PURPOSE: To obtain a gold- or gold alloy-plating composition which enables prevention of burn from being caused at high current density and an improvement in electrodeposition rate of a bright deposition coating film by preparing a plating composition comprising a source of gold ions, optionally a source of alloying metal ions, optionally a complexing agent for the alloying metal ions and a rate-promoting additive compound that is a specific pyridine derivative.
CONSTITUTION: This gold- or gold alloy-plating composition comprises: a source of gold ions; optionally a source of alloying metal (such as nickel or cobalt) ions; optionally a complexing agent for the alloying metal ions; and a rate-promoting additive compound. In the composition, the additive compound is at least one compound represented by the formula 1A or 1B (wherein: each of R1 and R2 is a hydrogen or halogen atom or a formyl, carbamoyl, 1-4C alkyl, amino, phenyl or benzyl group; R3 is a 1-6C alkylene group; and Q is SO2 or CO). Also, the source of gold ions is preferably a gold (I) salt contg. gold in a 2 to 20 g/l concn. and as the alloying metal ions, e.g. nickel, cobalt or iron ions can be used appropriately in a 0.05 to 5 g/l concn. Further, as the complexing agent, citric acid or oxalic acid can appropriately be used in a 0.05 to 10 g/l.
GERARUDASU EE SOMERUSU
HENRIKA EMU EICHI FUAN DERU SH
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