Abstract: An electroless gold plating bath includes a water-soluble gold compound, a completing agent, an aldehyde compound, and an amine compound represented by R1—NH—C2H4—NH—R2 or (CH2—NH—C2H4—NH—CH2)n—R4 (wherein R1 to R4 represent —OH, —CH3, —CH2OH, —C2H4OH, —CH2N(CH3)2, —CH2NH(CH2OH), CH2NH(C2H4OH), —C2H4NH(CH2OH), —C2H4NH(C2H4OH), —CH2N(CH2OH)2, —CH2N(C2H4OH)2, —C2H4N(CH2OH)2 or —C2H4N(C2H4OH)2, and n is an integer of 1 to 4). The electroless gold plating can be carried out without corrosion of an underlying metal to be plated at a stable deposition rate. Because of the high deposition rate and the immersion and reduction types, thickening of a plated coating is possible in one solution and the color of the coating is not degraded to provide a good appearance while keeping a lemon yellow color inherent to gold.

Abstract: An electroless gold plating bath includes a water-soluble gold compound, a complexing agent, a formaldehyde metabisulfite adduct, and an amine compound represented by R1—NH—C2H4—NH—R2 or (CH2—NH—C2H4—NH—CH2)n—R4 (wherein R1 to R4 represent —OH, —CH3, —CH2OH, —C2H4OH, —CH2N(CH3)2, —CH2NH(CH2OH), —CH2NH(C2H4OH), —C2H4NH(CH2OH), —C2H4NH(C2H4OH), —CH2N(CH2OH)2, —CH2N(C2H4OH)2, —C2H4N(CH2OH)2 or —C2H4N(C2H4OH)2, and n is an integer of 1 to 4). A gold plated coating of a good appearance can be formed without causing a failure in appearance owing to the progress of intergranular corrosion in a nickel surface.

Abstract: A substrate includes a non-conductive portion to be electroless-plated of a substrate, on the surface of which fine metal catalyst particles composed of silver nuclei and palladium nuclei each having an average particle size of 1 nm or less adhere at a high nuclei density of 2000 nuclei/&mgr;m2 or more. The metal catalyst particles are produced by sensitizing the non-conductive portion of the substrate by dipping the substrate in a sensitizing solution containing bivalent tin ions, activating the non-conductive portion of the substrate by dipping the substrate in a first activator containing silver ions, and activating the non-conductive portion of the substrate by dipping the substrate in a second activator containing palladium ions.

Abstract: A substrate includes a non-conductive portion to be electroless-plated of a substrate, on the surface of which fine metal catalyst particles composed of silver nuclei and palladium nuclei each having an average particle size of 1 nm or less adhere at a high nuclei density of 2000 nuclei/&mgr;m2 or more. The metal catalyst particles are produced by sensitizing the non-conductive portion of the substrate by dipping the substrate in a sensitizing solution containing bivalent tin ions, activating the non-conductive portion of the substrate by dipping the substrate in a first activator containing silver ions, and activating the non-conductive portion of the substrate by dipping the substrate in a second activator containing palladium ions.

Abstract: A substrate includes a non-conductive portion to be electroless-plated of a substrate, on the surface of which fine metal catalyst particles composed of silver nuclei and palladium nuclei each having an average particle size of 1 nm or less adhere at a high nuclei density of 2000 nuclei/&mgr;m2 or more. The metal catalyst particles are produced by sensitizing the non-conductive portion of the substrate by dipping the substrate in a sensitizing solution containing bivalent tin ions, activating the non-conductive portion of the substrate by dipping the substrate in a first activator containing silver ions, and activating the non-conductive portion of the substrate by dipping the substrate in a second activator containing palladium ions.