Sulfur-assisted synthesis of nitridenanocrystals

Abstract

A series of nitrides (TiN, ZrN, BN, AlN) were prepared by using the corresponding elements (Ti, Zr, B, Al), NaN₃ and sulfur as starting materials in a stainless steel autoclave at 250 °C. Sulfur was used to facilitate the exothermic reaction between NaN₃ and sulfur (at 250 °C) and the final formation of nitrides. The treatment temperature affected the growth of the nitride crystals, for example, diversified morphologies of TiN nanocrystals were formed in different temperature ranges: grain and truncated octahedron (250 °C), octahedron (>300 °C), and dendrite (>400 °C). Through similar processes, other nitrides (for example, TiN, AlN, Si₃N₄) could also be produced by employing NaNH₂ and additives (such as iodine or N-aminothiourea instead of sulfur) in low temperatures.