Mechanochemical Processing of Nanocrystalline Zirconium Diboride Powder

Nanocrystalline ZrB2 powder was prepared by mechanochemical processing of a zirconium (II) dihydride-boron mixture with subsequent annealing from 800 degrees C to 1200 degrees C. The crystallite size and morphology of the synthesized ZrB2 powders were characterized by X-ray diffractometry, scanning electron microscopy, and transmission electron microscopy. The effects of annealing temperature on powder particle size and morphology were assessed. At 900 degrees C or above, pure ZrB2 powder was obtained without trace quantities of residual ZrH2. The synthesized ZrB2 powder particles were spherically shaped, with a crystallite size between 5 and 40 nm. The crystallite size increased with increase of annealing temperature.