Structural evolution of hexagonal BN and cubic BN during ball milling

The structural evolution of hexagonal boron nitride (h-BN) and cubic boron nitride (c-BN) during ball milling has been studied by means of X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IRS) and differential scanning calorimetry (DSC). It is found that the grain size of h-BN decreased remarkably with increasing milling time but grew larger during annealing. h-BN was refined significantly during ball milling and a turbostratic rather than amorphous structure could be induced by ball milling as it proceeded. c-BN only acted as an abrasive without obvious refinement all over the ball milling due to its super hardness.