The Role of Aluminum Segregation in the Wear of Aluminum/Bronze-Steel Interfaces Under Conditions of Boundary Lubrication

An interest in the wear of steel nonsteel systems, currently in use in aircraft fuel systems, has led to a study of aluminum bronze sliding on KE961 steel in the presence of kerosene with, and without, the addition of a commercial boundary lubricant. Experiments were conducted to determine wear rates with change of load together with an extensive investigation of the contacting surfaces using physical techniques such as EPMA, SEM and Auger spectroscopy.

It was found that the additive had an initial pro-wear effect on the bronze followed by a sharp reduction in wear. The results of the measurements, and of the surface analysis, indicate that the mechanism responsible for this wear is due to preferential segregation of the aluminum to the surface. In the absence of the additive, aluminum is transferred to the steel and forms a solid solution which can cause seizure to occur.