Permanent magnet and method of manufacturing same

• Main Authors: SHINGAKI YOSHINORI, NAKATSUKA ATSUSHI, ITOU MASAMI, NAGATA HIROSHI, NAKAMURA KYUZO, MUKAE ICHIROU, YOSHIIZUMI RYOU, KATOU TAKEO
• Format: Patent
• Language: English
• Published: 11.09.2012
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; INDUCTANCES; MAGNETS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TRANSFORMERS

There is provided a method of manufacturing a permanent magnet which has an extremely high coercive force and high magnetic properties is manufactured at high productivity. There are executed: a first step of causing at least one of Dy and Tb to adhere to at least part of a surface of iron-boron-rare-earth based sintered magnet; and a second step of diffusing, through heat-treatment at a predetermined temperature, at least one of Dy and Tb adhered to the surface of the sintered magnet into grain boundary phase of the sintered magnet. As the sintered magnet, there is used one which is manufactured by: mixing each powder of principal phase alloy (constituted primarily by R2T14B phase, where R is at least one rare earth element primarily including Nd and where T is a transition metal primarily including Fe), and a liquid phase alloy (having a higher content of R than R2T14B phase and primarily constituted by R-rich phase) in a predetermined mixing ratio; press-forming in magnetic field a mixed powder thus obtained; and sintering a press-formed body in vacuum or inert gas atmosphere.