| 摘要 |
PURPOSE:To contrive improvement in lubricity and releasability between a permanent magnet body, a punch and a metal mold by a method wherein BN powder is arranged between the permanent magnet body, the punch and the contact surface of the metal mold. CONSTITUTION:BN(boron nitride) powder 2 is arranged between a punch 3 and the contact surface of a metal mold when a permanent magnet, having magnetic anisotropy obtained by performing hot plastic deformation on a rare earth-iron-boron alloy, is formed. The BN powder is used as a lubricating agent and a releasing agent for the permanent magnet 1, the punch 3 and the metal mold. Besides, as the above-mentioned BN, a liquid formed by dissolving BN powder into an organic solvent is coated or a spraying method is adopted, and the use of the BN powder mixed with glass powder and carbon powder is effective. As a result, a permanent magnet, having no cracks, chips and exfoliation, of high magnetic characteristics can be obtained. The above- mentioned method is particularly effective in a superflat magnet and a ring- shaped magnet. |
