Influence of hematite film and loading pattern on the mechanics of particle and proppant-shale rock systems

We examine the tribological behavior of particle–particle and particle-shale rock systems in the presence of hematite film (iron oxide nanoparticles) simulating iron oxide development on the surfaces of geological materials. By applying different boundary conditions and loading patterns to the samples, we examined the interfaces in both full and partial slip as well as under the influence of a sudden change of the normal load during shearing. We observed that the influence of hematite film (iron oxide nanoparticles) on the normal contact stiffness may alter depending on whether shear stresses are induced or not. In steady-state sliding, the data show that the hematite film (iron oxide nanoparticles) has a greater influence in grain-rock than that in grain-grain systems; however, both the normal contact and shearing behavior depend, primarily, not on the presence of the iron oxide nanoparticles alone, but the combination of surface film and loading pattern. In part of our grain-scale data, we could provide inferences on previous macroscopic test results as we observed similar patterns of behavior at different scales. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.