An attempt to identify the presence of polytype stacking faults in hBN powders by means of X-ray diffraction

X-ray diffraction techniques have been used to characterize the three-dimensional order and the crystallite size for 17 hBN powders intended to be used as precursors in the cBN synthesis. Six hBN powders (group A) were obtained by the amidic method (borax + urea) purposely for this research and the remaining 11 hBN powders (group B) were commercial products of recognized companies. Attempts have been made to establish linear correlations between the X-ray revealed parameters of the hBN powders. An explanation sustained on experimental basis is proposed for the different linear correlation between the graphitizing index G.I. and order parameter p(3) in the two groups, that points to the existence of polytype stacking faults in hBN depending on the way of fabrication. (C) 2009 Elsevier B.V. All rights reserved.