Alkaline zinc-nickel alloy plating compositions, processes and articles therefrom

Abstract

The present invention relates to an aqueous zinc-nickel electroplating bath, including water; nickel ion; zinc ion; at least one complexing agent; and at least one non-ionogenic, surface active polyoxyalkylene compound, wherein the bath has an alkaline pH. In one embodiment, the zinc ion, the nickel ion and the non-ionogenic surface active polyoxyalkylene compound are present at concentrations sufficient to deposit a zinc-nickel alloy comprising a substantially gamma phase.

1 . An aqueous zinc-nickel electroplating bath, comprising 
 water;    zinc ion;    nickel ion;    at least one complexing agent; and    at least one non-ionogenic, surface active polyoxyalkylene compound, wherein the bath has an alkaline pH.    
     
     
         2 . The bath of  claim 1 , wherein the zinc ion and the nickel ion are present at concentrations sufficient to deposit a zinc-nickel alloy comprising a nickel content from about 3 wt % to about 25 wt % of the alloy.  
     
     
         3 . The bath of  claim 1 , wherein the zinc ion and the nickel ion are present at concentrations sufficient to deposit a zinc-nickel alloy comprising a nickel content from about 8 wt % to about 22 wt % of the alloy.  
     
     
         4 . The bath of  claim 1 , wherein the zinc ion and the nickel ion are present at concentrations sufficient to deposit a zinc-nickel alloy having a substantially gamma crystallographic phase.  
     
     
         5 . The bath of  claim 1 , wherein the at least one non-ionogenic, surface active polyoxyalkylene compound comprises at least one compound having a formula:  
         R 1 —O—[(CH 2 ) n O] x H   (Ia)  or  R 1 —O—[(CHR 2 CH 2 )O] x H   (Ib)  or  R 1 —O—[(CH 2 CHR 2 )O] x H   (Ib)  
       wherein R 1  is an aryl or alkyl group containing up to about 24 carbon atoms, R 2  is an alkyl group containing from 1 to about 4 carbon atoms, n is 2 or 3, and x is an integer between 2 and about 100.  
     
     
         6 . The bath of  claim 1 , wherein the at least one non-ionogenic, surface active polyoxyalkylene compound comprises at least one compound having a formula:  
         R 3 —O—[R 4 —O—] n —X   (IIa)  or  (R 3 —O—[R 4 —O—] n ) a —Y   (IIb)  
       wherein R 3 =a C 1 -C 18  branched or unbranched alkyl, alkylene or alkynyl group, or phenyl-O—[R 5 —O—] m —CH 2 —, in which m=0-100 and R 5  is a C 1 -C 4  branched or unbranched alkylene; R 4 ═C 1 -C 4  branched or unbranched alkylene; X═H, —SO 2 Z, —SO 3 Z, —SO 4 Z, —PO 3 Z 2 , —PO 4 Z 2  (wherein Z independently may be H, an alkali metal ion, or Z 2  may be an alkaline earth metal ion) —NH 2 , —Cl or —Br; Y is an aliphatic polyhydroxy group, an amine group, a polyamine group or a mercaptan group, and a is equal to or less than the number of active hydrogens in OH, —NH, NH 2  or —SH groups on the Y component.  
     
     
         7 . The bath of  claim 6 , wherein the Y group is a glycol having a general formula:  
         HO—[R 6 —O—] n —H   (III)  
       wherein R 6 ═C 1 -C 4  alkylene, or a C 1 -C 4  alkylene substituted with one or more additional hydroxyl groups, or a mixture of such R 6  groups.  
     
     
         8 . The bath of  claim 1 , wherein the at least one non-ionogenic, surface active polyoxyalkylene compound is present in an amount effective to provide grain refinement of a zinc-nickel alloy electroplated with the bath.  
     
     
         9 . The bath of  claim 1 , wherein the complexing agent comprises at least one aliphatic amine.  
     
     
         10 . The bath of  claim 1 , wherein the complexing agent comprises at least one polymer of an aliphatic amine.  
     
     
         11 . The bath of  claim 10 , wherein the polymer is a poly(alkyleneimine).  
     
     
         12 . The bath of  claim 10 , wherein the polymer is a polyethyleneimine.  
     
     
         13 . The bath of  claim 1 , wherein the complexing agent comprises at least one compound represented by the formula  
         R 7 (R 8 )N—R 11 —N(R 9 )R 10    (V)  
       wherein R 7 , R 8 , R 9  and R 10  are each independently alkyl or hydroxyalkyl groups provided that at least one of R 7 —R 10  is a hydroxy alkyl group, and R 11  is a hydrocarbylene group containing up to about 10 carbon atoms.  
     
     
         14 . The bath of  claim 13 , wherein the hydrocarbylene group R 11  is an alkylene group containing from 1 to about 10 carbon atoms.  
     
     
         15 . The bath of  claim 13 , wherein R 7 , R 8 , R 9  and R 10  in Formula (V) are hydroxyalkyl groups.  
     
     
         16 . The bath of  claim 1 , wherein the bath further comprises a reaction product obtained by the process of 
 (a) preparing an intermediate product by reacting formaldehyde with a mixture of    (i.) one or more piperazines having the formula                          wherein R 12  and R 13  are each independently hydrogen or lower alkyl groups, and    (ii.) at least one additional nitrogen-containing compound from the group consisting of ammonia or aliphatic, acyclic compounds containing at least one primary amine group, and    (b) reacting said intermediate product with an epihalohydrin or glycerol halohydrin or mixtures thereof at a temperature within the range of from room temperature to the reflux temperature of the mixture.    
     
     
         17 . The bath of  claim 1 , wherein the bath further comprises one or more auxiliary brightener.  
     
     
         18 . An aqueous alkaline electroplating bath for the electrodeposition of a zinc-nickel alloy coating on a substrate which comprises 
 (A) from about 1 to about 100 g/l of zinc ion;    (B) from about 0.1 to about 50 g/l of nickel ion;    (C) at least one complexing agent at a concentration sufficient to maintain the nickel ion in solution; and    (D) from about 0.1 to about 50 g/l of at least one non-ionogenic, surface active polyoxyalkylene compound.    
     
     
         19 . The bath of  claim 18 , wherein the zinc ion and the nickel ion are present at concentrations sufficient to deposit a zinc-nickel alloy comprising a nickel content from about 3 wt % to about 25 wt % of the alloy.  
     
     
         20 . The bath of  claim 18 , wherein the zinc ion and the nickel ion are present at concentrations sufficient to deposit a zinc-nickel alloy comprising a nickel content from about 8 wt % to about 22 wt % of the alloy.  
     
     
         21 . The bath of  claim 18 , wherein the zinc ion and the nickel ion are present at concentrations sufficient to deposit a zinc-nickel alloy having a substantially gamma crystallographic phase.  
     
     
         22 . The bath of  claim 18 , wherein the at least one non-ionogenic, surface active polyoxyalkylene compound comprises at least one compound having a formula:  
         R 1 —O—[(CH 2 ) n O] x H   (Ia)  or  R 1 —O—](CHR 2 CH 2 )O] x H   (Ib)  or  R 1 —O—](CH 2 CHR 2 )O] x H   (Ic)  
       wherein R 1  is an aryl or alkyl group containing up to about 24 carbon atoms, R 2  is an alkyl group containing from 1 to about 4 carbon atoms, n is 2 or 3, and x is an integer between 2 and about 100.  
     
     
         23 . The bath of  claim 18 , wherein the at least one non-ionogenic, surface active polyoxyalkylene compound comprises at least one compound having a formula:  
         R 3 —O—]R 4 —O—] n —X   (IIa)  or  (R 3 —O—]R 4 —O—] n ) a —Y   (IIb)  
       wherein R 3 =a C 1 -C 18  branched or unbranched alkyl, alkylene or alkynyl group, or phenyl-O—[R 5 —O—] m —CH 2 —, in which m=0-100 and R 5  is a C 1 -C 4  branched or unbranched alkylene; R 4 ═C 1 -C 4  branched or unbranched alkylene; X═H, —SO 2 Z, —SO 3 Z, —SO 4 Z, —PO 3 Z 2 , —PO 4 Z 2  (wherein Z independently may be H, an alkali metal ion, or Z 2  may be an alkaline earth metal ion) —NH 2 , —Cl or —Br; Y is an aliphatic polyhydroxy group, an amine group, a polyamine group or a mercaptan group, and a is equal to or less than the number of active hydrogens in OH, —NH, NH 2  or —SH groups on the Y component.  
     
     
         24 . The bath of  claim 23 , wherein the Y group is a glycol having a general formula:  
         HO—[R 6 —O—] n —H   (III)  
       wherein R 6 ═C 1 -C 4  alkylene, or a C 1 -C 4  alkylene substituted with one or more additional hydroxyl groups, or a mixture of such R 6  groups.  
     
     
         25 . The bath of  claim 18 , wherein the complexing agent comprises at least one aliphatic amine.  
     
     
         26 . The bath of  claim 18 , wherein the complexing agent comprises at least one polymer of an aliphatic amine.  
     
     
         27 . The bath of  claim 26 , wherein the polymer comprises a poly(alkyleneimine).  
     
     
         28 . The bath of  claim 26 , wherein the polymer comprises a polyethyleneimine.  
     
     
         29 . The bath of  claim 18 , wherein the complexing agent comprises at least one compound represented by the formula  
         R 7 (R 8 )N—R 11 —N(R 9 )R 10    (V)  
       wherein R 7 , R 8 , R 9  and R 10  are each independently alkyl or hydroxyalkyl groups provided that at least one of R 7 —R 10  is a hydroxy alkyl group, and R 11  is a hydrocarbylene group containing up to about 10 carbon atoms.  
     
     
         30 . The bath of  claim 29 , wherein the hydrocarbylene group R 11  is an alkylene group containing from 1 to about 10 carbon atoms.  
     
     
         31 . The bath of  claim 29 , wherein R 7 , R 8 , R 9  and R 10  in Formula (V) are hydroxyalkyl groups.  
     
     
         32 . The bath of  claim 18 , wherein the bath further comprises a reaction product obtained by the process of 
 (a) preparing an intermediate product by reacting formaldehyde with a mixture of    (i.) one or more piperazines having the formula                          wherein R 2  and R 13  are each independently hydrogen or lower alkyl groups, and    (ii.) at least one additional nitrogen-containing compound from the group consisting of ammonia or aliphatic, acyclic compounds containing at least one primary amine group, and    (b) reacting said intermediate product with an epihalohydrin or glycerol halohydrin or mixtures thereof at a temperature within the range of from room temperature to the reflux temperature of the mixture.    
     
     
         33 . The bath of  claim 18 , wherein the bath further comprises one or more auxiliary brightener.  
     
     
         34 . An aqueous alkaline electroplating bath for the electrodeposition of a zinc-nickel alloy coating on a substrate which comprises 
 (A) from about 1 to about 100 g/l of zinc ion;    (B) from about 0.1 to about 50 g/l of nickel ion;    (C) at least one complexing agent at a concentration sufficient to maintain the nickel ion in solution; and    (D) from about 0.1 to about 50 g/l of at least one non-ionogenic, surface active polyoxyalkylene compound,    wherein the zinc ion, the nickel ion and the non-ionogenic surface active polyoxyalkylene compound are present at concentrations sufficient to deposit a zinc-nickel alloy comprising a substantially gamma phase.    
     
     
         35 . The bath of  claim 34 , wherein the bath further comprises one or more auxiliary brightener.  
     
     
         36 . A process for electroplating a zinc-nickel alloy on a substrate, comprising electroplating the substrate with the bath of  claim 1 .  
     
     
         37 . A process for electroplating a zinc-nickel alloy on a substrate, comprising electroplating the substrate with the bath of  claim 18 .  
     
     
         38 . A process for electroplating a zinc-nickel alloy on a substrate, comprising electroplating the substrate with the bath of  claim 34 .  
     
     
         39 . An article comprising a substrate electroplated according to the process of  claim 36 .  
     
     
         40 . An article comprising a substrate electroplated according to the process of  claim 37 .  
     
     
         41 . An article comprising a substrate electroplated according to the process of  claim 38.