Phase Decomposition of FexN Compounds under High Pressures

The effect of pressure on the decomposition of compounds FexN at room temperature has been investigated X-ray diffraction analysis shows that high pressure prompts nitrogen atoms precipitating from the lattice of FexN compounds, causing phase decomposition and forming parent phase and -Fe. This phenomenon increases with increasing pressure. Dynamic process of nitrogen precipitation and the activation volume in FexN have been investigated by analyzing the relative content of -Fe in the parent phase FexN. The activation volume of Fe3N and Fe4N are 2.2410-5 m3/mol and 1.6210-5 m3/mol, respectively. The Fe16N2 compound can be obtained at appropriate condition by annealing the FexN compounds which have been compacted under high pressure.