Lateral force–displacement measurements—a new technique for the investigation of mechanical surface properties

Nanoindentation is an established technique for the measurement of hardness and Young's modulus. However, the technique only uses normal forces that are far away from the conditions in most real applications. Usually, lateral forces due to friction act together with normal forces. In order to characterize a protecting coating more comprehensively, scratch tests are used additionally. But these tests normally do not deliver characteristic and comparable material parameters which are independent of the measurement conditions and can serve as input parameters for modeling calculations. This shall be overcome with the measurement of lateral force-displacement curves with the same accuracy as conventional nanoindentation can do in normal direction. We report on experiments with a newly developed device, the so-called lateral force unit. This unit was installed in a UMIS-2000 nanoindenter. We present a characterization of the experimental set-up and point out the new possibilities of measuring mechanical surface properties with such a device. The results of first lateral measurements will be discussed.