The reaction behavior of MoSi2 powder in N2 atmosphere at high temperatures

The reaction behavior of MoSi2 powder in N2 atmosphere between 1573 K and 1873 K was studied in detail. Its phase transition and morphological evolution were investigated by X-Ray Diffraction and Field-Emission Scanning Electron Microscopy, respectively. The results showed that MoSi2 can be transformed to Mo5Si3 and Si3N4 under N2 atmosphere. Many cracks were formed on the surface of particles which made the nitration of MoSi2 much easier. Moreover, a large number of Si3N4 nanorods with a small ball at the tip were formed, and it was concluded that the formation of nanorods obeyed the vapor-liquid-solid mechanism. Finally, the effect of high-temperature preoxidation treatment of MoSi2 on the nitration reaction was studied as well. It was found that a dense SiO2 layer was formed by a high-temperature preoxidation treatment which greatly retards the nitration rate.