Morphology control of β-SiAlON via salt-assisted combustion synthesis

A facile salt-assisted combustion synthesis of β-SiAlON and systematic characterization of the endothermic effects of addition of KCl, MgCl2, and CaCl2 were investigated under a nitrogen pressure of 1 MPa. Single-phase products containing crystals with different shapes were obtained. The results indicated that the metal chlorides act as perfect diluents that effectively absorb the reaction heat via their melting and evaporation, which occur in the same temperature ranges as the two stages of the exothermic processes. In addition, the products exhibited different morphologies when the type or amount of metal chlorides was changed. The results of this work suggest that single-phase β-SiAlON could be fabricated with the intended morphology by simply adding different kinds of metal chlorides.