title: Formation mechanism of Si3N4 nanowires via carbothermal reduction of carbonaceous silica xerogels.
abstract: Si3N4 nanowires prepared from the carbothermal reduction of carbonaceous silica xerogels with metal salt additives usually contain a small amount of nanotubes. This paper is devoted to the investigation of the formation mechanism of the Si3N4 nanowires. As-prepared samples heated at 1300 degrees C for different reaction times (1, 5, 10, and 30 h) were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The results showed that all the samples mainly consisted of nanowires, while their crystalline phases changed with the heating time. Nitrogen-doped silicon oxide nanowires were first produced via the vapor-liquid-solid process and then underwent a stepwise surface nitrogenization to silicon nitride. The suggested mechanism can easily explain the existence of nanotubes in the Si3N4 nanowires.
authors.affiliation: State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Taiyuan 030001, China, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Jin
authors.forename: Xiang-Yun
authors.initials: XY
authors.lastname: Guo