| 摘要 |
PROBLEM TO BE SOLVED: To improve the releasability, wear resistance and corrosion resistance of a die by applying strike nickel plating to the surface of a die of a sealing material and thereafter forming nickel-phosphorus-tungsten coating film thereon by electroless plating. SOLUTION: On the surface of a sealing material forming die in contact with a melted sealing material, a nickel plating layer is formed by a strike plating method. On the surface, nickel-phosphorus-tungsten film is formed by an electroless plating method, or, after the formation of strike nickel plating, nickel-phosphorus film is formed by electroless plating, and furthermore, nickel- phosphorus-tungsten film is formed thereon by electroless plating. By the application of the strike nickel plating, the subsequently formed electroless plating layer and the die base are firmly and closely adhered. The thickness of the nickel coating shall be regulated to an extremely thin one, and ordinarily, it is regulated to about 0.1 to 2μm. The nickel-phosphorus film relaxes and evades stress caused by the hardness of the nickel-phosphorus-tungsten film formed thereon.
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