RARE EARTH-IRON-NITROGEN SYSTEM ALLOY MATERIAL, METHOD FOR PRODUCING RARE EARTH-IRON-NITROGEN SYSTEM ALLOY MATERIAL, RARE EARTH-IRON SYSTEM ALLOY MATERIAL, AND METHOD FOR PRODUCING RARE EARTH-IRON SYSTEM ALLOY MATERIAL

摘要

Provided are: a rare earth-iron-nitrogen system alloy material which is capable of providing a rare earth magnet having excellent magnetic characteristics; a method for producing the rare earth-iron-nitrogen system alloy material; a rare earth-iron system alloy material which is suitable as a starting material for the rare earth magnet; and a method for producing the rare earth-iron system alloy material. A rare earth-iron system alloy powder is heat-treated in a hydrogen-containing atmosphere, thereby forming a multiphase powder (1) wherein phases (3) of a hydrogen compound of a rare earth element are present in a discrete manner in a phase (2) of an iron-containing material. A powder compact (4) that is obtained by compressing the multiphase powder (1) is heat-treated in a vacuum, while applying a magnetic field of 3 T or more thereto, so that a rare earth-iron system alloy material (5) is formed. The rare earth-iron system alloy material (5) is heat-treated in a nitrogen atmosphere, while applying a magnetic field of 3.5 T or more thereto, so that a rare earth-iron-nitrogen system alloy material (6) is formed. The rare earth-iron system alloy material (5) has a structure wherein crystals of the rare earth-iron system alloy are oriented in the c-axis direction. By nitriding the rare earth-iron system alloy material (5) having the oriented structure, while applying a magnetic field thereto, the rare earth-iron-nitrogen system alloy material (6) is configured of an ideal nitride, and thus a rare earth magnet (7) having excellent magnetic characteristics can be obtained.