Title: Electroless tin and tin-lead alloy plating baths

Abstract: Salt compositions and baths thereof useful in, and methods for, immersion plating of tin and tin-lead alloys which give greatly increased deposition rates and thicker coatings of better quality accomplished by incorporating into immersion plating tin bath compositions soluble plumbous salts in the amount of from 0.5 grams per liter calculated on the basis of elemental lead to the maximum amount soluble in the bath and a sulphur-containing complexing agent for the tin and lead such as thiourea or a thiourea-type derivative. Preferably the salt elements are stannous chloride, lead chloride, sodium hypophosphite (as a solubility enhancer) and with hydrochloric acid used as a agent for adjusting the pH in the resulting bath from 0.5 to 1.0.

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Inventors: Davis, Thomas Francis (Harrisburg, PA, US)

Application Number: 574979
Filing Date: 1975-05-06
Publication_date: 1978-06-06
Assignee: AMP Incorporated (Harrisburg, PA)
Primary Class(es): 106/1.22 427/437
Other Classes:
US Patent Ref:

2369620	Feb, 1945	Sullivan et al.	427/436.
3050410	Aug, 1962	Greene	106/1.
3303029	Feb, 1967	Shipley	106/1.

Other Refs:
Primary Examiner: Hayes, Lorenzo B.
Assistant Examiner:
Attorney: Kita; Gerald K.