Acid zinc and zinc alloy electroplating solution and process

Claim 1

An aqueous acid electroplating solution containing zinc ions in an amount effective to electrodeposit zinc, and optionally cobalt and/or nickel ions in an amount effective to electrodeposit a zinc-cobalt, zinc-nickel, and zinc-cobalt-nickel alloy; boric acid and the bath soluble compatible salts thereof present in an amount of about 2.5 g/l to 25 g/l calculated as boric acid, hydrogen ions present inn an amount to provide a pH on the acid side, and a bath soluble and compatible polyhydroxy additive agent containing at least 3 hydroxyl groups and at least 4 carbon atoms of the structural formula: ##STR8## Wherein: R 1 is --H, --CH 2 --OH, an alkyl group containing 1-4 carbon atoms, a bridging group defined by --R 3 --; R 2 is --H, --OH, --CH 2 OH, a bridging group defined by --R 4 --; --R 3 -- is --CH 2 --, ##STR9## --R 4 -- is --(CH 2 ) c --, or --CH 2 --O--CH 2 --; X and Y are the same or different and are --NR 5 ; --SO 3 H, an alkyl, alkenyl, alkynyl group containing 1 to 4 carbon atoms; an hydroxy alkyl group containing 1-4 carbon atoms, and hydroxy alkenyl and hydroxy alkynyl group containing 3 to 5 carbon atoms; R 5 is --H, an alkyl, alkenyl, alkynyl, or hydroxy alkyl group containing 1-4 carbons; a is an integer ranging from 0-6; b is an integer ranging from 0-6; c is an integer ranging from 1-5; and a+b is an integer from 1-6; as well as the compatible bath soluble Group IA and IIA, zinc and ammonium salts thereof and mixtures thereof.