Pretreatment process of tin lead plating
AssigneeShipley Company, L.L.C.
InventorRichard A. Iantosca
Life of this patent
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Abstract
A process for plating a tin-lead alloy on a substrate by displacement plating from an immersion plating solution containing dissolved tin and lead. The process includes the steps of pretreatment of a substrate by contact with a solution containing a pH adjustor for said immersion deposition solution followed by contact of the substrate with said immersion plating solution for a time sufficient to deposit an alloy of tin and lead.
Claims22
A process for plating a tin-lead alloy on cupreous substrates by displacement plating from an immersion plating solution having a pH varying between 0.0 and 1.5 containing dissolved tin and lead salts, said process comprising the steps of pretreatment of the substrates by contact of the substrates with a pretreatment solution containing an acid pH adjustor followed by contact of the substrates with said immersion plating solution for a time sufficient to deposit an alloy of tin and lead by displacement of copper by tin and lead, said pretreatment solution containing said acid pH adjustor in a concentration sufficient to maintain the pH of the immersion plating solution essentially constant by drag in of pretreatment solution on substrates as they pass from the pretreatment solution to the immersion plating solution in said steps of contact of the substrates with said pretreatment solution and said immersion plating solution.
A process for continuously plating cupreous substrates with a tin-lead alloy deposit of uniform concentration and sturcture from substrate to substrate by displacement plating from an immersion plating solution having a pH varying between 0.0 and 1.5 containing dissolved stannous and plumbous ions and members selected from the group of lead promoters, complexing agents for tin and lead, exaltants and mixtures thereof, said process comprising the steps of pretreatment of the substrates by contact of the same with a pertreatment solution containing an acid pH adjustor followed by contact of the substrates with said immersion plating solution for a time sufficient to deposit an alloy of tin and lead by displacement of copper by tin and lead, said pretreatment solution containing said acid pH adjuster in an amount sufficient to maintain the pH of the immersion plating solution essentially constant by said steps of contact of the substrates with said pretreatment solution and said immersion plating solution by drag in of pretreatment solution on said substrates in said immersion plating solution.
Dependencies are inferred from the claim text.