Using tin-plated terminals generally used for vehicle connectors, we studied the variation in thickness of the oxide film on the terminal surface, progress of copper diffusion to the tin-plated layer, and terminal stress remaining rate against the ambient conditions of temperature, humidity, and oxygen concentration. As well, we collected terminals from aged vehicles for actual field data, and tested them in the same way.
We analyzed the obtained data using the regression analysis technique and obtained an expression for the relationship between the environmental factors and the transition of the terminal state as time elapses. This paper describes the accelerated test method that produces the same results as actual products used for ten years, by making calculations with the said expression.