Intermittency phenomena in electrical connectors

Abstract

Abstract-Fretting is known to be a major cause of contact deterioration and failure, particularly in tin-plated contacts. During fretting the contact resistance generally increases slowly with time. Superimposed on this slow increase in contact resistance are rapid changes in contact resistance within fractions of a second, called intermittences or short duration discontinuities. Although intermittences have been reported by several authors, they are frequently overlooked in traditional fretting experiments and not much is known about their origin. The present study aims at filling this gap.A test apparatus has been built to measure the contact voltage-drop profile during an intermittence and fretting experiments on tin-plated copper contacts have been carried out. The results lead to a set of requirements for a model to explain intermittency phenomena.

The Relationship Between Surface Wear and Contact Resistance During the Fretting of <emphasis emphasistype="italic">In-Vivo</emphasis> Electrical Contacts

“…With limited samples and with uncertainty associated with the volumetric data, the trend in Fig. 13 is presented as an indication of the expected increase in wear with contact force, in line with the model expressed in (2). There are a number of potential error sources associated with the volumetric wear calculation; the most significant is the relationship to the surface volumes for the unworn surface over the same area as that used for the calculation in Table I.…”

“…2008.2001162 connector systems where the conduction path across the electrical contact interface is disrupted for a short duration [2]- [5]. These events can cause difficulties with electronic systems and result in system failure.…”

“…A high frequency intermittency testing station has been used for the study [1], [2], [4]. It consists of a motion system that moves one contact member (the coupon) in the horizontal plane to create the fretting motion while maintaining the contact force of the second contact (rider).…”

Corrosion of RoHS-Compliant Surface Finishes in Corrosive Mixed Flowing Gas Environments

“…17,22 The mechanism by which the corrosion occurs in porous gold finishes is well understood and has been previously documented. 20,[29][30][31][32] According to this mechanism, a defect within the gold layer in contact with the nickel layer underneath becomes anodic with respect to the surrounding cathodic gold layer. Under MFG conditions, an invisibly thin but finite water layer forms on the gold surface, which combines with corrosive gas that dissociates to form a concentrated surface solution providing a low-conductivity electrolytic path between the gold and nickel through the surface defect.…”

Fluctuation of Contact Voltage During Fretting Phases

“…This movement is controlled and measured by a displacement sensor (using laser with 0.1µm of resolution) focused. These parameters simulate real conditions of use of a contact in the automotive connectors [2][3][4][5]. Figure 3 gives the change of contact voltage and contact temperature measured near the contact interface between the two sample parts versus the number of vibration cycles.…”