Process for electro-depositing composite nickel layers

Claim 1

In a process for electrodepositing a composite three-layered nickel containing layer on a substrate wherein an inner nickel-containing layer having an average sulfur content of less than about 0.3 percent by weight is electrodeposited on the substrate, an adherent intermediate nickel-containing layer having an average sulfur content from about 0.05 to about 0.5 percent by weight is electrodeposited on said inner layer and an outer adherent nickel-containing layer having an average sulfur content of from about 0.02 to about 0.15 percent by weight is electrodeposited on said intermediate layer and, wherein, said outer layer contains a lower average sulfur content than said intermediate layer and a higher average sulfur content than said inner layer, the improvement which comprises electrodepositing said intermediate layer from an aqueous acidic solution containing nickel ions in an amount sufficient to deposit the desired intermediate nickel-containing layer and a thiazole compound present in an amount sufficient to provide the desired sulfur content in the deposited intermediate nickel-containing layer, said thiazole compound having the structural formula: ##STR3## wherein: X, Y and Z are the same or different and are H, NH 2 , CH 3 , SH, a halogen or NO 2 , as well as the inner salts thereof.