Method of electrodepositing an alloy of tin, cobalt and a third metal and electrolyte therefor

Claim 2

An acidic, aqueous bath for the formation of a bright, tarnish resistant and color stable coating, containing a tin compound providing stannous ions, a cobalt compound providing cobaltous ions and at least one third compound providing ions of a third metal, said third metal being antimony or a metal other than aluminum selected from Periodic Group II B , III A or VI B , said ions being present in amounts sufficient to electrodeposit from said bath at pH of about 1-3, a current density of about 5-45 A/ft. 2 and bath temperature of about 50°-85° C., a ternary alloy consisting essentially of about 40-90 wt. % tin, about 10-50 wt. % cobalt and about 1-28 wt. % at least one of said third metals.

Claim 3

A bath as in claim 1 wherein said third metal is zinc, cadmium, indium, antimony or chromium.

Claim 4

A bath as in claim 1 wherein said third metal is zinc, indium or chromium.

Claim 5

A bath as in claim 1 wherein said tin compound is stannous chloride or stannous fluoborate, said cobalt compound is cobalt chloride, and said third compound is zinc chloride, indium chloride or chromium chloride.

Claim 6

A bath as in claim 4 also containing ammonium bifluoride, hydrochloric acid and ammonium hydroxide, and the concentrations of the ingredients of said bath are: cobalt chloride 20 - 400 g./l. stannous chloride 10 - 100 g./l. ammonium bifluoride 20 - 400 g./l. hydrochloric acid (37%) 40 - 150 ml./l. ammonium hydroxide (28%) 10 - 50 mls./l. zinc chloride 15 - 175 g./l.

Claim 7

A bath as in claim 4 also containing ammonium bifluoride, hydrochloric acid and ammonium hydroxide, and the concentrations of the ingredients of said bath are: cobalt chloride 20 - 400 g./l. stannous chloride 10 - 100 g./l. ammonium bifluoride 20 - 400 g./l. hydrochloric acid (37%) 40 - 150 ml./l. ammonium hydroxide (28%) 10 - 50 mls./l. indium chloride 5 - 35 g./l.

Claim 8

A bath as in claim 4 also containing ammonium bifluoride, hydrochloric acid and ammonium hydroxide, and the concentrations of the ingredients of said bath are: cobalt chloride 20 - 400 g./l. stannous chloride 10 - 100 g./l. ammonium bifluoride 20 - 400 g./l. hydrochloric acid (37%) 40 - 150 ml./l. ammonium hydroxide (28%) 10 - 50 mls./l. chromium chloride 5 - 55 g./l.

Claim 9

A bath as in claim 1 also containing fluoboric acid and ammonium hydroxide, and the concentrations of the ingredients of said bath are: cobalt chloride 100 - 300 g./l. stannous fluoborate (50%) 25 - 75 mls./l. fluoboric acid 75 - 225 g./l. ammonium hydroxide (28%) 25 - 150 mls./l. zinc chloride 10 - 135 g./l.

Claim 10

A bath as in claim 1 also containing fluoboric acid and ammonium hydroxide, and the concentrations of the ingredients of said bath are: cobalt chloride 100 - 300 g./l. stannous fluoborate (50%) 25 - 75 mls./l. fluoboric acid 75 - 225 g./l. ammonium hydroxide (28%) 25 - 150 mls./l. chromium chloride 10 - 75 g./l.

Claim 11

A bath as in claim 1 also containing fluoboric acid and ammonium hydroxide, and the concentrations of the ingredients of said bath are: cobalt chloride 100 - 300 g./l. stannous fluoborate (50%) 25 - 75 mls./l. fluoboric acid 75 - 225 g./l. ammonium hydroxide (28%) 25 - 150 mls./l. indium chloride 5 - 35 g./l.

Claim 12

A process for forming on a substrate a bright, tarnish resistant and color stable coating of an alloy consisting of about 40-90 wt. % tin, about 10-50 wt. % cobalt and about 1 to 28 wt. % of at least one third metal other than aluminum selected from Periodic Groups II B , III A or VI B , which comprises electroplating said alloy from an acidic, aqueous bath at a pH of about 1-3, a current density of about 5-45 A/ft. 2 and a bath temperature of about 50°-85°C, said bath containing about 20-100 g/l of a tin compound providing stannous ions, about 20-400 g/l of a cobalt compound providing cobaltous ions, and about 5-175 g/l of at least one third compound providing ions of said third metal.

Claim 13

A process for forming on a substrate a bright, tarnish resistant and color stable coating of an alloy consisting of about 40-90 wt. % tin, about 10-50 wt. % cobalt and about 1 to 28 wt. % of at least one third metal other than aluminum selected from Periodic Groups II B , III A or VI B , which comprises electroplating said alloy from an acidic, aqueous bath at a pH of about 1-3, a current density of about 5-45 A/ft. 2 and a bath temperature of about 50°-85°C, said bath containing about 20-100 g/l of a tin compound providing stannous ions, about 20-400 g/l of a cobalt compound providing cobaltous ions, and about 5-175 g/l of at least one third compound providing ions of said third metal.

Claim 14

A process as in claim 11 wherein said tin compound is stannous chloride or stannous fluoborate, said cobalt compound is cobalt chloride, and said third compound is zinc chloride, indium chloride or chromium chloride.

Claim 15

A process as in claim 12 wherein the tin compound is stannous fluoborate (50%) and said bath also contains fluoboric acid and ammonium hydroxide in concentrations as follows: fluoboric acid 75 - 225 g./l. ammonium hydroxide (28%) 25 - 150 mls./l.

Claim 16

A process as in claim 11 wherein the tin compound is stannous chloride and said bath also contains ammonium bifluoride, hydrochloric acid and ammonium hydroxide in concentrations as follows: ammonium bifluoride 20-400 g./l. hydrochloric acid (37%) 40-150 ml./l. ammonium hydroxide (28%) 10-50 mls./l.

Claim 17

An acidic, aqueous bath for the formation of a bright, tarnish resistant and color stable coating, containing a tin compound providing stannous ions, a cobalt compound providing cobaltous ions and at least one third compound providing ions of a third metal, said third metal being antimony or a metal other than aluminum selected from Periodic Group II B , III A or VI B , said ions being present in amounts sufficient to electrodeposit from said bath at pH of about 1-3, a current density of about 5-45 A/ft. 2 and a bath temperature of about 50°-85°C, an alloy consisting essentially of about 40-90 wt. % tin, about 10-50 wt. % cobalt, and about 1 to 28 wt. % of at least one said third metal.

Claim 18

An acidic, aqueous bath for the formation of a bright, tarnish resistant and color stable coating, containing a tin compound providing stannous ions, a cobalt compound providing cobaltous ions and at least one third compound providing ions of a third metal, said third metal being antimony or a metal other than aluminum selected from Periodic Group II B , III A or VI B , said ions being present in amounts sufficient to electrodeposit from said bath at pH of about 1-3, a current density of about 5-45 A/ft. 2 and a bath temperature of about 50°-85°C, an alloy consisting essentially of about 40-90 wt. % tin, about 10-50 wt. % cobalt, and about 1 to 28 wt. % of at least one said third metal.