Preparation of ultrafine InN powder by the nitridation of In2O3 or In(OH)3 and its thermal stability

Crystalline InN powder has been prepared by the nitridation of In2O3 and In(OH)(3) with NH3 gas for the first time, and ultrafine InN powder in the size range 50-300 nm and with a specific surface area of 8 m(2) g(-1) has been obtained using In2O3 nanoparticles as the starting material. The resulting powders were characterized by XRD, FE-SEM, TEM, TG-DSC and BET surface area techniques. It was found that nanosized In2O3 was completely converted into InN at 600 degreesC within 8 h. The thermal stability of the ultrafine InN powder in air and under a nitrogen atmosphere was also investigated. It was observed that InN began to be oxidized into In2O3 at 389 degreesC and decomposed in the narrow temperature range of 595-696 degreesC in flows of air and N-2, respectively.