Surface finish and damage in sliding

Abstract

The ability of rubbing surfaces to support load depends on the surface finish. Many types of surface used in engineering have a random structure; their profile may be represented by the waveform of a random signal defined by two parameters σ and β * describing the height distribution and the autocorrelation function respectively. Surfaces covering a range of values of both σ and β * have been prepared and for each surface the ability to withstand damage in conditions of boundary lubrication has been determined. It is shown that the values of σ and β * taken together provide good criteria for assessing this property. For the rougher surfaces a sufficient criterion is the ratio σ/β *. Very smooth surfaces, however, fail readily, and when β * is very small all surfaces fail regardless of the value of σ .