How to measure the real contact area? A simple marker and relocation foot-printing approach

A marker layer (Au80Pd20) combined with four different techniques was used in order to estimate the real contact area between static steel steel contact pairing (substrate: AISI304 and ball: AISI 52100). The experiments were done with polished references (substrate and ball) and with substrates having a laser patterned line-like surface topography using two loads (1 and 5 N) and two pattern periodicities (9 and 15 gm). Irrespective of the normal load, all techniques led to the same results within the standard deviation for the polished surfaces. For the laser-patterns, only the combination of foot-printing, scanning electron microscopy and image segmentation is capable to provide meaningful results, since the other techniques significantly overestimate the real contact area. (C) 2016 Elsevier Ltd. All rights reserved.