| 摘要 |
PURPOSE:To improve the corrosion resistance of a forming film by treating an Fe-B-R group sintered magnet body in a short time by a phosphoric acid solution or an organic acid solution, treating the magnet body by an oxalic acid solution, promoting a change into a passive state of a component R easy to be oxidized in the sintered magnet body, particularly, Nd, and executing chemical conversion treatment. CONSTITUTION:There are a dipping method, a spraying method and a steaming method as a treating method by phosphoric acid, formic acid and tartaric acid solutions at a first step in the treatment of a change into a passive state of R, particularly, Nd, in a sintered magnet body, but the dipping method is preferable from the viewpoint of operating efficiency and the stabilization of quality. There are a dipping method, spraying method, steaming method, etc., as a treating method by an oxalic acid solution at a second step, but the dipping method is preferable as the points of operating efficiency and the stabilization of quality. A phosphate film such as zinc phosphate, manganese phosphate, etc. is desirable as a chemical conversion treatment film, but the oxidation resistance of the chemical conversion treatment film is improved remarkably when said pretreatment is executed. |
