Accelerated storage degradation testing and failure mechanisms of aerospace electromagnetic relay

It is difficult to obtain the failure data of high-reliability and long-lifetime aerospace electromagnetic relay (EMR), even if based on the traditional accelerated storage life testing method. Based on the reliability test technique, the scheme of accelerated degradation testing for aerospace EMR was designed. The test system of aerospace electromagnetic relay storage parameters under temperature-accelerated stress was designed and developed. The most past research on storage reliability of relay only focuses on the measurement of contact resistance. The relay time parameters (pick-up time, opening time, overtravel time, rebound duration time, etc.) which reflect main performance function were not monitored. So, in this study the relay time parameters and relay contact resistance were detected simultaneously. According to the analysis on experiment results of contact resistance, relay time parameters, the degradation phenomena of aerospace EMR in long-term storage are investigated, which provides the bases for determining degradation sensitive parameters. Finally, based on the structure and function of aerospace EMR, the storage failure mechanism is investigated by conductive properties themselves. The microscopic morphology and changes in chemical elements for relay contact surface was analyzed by SEM and EDX regularly, which provide references for the relay storage failure mechanism.