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In this study, we have successfully developed a unique 3D printing approach based on mask-image-projection stereolithography (MIP-SL) to fabricate structural ceramics microcomponents with low cost and high efficiency. Ultra-dense submicron crystalline ceramics without fierce grain growth could be obtained via tailoring the sintering kinetics. The ZrO 2 ceramic microcomponents reached the highest relative density (RD) of 99.7% with the average grain size of 0.52 μm upon sintering at 1550°C while the Al 2 O 3 ceramic microcomponents reached its highest RD of 98.31% with the average grain size of 2.6 μm upon sintering at 1600°C.Oxide ceramics microcomponents of fully flexible design can be produced easily without visible defects via the method developed in this study, which demonstrates significant potential in the applications of microelectromechanical systems, micro-optical electronics systems and micro-opto-electro-mechanical systems. The method developed in this study has addressed the problem successfully by healing the interlayer interface defects in densification process via the sintering kinetic window and microstructure evolution. The current work provides a promising opportunity to fabricate structural ceramic microcomponents with complex shape, high precision, and high surface smoothness. K E Y W O R D S

Reported herein is a novel ultrarobust and biomimetic hierarchically macroporous ceramic membrane that can achieve a high efficiency of up to 99.98% for oil−water separation, while the efficiency remains nearly unchanged even after 10 rounds of use and storage for up to 4 months. The macroporous ceramic membrane is prepared by combining surface hydrophobic coating with an emulsion-assisted template selfassembly of the modified Al 2 O 3 ceramic powder. The as-prepared ceramic membrane is a lightweight material with high strength because the relative density is only ∼1.02 g/cm 3 ; the compressive strength of the as-prepared ceramic membrane is expected to be 15-fold higher than that of the sample prepared using the traditional solid template approach even at a higher porosity due to the principle of self-assembly of Al 2 O 3 particles. It is the mechanism of self-assembly that has broken the traditional principle in ceramic preparation that leads to a perfectly dense packing structure. Moreover, the ceramic membrane maintained excellent oil− water separation efficiency, because of which even after its top layer was damaged by sand impingement, superfine particles could be separated using our macroporous membrane due to the featured interconnected pore structure. We anticipate that this example of the combination of a superwettability theory and a traditional ceramic material can provide an important application direction of advanced oil−water separation techniques.

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In this study, we developed a unique defect healing method for 3D printed ceramic compact via cold isostatic pressing (CIP) after debinding, and typical features of interlayer interface defects of 3D-printed zirconia compact were characterized and found to be reduced significantly. The characteristic sintering kinetics window and microstructure evolution of the healed sintered bodies were systematically investigated, which was found to be quite different from conventional shaping methods. The three sintering stages are probed by their feature microstructure details such as the mechanically flattening surface at the early sintering stage, the heterogeneous microstructure and high porosity in the interlayer interface region at the middle stage, and the slightly ripple-like structural features combined with the healed interlayer defects at the final stage. The evolution of the pore structure of the healed 3D printed bodies were traced and the mechanical properties such as the Young's modulus, hardness, and fracture toughness were measured to understand the significance of the heal effect. K E Y W O R D S3D printing, defects, kinetics, sintering Di An and Wei Liu contributed equally to this work.