Synthesis of polycrystalline γ-AlON powders by novel wet chemical processing

The synthesis of polycrystalline aluminum oxynitride (AlON) powders was investigated by the carbothermal reduction and nitridation (CRN) of amorphous precursor obtained by wet chemical processing. Co-precipitation processing was employed to achieve amorphous precursor from Al(NO3)3 solution dispersed by nanosized carbon particles, which was composed of Al(OH)3 and C particles homogeneously. The effects of the content of carbon black, pH value, and calcination temperature on formation of AlON phase were investigated by means of XRD, SEM and TEM, respectively. It was found that single phase AlON powder could be synthesized when the resultant precursors were calcined at 1750°C for 2 hours under flowing N2. Under optimal additional content of C (5.6wt%), the resultant AlON powders exhibited the primary particle size of about 1–3 μm with a specific surface area of 3.2 m2/g, which were superior to that of carbothermal reduction of immediate mixture of γ-Al2O3/C powders.