ELECTRODEPOSITION OF SN-AG ALLOY WITH A NON-CYANIDE BATH

A new non-cyanide bath was developed for the electrodeposition of Sn-A g alloys. The bath contains potassium pyrophosphate and iodide as comp lexing agents for Sn and Ag. Alloys containing Ag in the range of 5 to 75 atomic percent could be deposited at room temperature (25+/-2 degr ees C) under the galvanostatic conditions (current density:1 to 10 mAc m(-2)). The Ag content of the electrodeposits decreases with increasin g current density. The electrodeposition potential of Ag in iodide sol ution shifted in the direction of positive potential by the addition o f pyrophosphate. The addition of iodide to the pyrophosphate bath had little effect on the electrodeposition potential of Sn. The morphology was influenced by current density and the deposit composition. Solder ability of electrodeposited Sn-Ah alloy films did not change remarkabl y with composition.