Damage-tolerant 3D-printed ceramics via conformal coating
SM Sajadi and L Vasarhelyi and R Mousavi and AH Rahmati and Z Konya and A Kukovecz and T Arif and T Filleter and R Vajtai and P Boul and ZQ Pang and T Li and CS Tiwary and MM Rahman and PM Ajayan, SCIENCE ADVANCES, 7, eabc5028 (2021).
Ceramic materials, despite their high strength and modulus, are limited in many structural applications due to inherent brittleness and low toughness. Nevertheless, ceramic-based structures, in nature, overcome this limitation using bottom-up complex hierarchical assembly of hard ceramic and soft polymer, where ceramics are packaged with tiny fraction of polymers in an internalized fashion. Here, we propose a far simpler approach of entirely externalizing the soft phase via conformal polymer coating over architected ceramic structures, leading to damage tolerance. Architected structures are printed using silica-filled preceramic polymer, pyrolyzed to stabilize the ceramic scaffolds, and then dip-coated conformally with a thin, flexible epoxy polymer. The polymer-coated architected structures show multifold improvement in compressive strength and toughness while resisting catastrophic failure through a considerable delay of the damage propagation. This surface modification approach allows a simple strategy to build complex ceramic parts that are far more damage-tolerant than their traditional counterparts.
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