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 comprising one or more sources of palladium ions, ammonium ions and at least 55 g/L urea;
b) contacting a substrate with the composition; and
c) generating a current density of at least 10 Amps/dm 2 to deposit palladium on the substrate.
2 . The method of claim 1 , wherein the current density ranges from 10 Amps/dm 2 to 100 Amps/dm 2 .
3 . The method of claim 1 , wherein the composition further includes one or more of alkali metal hydroxides and metal carbonates.
4 . The method of claim 1 , wherein the urea is from 80 g/l to 200 g/L.
5 . The method of claim 4 , wherein the urea is from 80 g/L to 150 g/L.
6 . The method of claim 1 , wherein the composition has a free ammonia concentration of less than 50 g/L throughout palladium deposition.
7 . A method comprising:
a) providing a composition comprising one or more sources of palladium ions, one or more sources of alloying metal ions, ammonium ions and at least 55 g/L urea;
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.
8 . The method of claim 7 , wherein the current density ranges from 10 Amps/dm 2 to 100 Amps/dm 2 .
9 . The method of claim 7 , wherein the composition further includes one or more of alkali metal hydroxides and metal carbonates.
10 . The method of claim 7 , wherein the alloying metal ions are nickel ions.
11 . The method of claim 7 , wherein the composition has a free ammonia concentration of less than 50 g/L throughout palladium alloy deposition.