Growth mechanism and synchronous synthesis of 1D β-sialon nanostructures and β-sialon-Si3N4 composite powders by a process of reduction nitridation

Nanostructure reinforced nitride ceramics play an important role in the family of structural ceramics. In this study, large scale of one-dimensional (1D) β-sialon nanostructures and β-sialon-β-Si3N4 composite powders were synthesized simultaneously via a reduction nitridation process by using powders of silicon, aluminum, and silica as raw materials. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM/HRTEM), Fourier-transform infrared spectroscopy (FT-IR) and energy dispersive x-ray spectroscopy (EDS) were used to characterize the phase composition, morphology, and microstructure of the as-obtained products. As a result, large scale of 1D β-sialon nanostructures can be prepared at 1600 °C. The diameter of the as-prepared nanowires in the range of 80 to 170 nm can be tailored by the addition of aluminum. The growth of 1D β-sialon nanostructures is achieved by a vapor-solid (VS) mechanism. Photoluminescence (PL) of the 1D β-sialon nanostructures was characterized which exhibit violet/blue emission peaks, making it have the potential to be applied in optoelectronic nanodevices. Besides, nitride ceramic composite powders including β-Si3N4 and β-sialon with in situ formed β-sialon nanowires were also achieved. The phase transformation behavior and the thermodynamical analysis of the ceramic composite powders were also studied by characterizing the phase composition of the products synthesized at different temperature. The as-grown β-sialon nanowires and the composite powders have great potential to be applied in nanostructure reinforced structural ceramics.