A Contribution to the Mechanism of Chemical Wear under Boundary Lubrication

Abstract

The mechanism of chemical wear of copper with n-hexadecane containing sulfur was studied. The influence of sulfur concentration, load and temperature on the chemical wear has been investigated. As the mechanism of wear is complex, the simplest possible reaction system was selected.From this work, it is found that there is optimum sulfur concentration at which wear rate and friction coefficient are minimum. From observation of surface and wear particles, it is made clear that before and after the minimum, the mechanism of wear changes. In the less than minimum region, adhesive wear seems to be the main mechanism and in the higher concentration region, the mechanism of wear is mainly flaking of surface films. From the results of the electron diffraction analysis of films and elemental analysis of wear particles, the films are found to be mainly CuS. By EPMA analysis of sulfur concentration in surface films, the minimum is considered to be due to critical film thickness.