Lubrication by Low-Melting-Point Metals at Elevated Temperatures

Measurements of the friction coefficient as a function of temperature, have been carried out using surfaces of stainless steel covered by lead, tin, zinc, cadmium, and Wood's metal applied in powder form. Sonic work has also been done with a few other metal and nonmetal surfaces. In cases where the interaction between the low melting substance and sliding surfaces is high, as revealed by the occurrence of wetting, the friction reaches a peak just below the melting temperature of the substance, and then drops to considerably lower values just above the melting point. The peak below the melting temperature is associated with the formation of large adhering fragments of the low melting substance on the sliding surface. When there is no wetting, the low-melting substance has, either below or above its melting point, essentially no effect on the friction. Contributed by the ASLE Technical Committee on Lubrication Fundamentals and presented at the Annual Meeting of the American Society of Lubrication Engineers held in New York, April, 1963.