Hexagonal boron nitride(hBN) single crystals were grown using a Ni-Cr flux growth method. The crystallization cooling rate, soak temperature and soak time were controlled to determine their effect on crystal size and quality. A cooling rate of 2 degrees C/h produced the best quality hBN crystals. The maximum crystal width increased with soak temperature from 1 mm at 1450 degrees C to 5 mm at 1700 degrees C. The crystal thickness decreased with soak temperature from 500 mu m at 1500 degrees C to 40 mu m at 1700 degrees C. A soak time of 24 to 48h produced the maximum crystal thickness. X-ray diffraction and Raman spectroscopy confirmed that the crystals were highly ordered and of high purity. (C) 2013 Elsevier B.V. All rights reserved.