2021 Volume 62 Issue 731 Pages 183-189
High-pressure compaction was investigated as a consolidation technique for the fabrication of high-density Zn/samarium-iron-nitrogen (Sm-Fe-N) bulk magnets. To achieve a relative density (dr) above 90.0% in Zn/Sm-Fe-N bulk magnets, we examined the compaction characteristics of Zn/Sm-Fe-N powders within a compaction pressure range of 1.5 to 4.1 GPa, which have not been sufficiently investigated. Furthermore, the effects of compaction pressure and Zn addition on dr were investigated at various concentrations of Zn, and various compaction conditions were evaluated mainly based on the resulting dr. The dr exceeded 90.0% under a pressure of 3.5 GPa in warm compaction at 200 ℃, and significant die breakage was suppressed. The proposed compaction conditions are more suitable for mass production in the vehicle industry than those of conventional techniques. Combining the proposed compaction conditions with 10 wt% Zn, the magnetic properties of the fabricated Zn/Sm-Fe-N bulk magnet show a remanence (Br) of 0.79 T, which represents the residual magnetic flux density, and a coercivity (HcJ) of 1163 kA·m-1, which is an index of the heat resistance of the magnets.
