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.