Toyoda Gosei Co., Ltd.

Yuji Hotta

Koji Nakatani

Hiroaki Ono

Noritake Isomura

Shiho Fujii

A method for producing a black plated resin part includes the steps of electroplating a resin substrate provided with an underlying plating layer in a trivalent chromium plating bath containing thiocyanic acid, to thereby form, on the underlying plating layer, a black chromium plating layer composed of trivalent chromium and having a thickness of 0.15 &#x3bc;m or more; and immersing the resin substrate provided with the black chromium plating layer in warm water at 30&#xb0; C. or higher for a predetermined time. In the method, the amount of thiocyanic acid contained in the trivalent chromium plating bath, the temperature of the warm water, and the time of immersion of the resin substrate in the warm water are adjusted so that the black chromium plating layer exhibits a b* value of &#x2212;1.7 or less based on the L*a*b* color system.

Method for producing black plated resin part

A black plated resin part includes a resin substrate, an underlying plating layer formed on the resin substrate, and a black chromium plating layer formed of trivalent chromium and having a thickness of 0.15 &#x3bc;m or more. The black chromium plating layer is formed on the underlying plating layer. The chromium in the black chromium plating layer is present in the form of metallic chromium, chromium oxide, and chromium hydroxide, and the black chromium plating layer exhibits a b* value of 3.0 or less based on the L*a*b* color system.

Black plated resin part and method for producing the same

A black plated resin part includes a resin base material, an underlying plating layer including a copper plating layer and a nickel plating layer formed in this order on the resin base material, a black chromium plating layer formed on the nickel plating layer, formed of trivalent chromium, and having a film thickness of not less than 0.15 &#x3bc;m, and a corrosion resistant film formed on the black chromium plating layer, formed of chromic phosphate or molybdenum phosphate, and having a film thickness of not less than 7 nm. A brightness of the black chromium plating layer seen through the corrosion resistant film is expressed by an L* value of not more than 54 based on the L*a*b* color system.

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Kiyosu, Japan

Yuji Hotta