Abstract: | Alpha phase silicon nitride (α-Si3N4) powders were synthesized by combustion reaction of the in-situ nano-SiO2 coated Si and Si3N4 reactants with pressurized nitrogen. The combustion temperature profile as well as the product phase composition and morphology were investigated. Regardless of the combustion temperature reached as high as 1800 °C, up to 86 wt% α-Si3N4 was obtained in the combustion-synthesized product from the reactants with only 6 wt% SiO2 addition, which is three times higher than that of without SiO2 coating, meanwhile, the morphology of Si3N4 grains changed from rod-like to equiaxed grain,indicating the in-situ coated SiO2 tailored the nitridation reaction path of Si successfully by enhancing the silicon monoxide (SiO) gas phase formation. |