Synergistic influence of fluorine and hydrogen on processes of thermal transformations of carbon-containing systems under high pressures

Thermal transformations of naphthalene (C$_{10}$H$_{8}$), octafluoronaphthalene (C$_{10}$F$_{8}$) and their binary mixtures at 8.0 GPa have been investigated by X-ray diffraction, Raman spectroscopy, scanning and transmission microscopies. As a result, the pronounced synergistic effect of fluorine and hydrogen on mechanisms, $p$, $T$ parameters and products of pressure-temperature-induced transformations of carbon-containing systems has been established. Simultaneous presence of fluorine and hydrogen gives rise to significant reduction of the temperature thresholds (TT) for carbonization, graphitization and diamond formation in C$_{10}$H$_{8}$ – C$_{10}$F$_{8}$ mixtures in comparison with the TT values for pure C$_{10}$H$_{8}$ and C$_{10}$F$_{8}$ at the same pressure. This synergistic effect manifests itself also in the simultaneous presence in the products of transformation of both nano- and micrometer-sized diamond fractions. The reasons of formation of different diamond fractions in the products of binary mixture treatment are discussed in this work.