Synthesis of Monolithic β-Sialon Powders (Si6−zAlzOzN8−z, Z = 2−4) through Controlling the Combustion Reaction Temperature

Abstract

Pure β-sialon powders with the controlled z values (z = 2− 4) were successfully prepared from stoichiometric mixtures of constituent elements (Si, Al and SiO2) under a nitrogen pressure of 1 MPa by the combustion synthesis (CS) method. The raw materials were combusted with different ratios of a commercial sialon powder of z = 1 as a diluent (0, 10, 20, 30, 40, 50 wt %). Without diluent, the reactions temperatures were very high (> 2000 °C) and the product contained metal Si residue besides Sialon products. The combustion temperatures of nitridation reactions were controlled by using Sialon (z = 1) as a diluent. The combustion reactions completed at 50 wt% dilution, and pure β-sialon phases were synthesized. However, the individual peaks of β-Sialon (z = 1) diluent were also detected. Single-phase β-sialon powders were obtained by using the products as diluents and repeating the combustion for few times.