Plating on aluminum alloys

Claim 2

The process for plating aluminum and aluminum alloys which comprises contacting said aluminum with an aqueous activating bath substantially free of active copper ions containing a stannate salt selected from the group consisting of sodium stannate and potassium stannate in a concentration of 10 - 70 grams per liter of tin as stannate; at least one member of the group consisting of sodium and potassium hydroxide in a concentration of from 1.2 grams per liter to 12.0 grams per liter; and 0.01 gram per liter to 25 grams per liter of at least one member of the group consisting of methyl cellulose ethers, polyvinyl alcohols, polyethylene oxide, and polyethylene glycols; maintaining said aluminum and said aqueous bath in contact thereby activating the surface of said aluminum, withdrawing from said aqueous bath said aluminum bearing a film of said aqueous bath, immersing said aluminum bearing said film as cathode in an alkaline bronze bath containing an anode thereby depositing a strike plate on said aluminum, and establishing a negative potential on said aluminum bearing said film with respect to said anode prior to the time said aluminum is immersed in said alkaline bronze bath.

Claim 3

The process for plating aluminum as claimed in claim 1 wherein said aqueous activating bath contains 10 - 70 g/l of tin as stannate salt.

Claim 4

The process for plating aluminum as claimed in claim 1 wherein aluminum is contacted with said stannate bath for 5 - 120 seconds.

Claim 5

The process for plating aluminum as claimed in claim 1 wherein aluminum is contacted with said stannate bath at a temperature of 15° C - 30° C.

Claim 6

The process for plating aluminum as claimed in claim 1 wherein said stannate bath contains free hydroxide in amount of 1.2 to 12.0 g/l.

Claim 7

The process for plating aluminum as claimed in claim 1 wherein said stannate bath contains 0.01 - 25 g/l of addition agent selected from the group consisting of methyl cellulose ethers, polyvinyl alcohols, polyethylene oxide, polyethylene glycol in concentrations up to the limit of the solubility of each.

Claim 8

The process for plating aluminum and aluminum alloys which comprises, seriation, cleaning said aluminum in at least one alkaline cleaner, rinsing said aluminum in water, dipping said aluminum in an acidic solution, sequentially rinsing said aluminum, contacting said aluminum with an aqueous activating bath containing 10 g/l - 70 g/l tin in the form of a stannate salt selected from the group consisting of sodium stannate and potassium stannate, at least one member of the group consisting of sodium hydroxide and potassium hydroxide in a concentration of from 1.2 grams per liter to 12.0 grams per liter; and 0.01 gram per liter to 25 grams per liter of at least one member of the group consisting of methyl cellulose ethers, polyvinyl alcohols, polyethylene oxide and polyethylene glycols, maintaining said aluminum and said aqueous bath in contact for 5 - 120 seconds at 15° C - 30° C thereby activating the surface of said aluminum, withdrawing from said aqueous bath said aluminum bearing a film of said aqueous bath, immersing said aluminum bearing said film as cathode in a bronze bath containing an anode thereby depositing a bronze plate on said aluminum, and establishing a negative potential on said aluminum bearing said film with respect to said anode prior to the time said aluminum is immersed in said bronze bath, rinsing said bronze plated aluminum, in water, and subsequently electroplating said adherent bronze deposit with commercial deposits such as copper, tin, and nickel.

Claim 9

The process for plating aluminum and aluminum alloys which comprises, seriation, cleaning said aluminum in at least one alkaline cleaner, rinsing said aluminum in water, dipping said aluminum in an acidic solution, sequentially rinsing said aluminum, contacting said aluminum with an aqueous activating bath containing 10 g/l - 70 g/l tin in the form of a stannate salt selected from the group consisting of sodium stannate and potassium stannate, at least one member of the group consisting of sodium hydroxide and potassium hydroxide in a concentration of from 1.2 grams per liter to 12.0 grams per liter; and 0.01 gram per liter to 25 grams per liter of at least one member of the group consisting of methyl cellulose ethers, polyvinyl alcohols, polyethylene oxide and polyethylene glycols, maintaining said aluminum and said aqueous bath in contact for 5 - 120 seconds at 15° C - 30° C thereby activating the surface of said aluminum, withdrawing from said aqueous bath said aluminum bearing a film of said aqueous bath, immersing said aluminum bearing said film as cathode in a bronze bath containing an anode thereby depositing a bronze plate on said aluminum, and establishing a negative potential on said aluminum bearing said film with respect to said anode prior to the time said aluminum is immersed in said bronze bath, rinsing said bronze plated aluminum, in water, and subsequently electroplating said adherent bronze deposit with commercial deposits such as copper, tin, and nickel.