X-ray diffraction method for the investigation of contacts between solid surfaces

Abstract

A coherent X-ray scattering method for investigating the formation of the contact region between two solid surfaces is presented. Diffraction of X-rays from two crossed cylindrical quartz surfaces, coated with Cr and TiO 2, revealed a total contact area of 90 ± 10 μm. In the so-called Hertz model for two surfaces in non-adhesive contact, this value is directly related to the displacement of the surfaces and the applied external force. Values of 40 ± 3 nm for the displacement and 24 ± 3 mN for the force are found. The method is also useful for studying liquids in confinement. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved.