Fretting motion in static contacs of mated metals can lead to a remarkable increase of their contact resistance. When such fretted contacts are in the state of being totally cut off from any electric source, a millivolt-order contact voltage is often induced in them. An outline of such voltage generation was reported in the former letter. In this phenomenon, the most interesting fact is that the emerging voltage has a particular polarity, when dissimilar metals are meted as contacts. This letter deals with continued experimental studies concerning such contacts of mated dissimilar metals and physical discussions on the emerging voltage with a particular polarity.

Fretting means an oscillatory sliding micromotion. It is well known that contact resistance of static contacts, such as electronic connector, increases remarkably, when such contacts are subjected to fretting. When such fretted contacts are in the state of being totally cut off from any electric source, a millivolt order contact voltage is often induced in them. This paper deals with some experimental stuides and physical discussions on this voltage-emerging phenomenon.