A thermodynamic study of the HDDR conditions in the Sm2Fe17Nx compound

This paper describes the relationship between hydrogen pressure and temperature ( P-T curve) in the HDDR treatment of the SM2Fe17 compound. The P-T curve suggested that the HDDR condition of the SM2Fe17 compound is more sensitive to temperature than that of the Nd2Fe14B compound. It was also found that the HDDR treatment of the Sm2Fe17 compound has to be controlled in the hydrogen pressure range of one order lower than that of the Nd2Fe14B compound. because of its lower optimum HDDR temperature. Using the P-T curve, new HDDR treatments named v-HD and s-DR, were carried out in order to induce anisotropic feature. However, the normalized remanence of the new HDDR treated powders was around 0.52, which suggested that the powders were almost magnetically isotropic.