3D Printing of Ceramics with Controllable Green-Body Configuration Assisted by the Polyvinyl Alcohol-Based Physical Gels

Additive manufacturing of ceramics has received intense attention. In particular, 3D-printed ceramics with customized shapes are highly desirable in the chemical industry, aerospace, and biomedical engineering. Nevertheless, developing a simple and cost-effective process that shapes dense ceramics to complex geometries remains challenging because of the high hardness and low ductility of ceramic materials. Extrusion-based printing, such as direct ink writing (DIW), often requires supporting materials that pose additional difficulties during printing. Herein, a simple approach is developed to produce stretchable ceramic green bodies of zirconia and alumina for DIW. The ink is composed of polyvinyl alcohol (PVA) and an aqueous suspension of ceramic powders. Besides the colloidal network formed by the ceramic particles, PVA plays an important role in tuning the printability of the aqueous ink. Through a freeze-thaw process, PVA crystallizes to form physical networks. This strategy provides highly stretchable hydrogel green bodies that can be reprogrammed to complex geometries difficult for common DIW printing. The subsequent drying, debinding, and sintering processes produce ceramics with dense structures and fine mechanical properties. In short, this work demonstrates an efficient method for the DIW of ceramic parts that can be reprogrammed to complex geometries. This work demonstrates a simple strategy for the additive manufacturing of geometrically complex ceramic materials by direct ink writing. Polyvinyl alcohol in aqueous ink of ceramic suspension forms a physical network by a simple freeze-thaw process and leads to hydrogel green bodies that can be further shaped into complex geometries after printing.image (c) 2023 WILEY-VCH GmbH