Fabrication of AlN particles and whiskers via salt-assisted combustion synthesis

High-quality AlN ceramic particles and whiskers were synthesized via salt-assisted combustion with the addition of AlN and NaCl, KCl, or MgCl2 to the raw Al powders. The experiments were carried out at nitrogen pressures between 0.2 and 1.0 MPa. The results show that 20–30 mass% salt is required to achieve complete nitridation of Al. The sensible and latent heats of these salts afford effective heat absorption during the reaction, which greatly reduces the amount of diluent AlN required compared with the conventional combustion synthesis of AlN. In addition, AlN particles are obtained when NaCl or KCl is added, whereas irregular whiskers are obtained with MgCl2.