Surface texture changes followed-up in real time during the initial wear transient of dry sliding of steel against several metals using laser light scattering

Previous experimental work has shown the possibility of applying laser light scattering (LLS) methods to study the evolution of surface topography during the initial transient period in a wear experiment on a pin-on disk apparatus. A specific set up of a laser source, pointing towards anywhere on the wear-track of the pin on the disk, and a detector to sense the light scattered from the surface, located off the plane of incidence, providing an LLS signal whose changes are related to the surface damage due to the pass of the pin as it runs over the disk. When applied to monitor the surface changes during the running-in stage, the LLS signal shows a characteristic signature for each material and wear regimen. While typical surface analysis using the pin-on-disk apparatus is done ex situ, after wear took place, our experimental setup is designed to detect the minute changes suffered by the surface of the disk due to mechanical contact with the pin, showing the onset stages of wear during the initial transient, in real time. Ex situ analysis using optical microscopy (OM) and surface roughness measurements provides an insight as to the events leading to the changes in surface texture observed in LLS.