Additive manufacturing of polymeric materials has reached a far greater maturity with respect to ceramics, the latter being limited by their high melting temperatures and conventional sintering from powder feedstock. Processing slurry-based feedstock, in which powders are present, poses additional challenges: a high amount of powder is required to promote densification, and results in high viscosity, scattering and sedimentation phenomena in vat photopolymerization processes, as well as clogging problems at the nozzle for extrusion-based processes. Our research activities has therefore been focusing on additive manufacturing of ceramics from liquid feedstock; in particular, we investigated the use of preceramic polymers as well as geopolymers and sol-gel solutions. Despite the many advantages related to their liquid nature, there are also some challenges related to the reactivity of such systems and to the removal of solvents and binders usually present. Here, we present our strategies for producing high quality ceramic components using a variety of liquid feedstock and different additive manufacturing techniques, from direct ink writing and digital light processing to robotic and volumetric additive manufacturing.
Université de Padoue