The effects of design variables and surface films on the contact resistance of copper-copper contact interfaces

Studies are made on the effects of contact normal force, wipe, geometry, and hardness on cylindrical copper-copper contacts. The results show a complex interaction among the variables in determining whether reliable, metallic asperity contact can be established. No straightforward relationship among the variables is established, and no conclusion is reached concerning the effects of any single variable for which exceptions could not be found. Contact wipe and normal force effects are as expected and have the greatest effect on contact resistance. At a normal force of 100 g, the effects of most other variables is extremely large. A new effect of contact wipe is shown. Wipe is beneficial in improving contact resistance. For wipe distances greater than about 0.025 mm, low-contact resistance is generally established. Smaller distances of wipe frequently produce very large increases in contact resistance compared to the zero wipe condition.<
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