Performance of the gold-tin connector interface in a flight environment

Field and laboratory studies were conducted over a 2-year period to confirm a suspected failure mechanism in a flight critical electrical connector. The connector involved the combination of gold-plated sockets mated to solder-plated pins in a 6 pin, circular military connector. The suspected failure mechanism was fretting corrosion. A second objective was to evaluate the effects of a MIL-L-87177A lubricant on this combination. This lubricant was being considered as a potential field "fix" on systems already deployed (and potentially in a degraded state) in the field. Flight tests confirmed the rapid degradation of an unlubricated population of samples. This occurred in all environments studied including two that were considered noncorrosive. The mechanism was confirmed to be fretting corrosion. Parallel flight tests on lubricated hardware demonstrated the ability of a lubricant to delay the onset of fretting corrosion for at least 1 but less than 2 years. Laboratory tests confirmed that vibration was the major stress, which was responsible for the degradation of this system. Lubrication effectiveness was confirmed to delay but not totally prevent fretting corrosion. Finally, it was demonstrated that lubrication was effective in restoring a degraded system.