Abstract: A pre-treatment method for plating wherein lead or the like dissolved in an etching liquid is not electro-deposited (re-adhesion) on a lead-contained copper alloy to be plated even without adding a chelating agent forming an insoluble inert combined substance. The lead-contained copper alloy to be plated is dipped in an alkaline etching liquid without adding a chelating agent which would form an insoluble inert combined substance. In this state, electrolysis where the lead-contained copper alloy functions as one of a positive electrode and a negative electrode, and electrolysis where the lead-contained copper alloy functions as the other of the positive electrode and the negative electrode are performed alternately (PR electrolysis).

Abstract: According to the present invention, there is provided a method for forming a mark having superior conspicuity, wherein plural plating layers each having a different hue are formed on a base, a portion of the upper plating layer is removed by laser marking so as to reveal the color of the lower plating layer, and thereby the color difference between a mark and the upper plating layer is made clear. Further, after the upper plating layer is removed by laser marking, another plating layer may be applied to a mark portion to make the mark conspicuous. Furthermore, a concave portion or concavo-convex portions may be provided on the surface of the plating layers, and the concave portion or concavo-convex portions may be colored with ink or paint. With these methods, it is possible to easily form a colored mark having superior conspicuity, corrosion resistance, adhesion, abrasion resistance and to produce a product bearing such a mark.

Abstract: According to the present invention, there is provided a method for forming a mark having superior conspicuity, wherein plural plating layers each having a different hue are formed on a base, a portion of the upper plating layer is removed by laser marking so as to reveal the color of the lower plating layer, and thereby the color difference between a mark and the upper plating layer is made clear. Further, after the upper plating layer is removed by laser marking, another plating layer may be applied to a mark portion to make the mark conspicuous. Furthermore, a concave portion or concavo-convex portions may be provided on the surface of the plating layers, and the concave portion or concavo-convex portions may be colored with ink or paint. With these methods, it is possible to easily form a colored mark having superior conspicuity, corrosion resistance, adhesion, abrasion resistance and to produce a product bearing such a mark.