PHASE TRANSITIONS OF C70 FULLERITE UNDER STEP-LIKE SHOCK COMPRESSION

Shock-induced phase transitions of C70 fullerite with hexagonal close-packed structure were experimentally studied with use of recovery assemblies of planar geometry at pressures 8 to 36 GPa. It was found that C70 fullerite undergoes a series of polymorphic transitions in conditions of step-like shock compression. Hexagonal close-packed structure of C70 fullerite remained practically unchanged at shock pressure 8 GPa. Shock-induced transformation of the hexagonal structure into face centered cubic structure was fixed at pressures in the range 8 to 23.5 GPa. Depth of this transformation was increasing with growth of shock pressure. With further growth of shock pressure the destruction of C70 molecules occurs. This destruction is accompanying with a formation of graphite-like carbon.