| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive chromium plating film formed on the surface of the parts of an internal combustion engine and excellent in wear resistance and fatigue strength. SOLUTION: This chromium plating film formed on the surface of the base material to be plated is composed of laminated chromium plating layers 1. In each chromium plating layer 1, the granular columnar dimensions in the chromium plating structure are 0.05 to 3.0μm, the thickness is 1 to 40μm, and the granular columnar dimensions take uniform value, or value continuously changing toward the direction made far from the base material to be plated or irregular value. The thickness of the undercoat layer is 2 to 80μm. In the hard plating stage in the chromium plating film forming process, the electric current applied on the base material to be plated is changed, and the prescribed granular columnar dimensions can be obtd.
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