Polyamine brightening agent
A zinc electroplating bath includes zinc ions and a brightening agent. The brightening agent is a polyamine or a mixture of polyamines that include a quaternary ammonium group.
1. A zinc or zinc alloy electroplating bath comprising:
zinc ions and a brightening agent, the brightening agent comprising at least one polyamine that includes the following formula,
the at least one polyamine consisting essentially of a first repeating unit that has the general formula:
and a second repeating unit that has the general formula:
where Δ 1 is O, N, or S; x is an integer from 2 to 6; y is an integer from 1 to 6; z is an integer from 1 to 6; and R 1 , R 2 , R 3 , and R 4 , which is the same or different, is methyl, ethyl, isopropyl, n-propyl, hydroxyethyl, or —CH 2 CH 2 (OCH 2 CH 2 ) m OH; and m is a number between 0-6; wherein the first repeating unit and the second repeating unit are in the same polymer chain.
2. The zinc or zinc alloy electroplating bath of claim 1 , the first repeating unit having the following formula:
3. The zinc or zinc alloy electroplating bath of claim 1 , the polyamine having the following general formula:
where v is an integer greater than 1.