In this paper, (Ca + Yb)- and (Ca + Sr)-stabilized alpha-SiAlON powders were fabricated by combustion synthesis. The influence of Ca2+ incorporation on the phase composition and grain morphology of combustion products was discussed. The experimental results showed that with the incorporation of Ca2+ well-developed rod-like (Ca + Yb) alpha-SiAlON crystals could be produced. It was also found that, when only Sr2+ was used as stabilizing cation, the reaction product was (alpha + beta)-SiAlON composite, in which beta-SiAlON was the predominant phase and the relative content of alpha-SiAlON was low. With the incorporation of Ca2+, however, both the relative content and the lattice parameters of alpha-SiAlON were clearly increased. These results indicated that the incorporation of Ca2+ could assist Sr2+ into the alpha-SiAlON lattice structure. (c) 2005 Elsevier Ltd. All rights reserved.