High speed method for plating palladium and palladium alloys
A high speed method of depositing palladium and palladium alloys is disclosed. The high speed method uses an aqueous, ammonia-based bath which has reduced free ammonia in the bath. The high speed method may be used to deposit palladium and palladium alloy coatings on various substrates such as electrical devices and jewelry.
1. A method comprising:
a) providing a composition consisting of one or more sources of palladium ions, one or more sources of alloying metal ions, wherein the alloying metal ions are selected from the group consisting of nickel ions, cobalt ions, silver ions, zinc ions and iron ions, optionally one or more of alkali metal hydroxides and metal carbonates, optionally one or more buffers selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, acetic acid, boric acid, carbonic acid, citric acid, tetraboric acid, maleic acid, itaconic acid and salts thereof, optionally one or more surfactants, one or more brighteners selected from the group consisting of succinimide, maleimide, quinolones, substituted quinolones, phenanthrolines and substituted phenanthrolines and quaternized derivitives thereof, pyridine carboxylic acids and pyridine carboxylic acid amines, ammonium ions, free ammonia in amounts of 10 g/L to 45 g/L and 80 g/L to 200 g/L of urea, water, and a pH of the composition is from 7 to 8;
b) contacting a substrate with the composition; and
c) generating a current density of at least 10 Amps/dm 2 to deposit palladium alloy on the substrate.
2. The method of claim 1 , wherein the current density ranges from 10 Amps/dm 2 to 100 Amps/dm 2 .