| 摘要 |
PURPOSE:To improve both magnetic characteristics and machinability by a method wherein magnetic alloy powder is heated in a temperature range where the crystal structure assumes 2-17 type high temperature phase, cooled fast at a specific condition and then subject to age processing. CONSTITUTION:A magnetic alloy containing cobalt and at least one kind of rare-earth element is pulverized to powder or small granules with grain size of 3-4,000mum. These powder or small granules are heated in a temperature range where the crystal structure thereof assumes 2-17 type high temperature phase such as TbCu7 or Th2Ni17 type, and then cooled fast down to below the room temperature at a cooling rate not less than 1,000 deg.C/min. After subsequent age processing in a temperature range of 350-900 deg.C, these powder or small granules are made into fine particles, arrayed magnetically and then subject to press forming. By so doing, it becomes possible to obtain a permanent magnet which is superior in magnetic characteristics, mechanical machinability as well as thermal shock resistance, even with high Fe composition ratio. |
