Abstract
HOT-DIP tin plating, which is a kind of the melting plating processes, has been the mainstream of tin plating using as connectors of electric devices, and has some advantages such as low environmental load and no short circuit caused by formation of whisker. As plated, the intermetallic layer is caused by diffusion between melted tin liquid and phosphorous bronze substrate on HOT-DIP tin plating. However, it has been reported that another intermetallic layer, which has high hardness and brittle behavior, is composed in elevated temperature during actual application. In this study, some observations and analysis were carried out on the HOT-DIP tin plating specimens subjected to different heat treatments (temperature and environment) to discuss the influences of both temperature and environment on formation of another intermetallic layer. Furthermore, ultra-micro indentation testing on them surface by various indentation loads were conducted to detect the formation and the growth of another intermetallic layer easily.
