| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that it is necessary for a bond magnet to increase an energy product which is a product of magnetization Br and coercive force Hc but if a grain size is made small in order to increase the coercive force, ferrite powder for the bond magnet becomes hard to clog and Br is reduced, and if the grain size is made large in order to increase the magnetization, the coercive force is reduced, such that, in order to increase the energy product, it is necessary to increase both Br and Hc.SOLUTION: Ferrite powder calcined at the temperature of 1050°C to 1300°C under saturation vapor pressure of a chloride is mixed with fine ferrite powder of a small grain size and annealed at the temperature of 800°C to 1100°C, thereby obtaining ferrite powder which has a large grain size and is crystallized beautifully and of which coercive force reduction is a little. A bond magnet produced from the powder has an energy product equal to or more than 2.0 MGOe. |
