Additive manufacturing of ceramic composite cellular structures by spontaneous infiltration of copper oxide in alumina

Additive manufacturing (AM) of three-dimensional (3D) compact ceramic structures has extensive applications across various sectors, including energy, water, aerospace, and communications. However, several challenges, such as a limited selection of printable materials, low 3D printing resolution and a lack of multifunctionality hinder its widespread use. This work proposes a facile approach to infiltrate copper oxide (CuO) into a 3D-printed alumina (Al₂O₃) structure for enhancing the optical performance of Al₂O₃ ceramics. Various triply periodic minimal surface (TPMS)-based Al₂O₃ structures are fabricated with both vat photopolymerization and material extrusion techniques, specifically high-resolution projection stereolithography and cost-effective fused deposition modeling. Molten CuO spreads over the surface of Al₂O₃ preform volumetrically along with sintering and penetrates through the intergranular pores of Al₂O₃ driven by capillary force, which eventually results in a uniform distribution of CuO crystals within 3D porous Al₂O₃ structures. The in-situ mobilization and capillary infiltration of molten CuO among Al₂O₃ particles of different sizes is investigated to reveal the microstructure, optical-mechanical properties and thermal stability of CuO/Al₂O₃ composite structures. Owing to the recrystallization of CuO around the Al₂O₃ particles, the light absorptance of 3D composite structures is proportional to the CuO concentration and significantly enhanced in the wavelength range 250–2000 nm for solar applications. This AM approach for ceramic composite opens new avenues to functional 3D component manufacturing for a large variety of cutting-edge applications.