| 摘要 |
PROBLEM TO BE SOLVED: To smoothen the inner circumferential face of a cylinder block, simultaneously to deposit a Zn film, to reduce the number of treating steps, furthermore to deposit a plating film of an Ni-Cu alloy having corrosion resistance to sulfuric acid components on the inner circumferential face of the cylinder block and thereby to improve the durability of the cylinder block. SOLUTION: A liquid 21 containing Zn(zinc) ions and glass beads 22 are mixed, this mixture 23 is injected on the inner circumferential face 12 of a cylinder block 10 via an injecting means 25 to smoothen the inner circumferential face 12 and also to deposit a Zn film 13, and, after that, the inner circumferential face of the cylinder block 10 is deposited with a plating film 14 of an Ni(nickel)-Cu(copper) alloy via the Zn film 13.
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