Coupling effect of adipic acid and Cl- on anodic dissolution of SAC305 solder alloy for printed circuit boards

The coupling effect of adipic acid and Cl - on the corrosion of SAC305 solder alloy is systematically investigated. Electrochemical measurements prove that Cl - could completely destroy the protectiveness of adipic acid and accelerate metal corrosion. Morphology characterizations and XPS analyses verify that the amount of adsorbed adipic acid on the metal surface is largely reduced due to competitive adsorption of Cl - . TEM and Mott-Schottky tests further reveal that the defect density of the oxide film developed in Cl - environment is three times higher than that in adipic acid, which is responsible for the faster anodic dissolution.