Cluster Formation of Clay-like Colloids in Shear Flow

In Al2O3 suspensions, depending on the experimental conditions very different microstructures can be found, comprising fluid like suspensions, a repulsive structure, and a clustered microstructure. For technical processing in ceramics, the knowledge of the microstructure is of big importance, since it essentially determines the stability of a workpiece to be produced. To enlighten this topic, we investigate these suspensions by means of a coupled Stochastic Rotation Dynamics (SRD) and Molecular Dynamics (MD) simulation. In the present paper we utilize the structure factor and the pair correlation function as analysis tools to observe cluster formation. The first one observes on the length scale of the system size, whereas the latter focuses on short discances to the nearest neighbours. Both observation tools show good agreement among each other. The repulsive microstructure can be identified by means of the mean squared displacement of the particles. The results from different evaluation tools are summarized in a stability diagram. PACS. 82.70.-y Disperse systems; complex fluids – 47.11.+j Computational methods in fluid dynamics – 02.70.Ns Molecular Dynamics and particle methods