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In this study, four types of triply periodic minimal surface (TPMS) were implemented to create cellular ceramics via digital light processing (DLP) technology, namely p-cell, gyroid, IWP and s14. The mechanical properties of these TPMS structures were investigated experimentally. Results showed that compressive strength of TPMS structures increases with relative density. IWP and s14 structures exhibit similar mechanical response under stress. In general, all TPMS structures can sustain >2% strain without failure and the compressive strength followed the order of s14 > IWP > gyroid > p-cell. The s14 structure can reach a high compressive strength of 105 MPa at a structural density of 30.5 % while gyroid structure can provide a compressive strength of 5.6 MPa at a very low structural density of 6.7 %. The porosity dependence of Young’s modulus of sintered zirconia TPMS demonstrated that the Pabst-Gregorova exponential relation can provide a better prediction than the classical Gibson-Ashby model.

High performance hydroxyapatite (HA) ceramics with excellent densification and mechanical properties were successfully fabricated by digital light processing (DLP) three-dimensional (3D) printing technology. It was found that the sintering atmosphere of wet CO2 can dramatically improve the densification process and thus lead to better mechanical properties. HA ceramics with a relative density of 97.12% and a three-point bending strength of 92.4 MPa can be achieved at a sintering temperature of 1300 , which makes a solid foundation for application ℃ in bone engineering. Furthermore, a relatively high compressive strength of 4.09 MPa can be also achieved for a DLP-printed p-cell triply periodic minimum surface (TPMS) structure with a porosity of 74%, which meets the requirement of cancellous bone substitutes. A further cell proliferation test demonstrated that the sintering atmosphere of wet CO2 led to improve cell vitality after 7 days of cell culture Moreover, with the possible benefit from the bio-inspired structure, the 3D-printed TPMS structure significantly improved the cell vitality, which is crucial for early osteogenesis and osteointegration.

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.

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.

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 La0.8Sr0.2MnO3 (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.

The effect of heat treatment on the in-line transmittance of BaZr 0.5 Ce 0.3 Y 0.2 O 3−δ (BZCY532) ceramics prepared by spark plasma sintering method was investigated. The loss of Ba in transparent BZCY532 ceramics is the key reason for the loss of transmittance during the annealing process. This problem can be effectively alleviated by using a powder bed of BZCY532. Heat treatment atmospheres, wet air and dry air, were also found to be critical for obtaining high quality transparent ceramics. A highly transparent BZCY532 ceramic with the in-line transmittance (T in ) of 71.4% at 2000 nm can be obtained by using SPS method followed by an annealing in powder bed at 1500 °C in wet air.

In practical Lamb wave-based damage detection, the spatial resolution of Lamb waves is usually restricted by not only dispersion but also the space duration of excitation waveforms, i.e., the initial spatial resolution (ISR) for the signals before travelling. To overcome this problem, a signal domain transform (SDT) method is presented in this paper. In SDT, the original dispersive Lamb wave signals are transformed from the time to distance domains, with the time-distance scaling on the excitation waveforms particularly modified. Then, both dispersion compensation and ISR enhancement can be actualized to efficiently improve the signal spatial resolution. A high resolution damage imaging based on SDT is further developed. The efficiency of SDT and SDT-based imaging methods has been well demonstrated by the experimental study on an actual complicated aircraft wing beam.

The ceramic honeycomb sandwich structures of 3 mol% yttria-stabilized tetragonal ZrO2 (3Y-TZP) material were fabricated by an additive manufacturing technique based on the digital light processing (DLP) system. The bending behaviour of hexagonal and square honeycomb sandwich structures was investigated with three-point bending test. The effects of geometric parameters, including the thickness of the face-sheet, the height of the cell, the thickness of the cell wall and the size of the cell, were studied through experiments carefully. The results illustrated that the bending strength of the ceramic honeycomb sandwich structure can reach 170 MPa at a relative density of 41.72%. The geometric parameters of the honeycomb core were more critical than the sandwich face-sheet. The cell size, cell wall thickness and cell height were found to be the preferred geometric parameter for justifying the bending resistance performance of the ceramic sandwich panel. Square honeycomb demonstrated better bending performance than the hexagonal honeycomb. This study provides a new basis for further studies on the ceramic lightweight structures.

A novel facile approach has been developed to prepare graphene-like α-Co(OH)2 two-dimensional ultrathin nanosheets. The layered hydrotalcite-like α-Co(OH)2 aggregates were successfully exfoliated in formamide solution in a constant temperature oscillator. The influence of exfoliation on the thickness and surface structure of the Co(OH)2 monolith was analyzed by scanning electron microscopy and transmission electron microscopy. After the exfoliation process, the electrochemical performances of the 2D α-Co(OH)2 nanosheets were tested by cyclic voltammetry, galvanostatic discharge/charge, and electrochemical impedance spectroscopy. Impressively, the charge/discharge study shows that the exfoliated sample is capable of delivering a high specific capacitance of 952 F g–1 at a current density of 5 mA cm–2 and maintains 48 % of the capacitance when the current density is as high as 50 mA cm–2. In addition, the exfoliated Co(OH)2 nanosheets also exhibited excellent cycling stability and is an excellent electrode material for high-performance supercapacitors. Our work not only presents a cost-effective and scalable method for the synthesis of α-Co(OH)2 nanosheets with a high surface area, but also holds promise for the synthesis of a series of other graphene-like laminar structures with high specific surface areas for electrochemical energy storage, catalysis, gas sensing, and other applications.