Plastic products have high productivity for their high corrosion resistance and large-quantity injection molding. When they are coated with metal decoration, they have higher durability and shock-resistance. It means they have longer life time.
Extrinsic decoration methods include evaporation, plating and electrophoresis, of which plating is most widely used. The most suitable plastic for plating is acrylonitrile-butadiene-styrene (ABS).
Decorative nickel plating of acrylonitrile-butadiene-styrene (ABS) plastics has depended on pretreatment of precious metals including Cr and Pd, but it is subject to restriction due to both environmental pollution by chromium oxides and increasing prices of precious metals.
Kim Kyong Chol, a researcher at the Faculty of Chemical Engineering, has found a reasonable method of etching and forming a conducting layer in the pretreatment process of plastic products, and investigated the influences of some factors.
Permanganate was used for etching and the conducting layer was formed by complexing agent of tartaric acid and lactic acid. First, he investigated the etching characteristics in terms of amounts of potassium permanganate, phosphoric acid and sulfuric acid, and then, he assessed the characteristics of the conducting layer with respect to the amounts of metal ion, mixed ligand and temperature.
The scanning electron microscope (SEM) images, X-ray diffraction (XRD) patterns and electric resistances confirmed that the current etching is environmentally friendly and the electric resistance of formed Cu2S is below 50Ω/cm2.
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