Nitridation of Silica to an α-Silicon Nitride Nanorod Using NaNH2 in the Autoclave at 700°C.

α-silicon nitride nanorods have been synthesized through solid-state reduction–nitridation of silica using NaNH₂ as both a reductant and a nitriding reagent. X-ray powder diffraction patterns show that the products have a hexagonal phase with lattice parameters a=7.767 Å and c=5.630 Å. Transmission electron microscopy reveals that the as-synthesized products are pure nanorods with an average size about 30 nm in diameter and 400 nm in length. X-ray photoelectron spectra indicate that the molar ratio of Si/N is 2.988:4. Fourier-transform infrared spectrum yields a strong Si–N absorption at 926 cm⁻¹ that may be a red shift due to size effect. [ABSTRACT FROM AUTHOR]