Lubrication Quantity: Observations of the Effects on Gold Sliding Contact Wear Character and in situ Contamination Formation

It has been observed that for certain slip-ring assemblies the wear character is altered by varying lubricant quantity. These observations were made on gold alloy sliding contacts tested under closely controlled laboratory conditions and on similar contacts taken from field installations. For thin-film boundary lubrication, the wear process follows the adhesive and abrasive modes set forth by Antler. However, for the flooded boundary lubrication, the wear process appears to stay in the adhesive mode as long as the flooded condition exists. In both the thin-film and flooded cases debris average particle size and coefficient of friction are in qualitative agreement with the expressions set forth by Rabinowicz in his surface energy of adhesion theory. The observations regarding wear character were the same for sliding in clean or multichemical environments. However, when operation in a multichemical environment is required, it is shown that, because of in situ contaminant formation in the contact zone of thin-film lubricated contacts, flooded lubrication may be more desirable.