Low-energy ball-milling : Transformations of boron nitride powders. Crystallographic and chemical characterizations

BN powders (with and without water) which have undergone low-energyball-milling have been studied through X-ray diffraction,transmission electron microscopy, granulometry, electron energy loss(EELS) and IR spectroscopies. The main result is the formation of theorthorhombic and cubic high pressure phases of BN. A “turbostratic”behaviour of hexagonal BN has also been observed. As expected, thegrain sizes decrease markedly. It is to be noticed that the presenceof water induces some chemical reactions which are revealed throughammonia-like and nitride compounds scents. However, according to EELSmeasurements, the main transformations are structural ones.