To study the effect of lubricant on tin-coated contact with regard to friction, wear and electric properties, experiments were conducted in a model automotive-contact. Four different lubricants were used: three fluorinated lubricants and one grease, consisting of lithium soap and synthetic oil. A test and evaluation method has previously been developed in order to study the insertion/withdrawal of a typical automotive connector. Using the test method the relation between the electric contact resistance and the insertion force can be evaluated. Moreover, it is assumed that the insertion force is the sum of two parts, a friction shear component and a plowing component. For low contact loads the insertion force can be reduced significantly using an appropriate lubricant, with the contact resistance remaining low and stable. In this paper it is proposed that the reduced insertion force is mainly due to a reduced plowing force. However, for normal loads over 1N, the ratio between insertion force and contact resistance is close to that for unlubricated contacts, Furthermore, the contact resistance can be maintained low when the intermetallic compound is exposed, provided a low viscous lubricant is used.
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