High-precision printing of intricately shaped kaolin ceramics by digital light processing: Impact of solid content on microstructure and densification

Abstract

High-precision microfabrication of functional ceramics with complex shapes and tailored properties currently arouse significant attention, but maintaining dimensional accuracy is still a research challenge. Herein, an innovative digital light processing (DLP) 3D technology is employed to fabricate calcined kaolin (Al2O3·2SiO2) ceramic with intricate structures, achieving high precision and densification. To illustrate the potential of different solid content slurries (43, 45, 46.2, and 47.5 vol%), and the curing thickness with tuned exposure time (8s, 10s, and 12s), we investigated their impact on physical properties and microstructures. The results show that the optimal sintering at 1200 °C achieved an exceptionally high density 2.38 g/cm3, with low shrinkage (17.35 %) along XY-direction and porosity reaching up to 15.53%. The highest level of solids slurry at 47.5 vol% increased the densification and open porosity. For all solid contents, the shrinkage along the Z-direction was exceeded compared to the XY-direction. A comprehensive evaluation of sintered morphologies, including their topography and chemical composition. The EDX mapping showed that kaolin ceramics have excellent stability at high temperatures. The highest flexural strength of DLP printed specimen at temperature (1200 °C) is 71.60 MPa, whereas that of the diamond porous structure is 6.66 MPa. Our work sheds light on high-precision microfabrication of complex shapes with unparalleled accuracy and efficiency, paving the way for high-performance functional ceramic materials.

Keywords

• DLP 3D printing
• Kaolin ceramic
• Solid content
• Complex shapes
• Shrinkage