| 摘要 |
PURPOSE:To prevent oxidation/deterioration of a magnet during manufacturing or use by forming a fine oxidation-resistant surface coating by forced oxidation of magnetic particle surfaces of an intermetallic compound. CONSTITUTION:A passivation agent is brought into contact to intermetallic compound magnetic particles base of which is a rare earth metal expressed in R-Fe-B (R is Nd and/or Pr, or a part thereof is replaced with one or more types of rare earth elements) and transition metals. A passivation coating is thereby formed over the magnetic particle surfaces. The base of a compound is immobilized coating forming magnetic particles and a synthetic resin as a binder. After the compound is compression molded, a molding is completed by curing the binder. As the passivation agent, it is desirable to use one or more than two of chromic acid, bichromate, nitric acid, permanganic acid, nitride, permanganate, molybdate and tungstate. |
