Our work describes an optimised procedure for granulating nanometric and fine micrometric particles by spray-drying to achieve ready-to-print ?-AlO powders. The study started by identifying raw materials suited for the process through complete characterisation of particles shape, size, and surface properties. Then, dispersion in diluted and concentrated water-based suspensions was achieved thanks to polyethyleneimine and the effect of gradual dispersant addition was assessed by determining ? potential and aggregates size variation. Suspensions rheology was studied and modelled through Krieger-Dougherty equation to identify the maximum solid loading allowing sufficient feeding through the spray-dryer nozzle. Finally, optimisation of the granulation conditions was performed. The procedure has allowed to achieve size distributions with D < 50 ?m and Hausner ratio <1.3 ensuring sufficient flowability. The granulated powders were printed and the porosity evolution of the samples after sintering was studied by mercury intrusion porosimetry and SEM analysis.
Tailoring ?-alumina powder morphology through spray drying for cold consolidation by binder jetting
Mercadelli E;Galassi C;
2022
Abstract
Our work describes an optimised procedure for granulating nanometric and fine micrometric particles by spray-drying to achieve ready-to-print ?-AlO powders. The study started by identifying raw materials suited for the process through complete characterisation of particles shape, size, and surface properties. Then, dispersion in diluted and concentrated water-based suspensions was achieved thanks to polyethyleneimine and the effect of gradual dispersant addition was assessed by determining ? potential and aggregates size variation. Suspensions rheology was studied and modelled through Krieger-Dougherty equation to identify the maximum solid loading allowing sufficient feeding through the spray-dryer nozzle. Finally, optimisation of the granulation conditions was performed. The procedure has allowed to achieve size distributions with D < 50 ?m and Hausner ratio <1.3 ensuring sufficient flowability. The granulated powders were printed and the porosity evolution of the samples after sintering was studied by mercury intrusion porosimetry and SEM analysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
