| 摘要 |
PURPOSE:To enable a composite magnet with high magnet characteristics to be obtained from a homogenized single-phase magnet powder, by heat-treating an R2T17 ingot at a temperature at which a liquid phase is present prior to a solid solution treatment. CONSTITUTION:In a manufacture of a rare earth cobalt polymer composite magnet in which, after an ingot of an R2T17 magnet alloy (wherein R is at least one selected from among yttrium and rare earth elements, and T is at least one selected from among transition metals including Co as a principal component) has been subjected to a solid solution treatment and aging, it is powdered, and this powder and a polymer resin are mixed and formed into a magnet, the R2T17 ingot is heat-treated at a temperature at which a liquid phase is present prior to the solid solution treatment. For example, the ingot is first heat-treated for 2hr at each of the temperatures of 1,180, 1,190, 1,200, 1,210 and 1,220 deg.C and is subsequently held for 2hr at 1,180 deg.C which is an optimum solid solution treatment temperature for this alloy, and is then quenched. This ingot is held at 800 deg.C for 1hr and is then cooled at 1 deg.C/min so as to be aged. The ingot subjected to the above heat treatment is powdered by a ball mill so that an average particle diameter is 10mum. After 7wt% of nylon 12 has been added to and kneaded with the magnet powder, this is injection-molded at a high temperature and in a magnetic field of 15kOe. |
