| 摘要 |
PURPOSE:To accurately transfer the ruggedness on a mother to the surface of a forming die and to improve he surface hardness and corrosion resistance of the titled forming die by plating a hard metal on the surface of the mother in two layers, then coating a metal on the hard metal-plated surface by electrocasting, and releasing the mother from the hard metal-plated surface. CONSTITUTION:A passive layer is formed from the surface of the mother 1 toward the inside in several tens Angstrom depth in an aq. 10% NaOH soln. by a backward current treatment at 50 deg.C and 5V bath voltage. Then an Ni-P hard metal is firstly plated on the passive layer 2 of the mother 1 to form a hard metal-plated film 3. The Ni-P hard metal is secondly plated on the hard metal- plated film 3 under specified conditions to form a hard metal plating 4. Successively, nickel sulfamate plating is carried out at 50 deg.C, 5Angstrom /dm<2> cathode current density, and 4.2pH by using a plating bath having a specified composition to coat the metallic body 5 of the nickel-electrocast layer in specified thickness. After the formation of the metallic body 5 of the nickel-electrocast layer is finished, the hard metal-plated film 3 is released from the mother 1 (including the passive layer 2) to obtain a stamper 6.
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