Carbon phase transformations under electrodynamic compression

The graphite-diamond phase transition under shock-wave-induced electrodynamic compression has been studied. A sample of a carbon-containing material was loaded by axisymmetric collapse of a copper liner. The liner was acted upon by ponderomotive forces generated by pulsed electric currents with amplitudes of 2–4 MA. The collapse of the cylindrical copper liner with a velocity of ～1 km/s produced stepped loading of the carbon material in an ampoule from 5 to 40 GPa over 4 µs. Purification of the preserved material yielded agglomerates containing polycrystalline diamond. The average size of diamond polycrystals in the agglomerates is 1–2 µm, and the agglomerate yield is ～3%.