A method for measuring inter-particle Hamaker constants in mineral materials using atomic force microscopy

The rheological properties of cement slurry are primarily influenced by the spatial distribution of particles and their interaction forces.The Hamaker constant plays a crucial role in quantifying these interactions; however, its study has been limited due to technical constraints.Atomic force microscopy (AFM) can measure probe-to-particle surface interaction forces via the microcantilever deformation during the extension and retraction process, but it cannot directly measure particle-to-particle interaction forces.In view of this limitation, this paper introduces an AFM-based test method to quantify the interaction force between particles and a new approach for calculating the Hamaker constant.Using these methods, the particle-to-particle Hamaker constants of cement and fly ash in various environments were investigated.The measured Hamaker constants of different mineral materials ranged from 22.79 to 38.26 10 -20 J in air and from 4.79 to 14.47 10 -20 J in water.The primary factors influencing Hamaker constant were the material properties and the test environment.