Effect of intermittent fretting on corrosion behavior in electrical contact

The effect of intermittent fretting on fretting-corrosion of tin-plated electrical contact is studied by controlling the iterative fretting on/off motion. Comparison between intermittent fretting and continuous fretting indicates that the former is more effective in reducing the contact resistance increasing. The degradation mechanism of intermittent fretting is compared with that of continuous fretting. When the fretting motion is stopped by intermittent fretting, a thick oxide layer will form on the fretted surface. When fretting motion is resumed, the thick oxide layer will be remarkably delaminated and a wide bare surface will be generated. The ratio of “on/off” period is used as intermittent fretting variable and the increased “fretting on” period accelerates the degradation of the contact resistance. Surface characteristics of fretted area are also analyzed by SEM/EDX and LSM. It is clearly revealed that the “fretting on” period give a rise to electrical contact degradation, at a given period. Therefore, the extent of fretting is an important factor for electrical contact degradation and the “fretting off” period is related to the delay of the degradation.