| 摘要 |
PURPOSE:To improve a squareness and increase coercive force by executing aging treatment at 850-1,000 deg.C while using a permanent magnet alloy having a special composition as a starting material, conducting cooling up to 400 deg.C or lower at a cooling rate of 100 deg.C/min or more and executing aging treatment at 500-750 deg.C. CONSTITUTION:Oxygen concentration in a permanent magnet alloy has a remark able effect on coercive force in a rare earth iron group permanent magnet. A composition is constituted of a 10-40wt% rare earth element, a 0.1-8wt% boron, a 0.5-5wt% aluminum, a 0.005-0.03wt% oxygen and the remainder mainly consisting of iron on the basis of said phenomenon. Coercive force and a square-shape property-that is, (BH)max-largely depend upon an aging treat ment method. The permanent magnet alloy is employed as a starting material and the alloy is aging-treated at 850-1,000 deg.C, cooled up to 400 deg.C or lower at a cooling rate of 100 deg.C/min or more and aging-treated at 500-750 deg.C on the basis of said phenomenon regarding coercive force and the square-shape property. |
