Effects of wipe on contact resistance of aged surfaces

Probe measurements were made on corroded test coupons to show the effects wipe has on contact resistance. Data are provided for two types of films; oxidized copper and corrosion on porous gold due to flowing mixed gas tests (FMG). The results in both cases show contact resistance is reduced by nearly two orders of magnitude for 0.25-mm wipe. In addition, a Monte Carlo analysis was conducted using a modified version of a previously developed model of degradation. This included adding film resistivity as a random variable for asperities that were previously considered nonconductive, and incorporating wipe in the model by considering shear forces to produce additional asperity deformation. The Monte Carlo results agree reasonably well with observation as differences can be explained within the framework of the model. It is believed improvements can be made on the predictions of the model if the mechanism of film removal and adhesion, and the variation of film resistivity are better understood.<
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