Graphite to diamond-like carbon phase transformation by high-pressure torsion

Diamond-like carbon (DLC) with significant fraction of tetrahedral sp(3) bonds and amorphous structure is generally produced in the form of thin films by rapid cooling of high-energy carbon atoms in vacuum. This study shows that DLC can be directly formed from bulk samples of graphite by application of severe plastic deformation under high pressures. The formation of DLC is enhanced with increasing the shear strain, pressure, and temperature. It is suggested that the high pressure thermodynamically stabilize DLC and formation of high density of lattice defects by straining reduces the energy barrier for DLC formation. (C) 2013 AIP Publishing LLC.