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Tin Plating Compositions

IP.com Disclosure Number: IPCOM000090942D
Original Publication Date: 1969-Aug-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Grobin, AW: AUTHOR [+5]

Abstract

Film coatings of tin, electroplated upon a steel or aluminum base, can be made to: 1. Resist destructive allotropic transformations to the powdery condition termed tin pest. 2. Resist formation of the filament phenomenon known as tin whiskers. 3. Resist corrosion and maintain low contact resistance of one ohm or less in hostile corrosive environments. These properties are considered important when coated members are used as constituent elements of electromagnetic shield enclosure assemblies, Faraday cages, of the type used to house data processing systems. 4. Prevent corrosion of the exposed base metal when the coating is cut, nicked, scratched or drilled.

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Tin Plating Compositions

Film coatings of tin, electroplated upon a steel or aluminum base, can be made to: 1. Resist destructive allotropic transformations to the powdery condition termed tin pest. 2. Resist formation of the filament phenomenon known as tin whiskers. 3. Resist corrosion and maintain low contact resistance of one ohm or less in hostile corrosive environments. These properties are considered important when coated members are used as constituent elements of electromagnetic shield enclosure assemblies, Faraday cages, of the type used to house data processing systems. 4. Prevent corrosion of the exposed base metal when the coating is cut, nicked, scratched or drilled.

Coatings with these properties are formed by plating successive layers of nickel and tin over the steel or aluminum base. The nickel coating layer is plated to a thickness of between .0003 and .0006 inches by an electrolytic or electroless technique. Over this the tin layer is electroplated to a thickness of at least .0003 inches. The second layer contains an admixture of from .05 to .6% bismuth.

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