites obtained in water and alcohol are identical, and they have line reflexes that belong to graphite. The nanographites have the same interplanar spacing and lattice parameter. The value of the lattice parameter of nanographites indicates that graphite does not change its structure under the conditions of electrospark dispersion, and nanographites are characterized by a hexagonal crystal lattice. The results of calculating the size of the coherent scattering region and determining the average diameter of particles from TEM photographs confirm the formation of nanographite. More highly dispersed (d CSR = 6.5 nm, d av. = 6±1 nm) nanographite is formed in water than in alcohol (d CSR = 9.8 nm, d av. = 10±2 nm). When analyzing the derivatograms, the dependence of the change in the TG and DTA curves of the derivatograms on the properties of the liquid medium where nanographite was synthesized was established. An analysis of the derivatograms of nanographites shows that the course of the TG and DTA curves of the derivatograms depends on the nature of the liquid medium in which the nanographite was obtained. Oxidation of nanographite obtained in water occurs in three stages in the temperature range of 200–700 °C. When this nanographite is heated to 1000 °C in air, the decrease in the mass of the sample, due to the oxidation of carbon in the form of graphite, is 92.0 %. On the derivatogram, the oxidation of nanographite synthesized in alcohol is characterized by an intense doublet of exothermic effects covering the temperature range of 400–700 °C and the decrease in the mass of the sample is 95.75 %.