| 摘要 |
PURPOSE: To obtain a high corrosion-resistant permanent magnet which is much enhanced in corrosion resistance by a method wherein a glassy protective layer is provided onto the surface of an R-Fe-B permanent magnet which is liable to deteriorate in magnetic properties due to oxidation. CONSTITUTION: An R-Fe-B permanent magnet (R denotes one of rare earth elements including Y) is dipped into treatment solution of alkaline silicate water solution or treatment solution is applied onto the magnet, and then the magnet is heat-treated, whereby the surface of the permanent magnet is coated with a glassy protective layer as thick as 5nm to 10μm. Or the surface of a permanent magnet is subjected to an ultrasonic rinsing pretreatment before the permanent magnet is dipped into treatment solution. |
