Preparation of low shrinkage and high strength ceramic via extrusion-based 3D printing using inorganic binder

Extrusion-based 3D printing has been utilized as a general method for preparing ceramic structures and functional applications. However, widely-used polymer-based binders were unable to provide ceramic green bodies with high strength, and might introduce decomposition reactions during sintering. In this work, a polymer-free binder for extrusion-based 3D printing alumina ceramics was proposed, combined with analyzing the formation quality and corresponding properties. The results revealed that smooth extrusion and benign deposition could be realized in the formation owing to networks built from Al(H₂PO₄)₃ connecting with kaolin particles. Differing from pure polymer-based binder, relatively high bending strength and low shrinkage was obtained throughout drying and sintering process. Before and after sintering, the main phase remained as Al₂O₃ with some minor second phase detected. It is anticipated that this study could provide an alternative for binders in the extrusion-based 3D printing to improve the strength of ceramics after low-temperature sintering.