Fractal characteristics of dry sliding surfaces based on 3-D measurements

3-D surface morphology measurements of compact graphite irons were used to analyze the fractal characteristics of the surfaces to relate the dry sliding surface morphology to the fractal dimension. The measurements show that the fractal dimensions (D_f) of the sliding surfaces vary from 1 to 2 and are closely related to the surface morphologies. Increasing depths of grooves or pits increases the D_f values. At the same time, increasing densities of the grooves also causes the D_f values to increase. The data can be used to discuss relationship between D_f and the friction coefficient as well as the wear rate.