Abstract: The present invention provides an excellent non-electrolytic gold plating liquid which produces a gold plating layer firmly adhered to a surface selected from the group consisting of nickel, cobalt, palladium or a metal alloy containing nickel, cobalt or palladium, as well as a method for performing a non-electrolytic gold plating method using the non-electrolytic gold plating liquid. The non-electrolytic gold plating liquid comprises: (1) a water-soluble gold compound; (2) a complexation agent which stabilizes a gold ion in the plating liquid, but does not substantially dissolve nickel, cobalt or palladium; and (3) an anti-gold deposit agent which inhibits excess local etching or corrosion by substitution reaction between the metal surface and gold during the gold plating.

Abstract: An additive for an acidic tinplating bath comprises: an additive ingredient (A) prepared by adding oxypropylene to polyoxyethylene glycol and having an average molecular weight ranging from 3000 to 18000; an additive ingredient (B) prepared by adding oxypropylene to polyoxyethylene glycol and having an average molecular weight ranging from 300 to 1500; and the additive ingredient (A) and the additive ingredient (B) having a weight ratio of the additive ingredient (A) to the additive ingredient (B) being from 97/3 to 40/60.

Abstract: An electrolytic copper plating method using a reducing agent is provided, wherein a catalyzed, electrically nonconductive substrate is dipped in a solution, which contains a copper salt, a copper-reducing agent for the acceleration of copper deposition and a copper-complexing agent and has a pH value of about 6 to 7.5, for electrolysis at a temperature of about 15.degree. C. to 50.degree. C., thereby forming an electrically conductive film of copper on said electrically nonconductive substrate. This method can be used in place of conventional electroless copper plating, dispense with any harmful substance such as formaldehyde, be easily analyzed and controlled, form an electrically conductive film of copper on an electrically nonconductive substrate with improved adhesion thereto, and is effectively applicable to making printed circuit boards in particular.

Abstract: An immersion tin/lead alloy plating bath has a basic composition comprising an organic sulfonic acid, divalent tin and lead salts of the organic sulfonic acid and thiourea and further contains thiocyanic acid or derivative thereof, optionally with hydrated hydrazine. With this plating bath, an alloy deposit, which has a particularly desired Sn/Pb ratio of 60%/40% or so and is improved in terms of adhesion and homogeneity, can be stably obtained on the surface of copper or a copper alloy in a relatively low temperature region within a short span of time.