Permanent magnet alloys for gap magnets
Provided are Ce/Co/Cu permanent magnet alloys containing certain refractory metals, such as Ta and/or Hf, and optionally Fe which represent economically more favorable alternative to Sm-based magnets with respect to both material and processing costs and which retain and/or improve magnetic characteristics useful for GAP MAGNET applications.
1 . A heat treated permanent magnet, comprising an alloy comprised of Ce, Co, Cu, and a refractory metal and having a heat treated bimodal microstructure with refractory metal-containing laminas precipitated and dispersed within a single grain matrix or within individual grains of a multi-grain matrix wherein the heat treated microstructure imparts magnetic properties for use as a GAP magnet.
2 . The magnet of claim 1 having an interface between the matrix and the respective laminas wherein the interface has less Cu than the matrix.
3 . The magnet of claim 1 comprising, in atomic %, 13 to 16.6% Ce, 38 to less than 70% Co, 10% to 30 atomic % Cu, 10% to 20% Fe, and one or more refractory metals in an individual or collective amount greater than 0.1% up to 3 atomic %.
4 . The magnet of claim 1 which has been subjected to a solution temperature followed by aging to develop the bimodal microstructure.
5 . The magnet of claim 1 that exhibits a T c >300° C., H c =0.5-1.0 T, B r =4-8 KG and (BH) max .=7-15 MGOe.
6 . The magnet of claim 1 wherein the alloy comprises, in atomic %, 14% to 15.5% Ce, 57.5% to 62.0% Co, 10% to 16.5% Cu, 10% to 12.5% Fe, and one or more refractory metals in an individual or collective amount of 0.5% to 1% atomic %.
7 . The magnet of claim 1 wherein the magnet comprises, in atomic %, 13% to 15.5% Ce, 57.5% to 62.0% Co, 10% to 16.5% Cu, 10% to 13.7% Fe, and one or more refractory metals in an individual or collective amount of 0.5% to 1.3% atomic %.
8 . The magnet of claim 1 wherein the laminas have respective lengths of about 1 micron to about 10 microns and respective thicknesses of about 0.05 micron to about 0.1 micron.
9 . The magnet of claim 1 wherein the refractory metal is selected from the group consisting of Ta, Hf, Zr, Nb, Mo, and W.