The growth of AIN rod-like crystals, successfully produced via direct nitridation of Al-alloy doped with 5 wt% Mg and 2 wt% Si at 1273 K is predominantly based on capillary niass-transfer phenomena, which occur through a network of micro-channels developed in the empty space among the AIN columnar crystals as well as the hollows inside these crystals. The diffusion of N-2 in the liquid alloy is the rate-determining step of the process. Mg and Mg3N, resulting after nitridation maintain a very low partial pressure of oxygen during the entire process and favour the formation of AIN. (c) 2005 Elsevier B.V. All rights reserved.