A unique testing method for surfaces subjected to combined impact and sliding loads

Several well established tribological testing methods (e.g. pin-on-disk, impact) have been widely used to study treated surfaces or coatings on various substrates. However, many of these existing techniques have limitations, since they mainly focus on a single mode of loading and wear (e.g. only impact or sliding). In this study, a Dynamic Impact and Sliding Test (DIST) for the tribo-mechanical evaluation of surfaces under complex loading conditions is presented, where the surfaces are simultaneously subjected to sliding and impact loading. Such modes exist in many critical applications, from biomedical (e.g. hip/knee implants) to automotive applications (e.g. diesel injectors, engine valves, cam shafts), in cutting tools, general machine parts and systems, etc.

The DIST instrument offers a feasible way for fast, economical and reliable evaluation of complex tribosystems.  Benefits include the time and cost effective evaluation of various surfaces (testing time usually less than a minute) and the better understanding of their peculiarities under such multi-mode loading conditions. Some of the unique characteristics of this new instrument (e.g. combined impact and sliding; wear area in a single small “point”; pre-setting of desired wear depth possible) are discussed and examples of evaluated bulk materials/coatings are presented.