| 摘要 |
PROBLEM TO BE SOLVED: To improve the rust preventability in the surface of a constituting member such as the outer ring and the inner ring of a bearing produced of chromium steel having a chromium concentration of 0.5 to 2 wt.% and used for an automobile or the like. SOLUTION: The above bearing constituting member is (1) subjected to anode electrolysis in an acidic treatment liquid of sulfuric acid or the like while imparting supersonic waves thereto, so as to remove a deformed layer or the like on the surface of the bearing constituting member, the bearing constituting member is (2) immersed into a treatment liquid comprising chromic acid, thus chromium is fed to the surface of the member from the treatment liquid, the chromium forms a dense chromium oxide passive film, and the bearing is (3) subjected to cathode electrolysis in a solution comprising acid such as chromic acid and sulfuric acid, and each salt of Mg, Ca and Ba of the above acid, so as to further improve the completeness of the passive film. By performing a series of the treatments, an extremely firm rust preventive film which can suppress rust generation in a corrosion resistance test can be formed on the surface of the bearing constituting member, thus the rust preventability of the bearing constituting member is remarkably improved. COPYRIGHT: (C)2008,JPO&INPIT
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