Guest particle deformation and powder flow behavior in mechano-fusion: Linking microscopic structure to macroscopic performance

The aim of the presented study lies in the detailed investigation of the influence of certain process parameters (rotational speed, process time), across a wide range of the technically possible process parameter space, of a lab-scale mechano-fusion (MF) device on resulting coating structures. A model particle system with a hard host particle (alumina) and a rather soft and deformable guest particle (polystyrene), both spherical in shape, are utilized to create coated particles via MF. A state of mixing but without coating can be achieved on the lower end (low intensity) of the process parameter combinations and a state of guest particle comminution and complex multi-layer coating structure towards the upper end (high intensity). An extended characterization is performed to understand when the resulting coating structures change from one type to another. On the microscopic scale, the used characterization tools include scanning electron microscopy imaging and determination of Brunauer-Emmett-Teller specific surface area. Additionally, a large focus of this study is the macroscopic investigation of flowability by different approaches and characteristics. All characterizations are performed mainly in the powder state. The influence of non-coated guest particles on the performed analyses is investigated. The correlation of the microscopic structural characteristic with the macroscopic behavior of the coated particles over a wide process parameter space allows the grouping based on specific structure–property relationships and furthers the understanding of mechano-fusion coating. • Mechano-fusion coating structures of alumina (host) and polystyrene (guest) particles. • High process intensities: guest particle deformation and comminution, complex multilayers. • Investigation of structure (SEM, BET) and powder flow (e.g. flow rate). • Correlation established between microscopic structure and macroscopic flow behavior. • Classification of coated particle systems into distinct structure–property groups.