This study investigated the effects of a corrosive atmosphere on whisker growth of a Sn film and a Sn/Cu film that were electrodeposited onto a 42 alloy substrate.
No whiskers were generated on the Sn single layer. However, numerous whiskers with length exceeding 100 μm were generated on the Sn/Cu double layer during 7000 hr in an ambient atmosphere. The whisker generation and growth of both the Sn single layer and the Sn/Cu double layer changed remarkably during 7000 hr under a corrosive atmosphere. This whisker growth behavior that occurred in the corrosive atmosphere was attributed to both the change of the Cu6Sn5 compound based on the mutual diffusion and the state transition of oxide film, depending on corrosion of the Sn film at the surface side.
