Sol-gel inks for Additive Manufacturing of ceramic-based materials

Additive manufacturing processes have represented a milestone breakthrough over a broad range of technologies, enabling the fabrication of three-dimensional structures with utterly unique architectures over different length scales. Significant efforts have been devoted thus far to developing feedstock formulations for the fabrication of components with previously unattainable degrees of complexity over a wide range of materials, including ceramics, polymers and metals. Significant possibilities exist to further extend this fabrication concept to several industrial sectors, thus contributing to enrich the panel of materials of scientific and technological interest. Here we explore the coupling of AM technologies with various sol-gel-based methodologies to create ceramic components with different nanoarchitectures. Glass has traditionally earned a privileged position in different applications, spanning from the fabrication of artistic endeavours, packaging and windows in our homes, to more technological fields and scientific research. Modern manufacturing techniques have delved deeply into developing fabrication methods for creating complex 3D printed glass components; however, further refinement is imperative to enhance the final optical quality. We report a novel approach to prepare sol-gel-based photocurable feedstocks compatible with UV-assisted direct ink writing and DLP techniques, demonstrating high chemical flexibility and great potential in tuning the optical properties. Complex-structured parts were printed and successfully converted into fully dense, transparent and crack-free silica-zirconia, silica-titania and silica-zirconia-titania glasses. Furthermore, we develop a feasible protocol for the fabrication of hierarchical porous titanium carbide/carbon nanocomposite via DLP, designing a bottom-up approach to achieve a fine control over the organisation and positioning of the structural units, with particular focus on nanoscale porosity to adhere to the standards required for nuclear applications. By easily playing with the choice of the network-forming motifs, the synthetic strategy allows for a large variety of modifications and is extended to the fabrication of other systems, including lanthanum dicarbide/carbon and uranium dicarbide/carbon materials. Therefore, the novel approaches herein proposed hold great promise in broadening the field of ceramic-AM, providing reliable synthetic routes that allow to overcome the several limitations of conventional manufacturing processes. Moreover, the extraordinary variability of the chemical pathways paves the way for the development of advanced custom-made materials.