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Vat photopolymerized 3D printing technology can be used to fabricate ceramics with complex shapes. However, the extensive use of photosensitive resins as binders is not conducive to achieving crack-free ceramic green parts, especially the Si 3 N 4 ceramics with the weak interlayer bonding. In this work, the influence of different debinding atmosphere on the pyrolysis process of organics in vat photopolymerization 3D printed Si 3 N 4 green parts was investigated. The results showed that the use of 95 vol% N 2 +5 vol% H 2 atmosphere can effectively inhibit the cracking during the debinding process, especially the wall thickness of the 3D printed defect-free Si 3 N 4 green body was successfully increased to 5 mm, and the obtained sintered Si 3 N 4 ceramics exhibited higher true densities and better mechanical properties. The debinding atmospheres proposed in the current work provided additional options of debinding atmosphere for achieving high-performance 3D printed Si 3 N 4 ceramics and are expected to be expanded to other photosensitive slurry systems, with the potential to enable the production of ceramic components with the larger wall thicknesses. [ABSTRACT FROM AUTHOR]

Inspired by the double-helix structure of biological DNA, low-volume fraction and high-strength Al 2 O 3 twisted honeycomb structures with characteristics similar to those of helical structures in the z -axis were prepared by digital light processing 3D printing technology. As the twist angle increased, the compressive strength of the fabricated Al 2 O 3 structure decreased, and the deformation mechanism of the Al 2 O 3 structures gradually changed from stretching-dominated to bending-dominated, which can be predicted by the Gibson–Ashby model. The relationship between the effective elastic modulus and the volume fraction that can be modified by varying the wall thickness was described by the Pabst–Gregorova exponential relationship. The compressive strength of the Al 2 O 3 structure with a twist angle of 0° can reach 62.4 MPa at a volume fraction of 13.3%, providing guidance to optimize lightweight structures of ceramics. [ABSTRACT FROM AUTHOR]

Digital light processing 3D printing can be applied to fabricate complex silicon nitride (Si 3 N 4) components. However, because of the surface hydroxyl groups and large refractive index, it is still a foremost challenge to realize a stable photosensitive Si 3 N 4 slurry with combined benefits of low viscosity and large curing depth. In this study, we propose a new formulation strategy to prepare Si 3 N 4 slurry. Starting from the optimization of monomer ratio, we have systematically optimized powder particle size, dispersant and photoinitiator on the rheological properties and curing properties of Si 3 N 4 slurry. Specifically, we have fabricated a stable photosensitive Si 3 N 4 slurry (48 vol%) with a viscosity of 2.09 Pa s (30 s−1), a critical curing energy of 126.09 mJ/cm2 and a maximum curing depth of 80 µm. Finally, based on this optimized slurry, we have successfully obtained complex Si 3 N 4 green body with no defect, which demonstrates great potential to fabricate arbitrary complex ceramic components for various applications. [ABSTRACT FROM AUTHOR]

Herein, translucent alumina ceramics with fine complex geometric shapes are successfully fabricated by a digital light processing (DLP) process followed by vacuum sintering. The interlayer bonding condition is the key for preparing high‐quality translucent alumina for this layer‐by‐layer additive manufacturing (AM) method. The curing characteristics of alumina suspensions are carefully investigated by curing depth and polymerization conversion behavior. It is clear that the residual stress resulted from the polymerization process is more critical than the curing depth for selecting optimum curing time. Finally, high‐quality translucent alumina ceramic and complex structures are realized using this novel AM technique. It reveals that DLP 3D printing method can be a promising technology for the fabrication of transparent ceramics. [ABSTRACT FROM AUTHOR]

The development of photosensitive slurries for additive manufacturing has attracted great interest due to their correlation with the final properties of the fabricated parts. This paper focus on the printing quality control in digital light processing (DLP) 3D printing of advanced ceramics. Systematic experiments were performed to assess the effects of the exposure time and printing angle on the three-point bending strength of the fabricated samples. The exposure time affected the bending strength of the printed zirconia ceramic dramatically. When the weak exposure time is 1 s and the strong exposure time is 13 s, the average bending strength can reach 580 MPa while Weibull modulus can reach 8.84. Meanwhile, the printing angle also affected the bending strength mechanical sample printed at 45° exhibits the worst performance. [ABSTRACT FROM AUTHOR]

The high integration density of microelectronic devices leads to local heat accumulation, and effective heat dissipation and signal transmission of packaging materials have become the primary issues to be solved. However, existing polymer materials have difficulty meeting the requirements due to their unsatisfactory thermal conductivity and thermal expansion properties. In this work, we proposed the use of digital light processing (DLP) printing technology to construct a triply periodic minimum surface (TPMS) skeleton, and a continuous and efficient heat conduction path was successfully constructed in epoxy resin by impregnating h-BN on the skeleton surface. When the loading of h-BN was 20 vol%, the thermal conductivity of the TPMS(SiO 2)@BN/EP(BN) composites was 1.86 W/(m·K), which was 786 % higher than that of pure epoxy resin. In addition, the thermal expansion coefficient of the composites decreased by more than 70 %. At the test frequencies of 3∼10 MHz, the composites showed stable dielectric properties, and the dielectric constant was always maintained in a low range, between 3.85 and 4.15. This work has realized the transformation of the method for constructing a heat conduction path from disordered to ordered and from random to repeatable. This provides a new strategy for the selection of microelectronic packaging materials. [ABSTRACT FROM AUTHOR]

In this work, 8mol% yttria-stabilized zirconia (8YSZ) ripple-shaped electrolytes have been prepared by digital light processing (DLP) 3D printing and their electrochemical performances have been investigated. The total conductivities of flat samples printed at different angles were tested firstly to confirm that there is no huge influence on the electrochemical performance from the printing itself. Then, by using ripple-shaped electrolytes, primary cells were assembled and their electrochemical performance were investigated. Compared with the reference flat cell, an improvement of ~32% was achieved in the power density for the same thickness of the electrolyte (~200 µm) at 800 °C. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Solid Oxide Fuel Cells (SOFCs) are environmentally efficient energy conversion devices, but are partially limited by the complicated fabrication procedure. In this work, dense 8 mol% yttria-stabilized zirconia (8YSZ) ceramics were successfully realized through a DLP (digital light processing) stereolithography method and the electrolyte self-supported fuel cell was also tested at 800 °C. The sintering behavior of the as-printed planar samples were investigated and a fully dense ceramic can be achieved at 1450 °C. The total conductivity of the sintered 8YSZ can reach 2.18 × 10−2 S cm−1 at a test temperature of 800 °C, which is acceptable for practical application. For the electrolyte self-supported fuel cell test, a power density of 114.3 mW cm−2 can be achieved when Ni-8YSZ cermet and La 0.8 Sr 0.2 MnO 3 (LSM) were used as anode and cathode. It was demonstrated that 3D printing is a promising processing technique to build up electrolyte self-supported SOFCs with desired structure for the future development. [ABSTRACT FROM AUTHOR]