Solutions for fretting corrosion

Application of electronics in systems that are exposed to high vibratory an d shock stresses requires the use of fretting protected electrical connecti ons. Fretting corrosion is caused by a relative motion of mated contact sur faces and results in contact failures, This paper presents a design concept that eliminates the relative motion at the contact point by introducing an additional elastic element. When the male half of a connector assembly moves relative to the female hal f, the contact regions on the male and female contacts will move some dista nce together before they start slipping. The onset of slip is predictable a nd measurable. This paper discusses the formula that determines the limit from where slip starts to occur. Also discussed are the effects of connector and applicatio n parameters such as coefficient of friction, normalforce, spring rate, siz e of displacement, and lubrication. Evidence is presented that confirms the validity of the approach. The AMP Micro-MaTch contact system is used as ex ample (see Fig, 1), Two statements about fretting were verified extra to confirming the validit y of the approach, The first is that a small motion is worse than a large m otion. The second that unplated phosphorbronze behaves better than tinplate d phosphorbronze. Unplated phosphorbronze was also tested with anti-frettin g lubricant and showed very good performance.