Phase transition and shock-compression parameters to 120 GPa for three types of graphite and for amorphous carbon

Shock-induced graphite-to-diamond phase transition pressures and Hugoniot parameters to 120 GPa are presented for pyrolytic, Ceylon natural, and synthetic graphites. The response of amorphous carbon to shock loading, including a shock-induced phase transition, is reported. Interpretations of discontinuities found in the shock-velocity versus particle-velocity plots are discussed in terms of the carbon phase diagram. Evidence of a solid-to-solid phase transition from diamond to a metallic state at very high pressure is described