α″-Fe16N2 nanopowder was sintered at high-pressure and low temperature in order to explore its feasibility as a bulk magnet. TEM observation confirmed that the nanopowder was densely consolidated by sintering at a pressure of 1.2 GPa and temperatures around 200 C. Increasing the sintering temperature enhanced the densification, leading to a suppression of oxidization. However, XRD analysis revealed that sintering at 222 C caused the decomposition α″ → α-Fe + ε-Fe3N, which reduced the saturated magnetization (Ms) and coercivity (H c). Consequently, sintering at 190 C produced a dense magnet that retained the Ms of the raw powder due to the avoidances of oxidization and decomposition. On the other hand, it was found that H c degrades after sintering, which is believed to be due to magnetic interaction between the particles.
ASJC Scopus subject areas
- Physics and Astronomy(all)