| 摘要 |
PROBLEM TO BE SOLVED: To provide a rare earth magnet which is suppressed in the high-temperature demagnetization rate even when heavy rare earth element such as Dy and Tb is reduced in use and not used.SOLUTION: A rare earth element includes RTB main phase crystal grain and a grain boundary phase between the main phase crystal grains adjacent to each other. When the round degree of the main phase crystal grain is evaluated by the roundness degree (roundness) A of Wadell in an arbitrary cross section of a rare earth magnet, a shape of the main phase crystal grain is controlled so that the roundness degree A becomes equal to or more than 0.24. |
