Wear of Gold Plate: Effect of Surface Films and Polymer Codeposits

Gold platings obtained from some solutions contain codeposited organic compounds. It is of interest to know whether such materials affect the friction and wear of electrodeposits which are used on the contacts of slip rings, connectors, and other devices. Studies were made of the polymer contents of golds and, with the scanning electron microscope, their location in the deposits, and the results correlated with sliding properties. Polymers were found in discrete pockets in the deposits, with no detectable organics on their surfaces. There is no evidence that polymers significantly reduce friction and wear by serving as lubricants. The sliding properties of gold electrodeposits are, however, closely related to their hardness, and metallic additives in the gold, such as cobalt or nickel from about 0.1 to 1 percent, are recommended hardener elements. Adventitious organic contaminants from the air can accumulate on surfaces and may provide effective lubrication for lightly loaded sliding gold contacts.