Large-scale synthesis of ear-like Si3N4 dendrites from SiO2/Fe composites and Si powders

Large-scale ear-like Si3N4 dendrites were prepared by the reaction of SiO2/Fe composites and Si powders in N2 atmosphere. The product was characterized by field emission scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The results reveal that the product mainly consists of ear-like Si3N4 dendrites with crystal structures, which have a length of several microns and a diameter of 100–200 nm. Nanosized ladder-like Si3N4 was also obtained when changing the Fe content in the SiO2/Fe composites. The Si3N4 nanoladders have a length of hundreds nanometers to several microns and a width of 100–300 nm. The ear-like Si3N4 dendrites are formed from a two-step growth process, the formation of inner stem structures followed by the epitaxial growth of secondary branches.