Analysis of interfacial adhesion based on electrical contact resistance measurements

Abstract

An analytical approach for determining the adhesion force and adhesion energy at contact interfaces from electrical contact resistance measurements is presented for isotropic, conductive, and rough surfaces. The method is especially suitable for in situ measurement of adhesion forces in lightly loaded contacts, and because it accounts for the real contact area, it yields more accurate estimates of the adhesion energy than traditional methods based on the apparent contact area of microcantilever beams partially adhered to substrates. The advantage of obtaining adhesion measurements in the case of plastically deformed contacts is demonstrated by the wide range of the electrical contact resistance achieved with this method. The relation between adhesion force and electrical contact resistance is shown to be independent of the surface topography when the asperities deform plastically. For this situation, the present method is especially suitable for adhesion measurements in dynamic systems, where the interfacial topography changes with contact cycles due to irreversible deformation of the asperity microcontacts. Analytical results are presented for the adhesion force and adhesion energy at rough contact interfaces in terms of electrical contact resistance and surface topography parameters. The present analytical approach also provides a means of determining the interfacial surface energy of contacting bodies with known surface energies or the surface energy of two identical contacting surfaces.