MB2-Al2O3 in situ composite powders were synthesized at 1500 degrees C via a novel solid-state precursor route using Group IV-V metal (M, M = Ti, Zr, Hf, Nb, Ta) oxide, Al, and BN as raw materials. As a moderate cost boron source, BN has a well-defined stoichiometry and low impurity. In these precursor powder systems, the TiO2-Al-BN is an exception, which gives rise to the final TiB2-Al2O3-AlN product, whereas the rest produce the diboride-Al2O3 composite powders. As to HiB(2)-Al2O3 and TaB2-Al2O3 composite powders, the diboride phases have a smaller particle size (submicrometer) while the Al2O3 phase possesses a larger size (several micrometers). Besides, these diboride-alumina products produced by the solid-state precursor route form an interwoven network and are intimately mixed on a microscopic scale. (C) 2016 Elsevier B.V. All rights reserved.