Nickel electroplating compositions with cationic polymers and methods of electroplating nickel
Nickel electroplating compositions containing cationic polymers of a reaction product of an imidazole compound and a bisepoxide enable the electroplating of nickel deposits which have uniform bright surfaces over wide current density ranges.
1. A nickel electroplating composition comprising one or more sources of nickel ions, one or more compounds chosen from sodium saccharinate, boric acid and salts of boric acid, optionally, one or more sources of acetate ions, and one or more cationic polymers, wherein the one or more cationic polymers are a reaction product of one or more imidazole compounds having a formula:
wherein R 1 , R 2 and R 3 are independently chosen from H, (C 1 -C 12 )alkyl, aryl, aryl(C 1 -C 6 )alkyl, and amino(C 1 -C 6 )alkyl, and wherein R 1 and R 2 can be taken together with all of their carbon atoms to form a fused six membered ring and one or more bisepoxides having a formula:
wherein Y 1 and Y 2 are independently chosen from H and linear or branched (C 1 -C 4 )alkyl;
A is OR 4 or R 5 , wherein R 4 is ((CR 6 R 7 ) m )O) n , wherein R 6 and R 7 are independently chosen from H, hydroxyl and methyl, and R 5 is (CH 2 ) y , wherein m is a number from 1 to 6, n is a number from 1 to 20 and y is a number from 0 to 6 and when y is 0, A is a covalent chemical bond; and one or more optional additives.
2. The nickel electroplating composition of claim 1 , wherein the one or more cationic polymers are in amounts of at least 0.5 ppm.
3. The nickel electroplating composition of claim 1 , further comprising one or more sources of chloride.
4. The nickel electroplating composition of claim 1 , wherein a pH of the nickel electroplating composition is from 2 to 6.
5. A method of electroplating nickel metal on a substrate comprising:
a) providing the substrate;
b) contacting the substrate with a nickel electroplating composition comprising one or more sources of nickel ions, one or more compounds chosen from sodium saccharinate, boric acid and salts of boric acid, optionally, one or more sources of acetate ions, and one or more cationic polymers, wherein the one or more cationic polymers are a reaction product of one or more imidazole compounds having a formula:
wherein R 1 , R 2 and R 3 are independently chosen from H, (C 1 -C 12 )alkyl, aryl, aryl(C 1 -C 6 )alkyl, and amino(C 1 -C 6 )alkyl, and wherein R 1 and R 2 can be taken together with all of their carbon atoms to form a fused six membered ring and one or more bisepoxides having a formula:
wherein Y 1 and Y 2 are independently chosen from H and linear or branched (C 1 -C 4 )alkyl; A is OR 4 or R 5 , wherein R 4 is ((CR 6 R 7 ) m )O) n , R 6 and R 7 are independently chosen from H, hydroxyl and methyl, and R 5 is (CH 2 ) y , wherein m is a number from 1 to 6, n is a number from 1 to 20 and y is a number from 0 to 6 and when y is 0, A is a chemical bond; and one or more optional additives; and
c) applying an electric current to the nickel electroplating composition and substrate to electroplate a bright and uniform nickel deposit adjacent the substrate.
6. The method of claim 5 , wherein the nickel electroplating composition further comprises one or more sources of chloride.
7. The method of claim 5 , wherein the nickel electroplating composition has a pH of 2 to 6.