High-Pressure Coupling Reactions to Produce a Spherical Bulk Re x N/Fe 3 N Composite.

We report a novel high-pressure coupling (HPC) reaction that couples the nitridation of Re with high-pressure solid-state metathesis (HPSSM) of Fe 3 N to produce a spherical bulk Re x N/Fe 3 N composite. Compared with conventional methods, upon coupling of the HPSSM reactions, the synthetic pressure for Re nitridation was successfully reduced from 13 to 10 GPa (for Re 3 N) and from 20 to 15 GPa (for Re 2 N). The product Re x N species would be surrounded by product Fe 3 N, resulting in a spherical bulk Re x N/Fe 3 N composite ( x = 2 or 3). The composite exhibits a soft magnetic behavior, and the content of nitrogen in Re x N ( x = 2 or 3) was controlled by adjusting the P-T conditions. The HPC reaction establishes a new approach for the bulk synthesis of 5d transition metal nitride.