▎ 摘　　要

Graphene nanoplatelets were consolidated at various conditions using spark plasma sintering utilizing ON-OFF DC pulse energizing. The phase transformation from graphene nanoplatelets to diamond can occur at pressure of 80 MPa and at temperatures of 1100 degrees C to 1500 degrees C without any catalysts being involved. However, no diamond formation could be observed in sintering experiments at the same pressure-temperature conditions with steady AC heating. Our results indicate that the phase formation of diamond induced by the pulsed DC field was determined by the presence of plasmas in areas of locally increased densities of stacking faults in the layered graphene nanoplatelets under sintering-pressures. (C) 2014 AIP Publishing LLC.