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 CO
2
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 CO
2
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.
In this study, a transition metal-based perovskite oxide catalyst with high CH3OH yield was successfully developed. The A-site substitution by Pr3+ in La1-xPrxMn0.6Ni0.4O3-δ can effectively adjust ...the activity of the perovskite catalysts for the direct conversion of CO2 and H2O into hydrocarbon fuels, especially CH3OH. Based on the designed photo-thermo synergetic photosynthesis strategy, the first hour CH3OH yield of La1-xPrxMn0.6Ni0.4O3-δ reached 3.97 mmol g−1, while only 0.24 μmol g−1 under normal photocatalysis mode. The synergistic photo-thermo catalysis was demonstrated to be a promising strategy for the future artificial photosynthesis development.
Display omitted
•In this study, a transition metal-based perovskite oxide catalyst with high CH3OH yield was developed.•The total carbon conversion rate can reach 6.73% with photo-thermo photosynthesis method.•The catalyst of La1-xPrxMn0.6Ni0.4O3-δ possesses abundant oxygen vacancies as active sites of CH3OH.
Vat photopolymerization (VPP) presents new opportunities for metals to achieve the design freedom of components. However, the material properties of copper powder and the inherent defects of the ...technology seriously hinder its application in high-precision metal additive manufacturing. Precision control is the key to obtaining minimal precision metal parts when copper is prepared by reduction photopolymerization. This paper employed variance analysis (ANOVA) and root mean square deviation (RMSD) to determine the significant parameters affecting dimensional accuracy and their optimal regions. The results show that printing accuracy is improved by optimizing exposure time, intensity, layer thickness, and sweeper moving speed. When the exposure time is 21 s, and the exposure intensity is 220 mW/cm2, a hole with a height of 1 mm and a diameter of 200 μm can be printed with a minimum size deviation of 51 μm. In addition, RMSD and ANOVA provide an effective method for realizing high-precision stereolithography 3D printing metal copper, expanding the material adaptation in the 3D printing metals field. The study highlights the potential of VPP as a method for preparing metals in future studies.
Zirconia ceramic octet-truss structures with various strut size and unit cell numbers were successfully fabricated through a DLP-based 3D printing method. The mechanical properties and energy ...absorption capacity under compressive load were investigated systematically. The sides of all cubes are 10 mm, the strut size was changed from 0.25 mm to 2 mm, cells number was in the range of 1(1 × 1 × 1)-125(5 × 5 × 5). It has been seen that the relative density, compressive strength and energy absorption increases with the increase of strut size when cell numbers remain the same. It can be concluded that the strength and energy absorption were affected by the relative density, strut size and the stacking mode of the unit cells. So far, with this study, a high compressive strength of 75.3 MPa and a reasonably good energy absorption of 6.76 × 105 J m−3 can be achieved at a relative density of 48.57%.
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.
Currently, a significant challenge in the fabrication of ceramic dental prostheses via vat photopolymerization lies in the utilization of slurries composed of organic monomers, which compromises ...environmental sustainability and impedes commercial viability. In this research, we successfully develop a low-viscosity aqueous zirconia ceramic suspension with a solid loading of 40 vol% and 20 vol% deionized waters, incorporating 3 wt% dispersant and 0.5 wt% photoinitiator for printing dental crowns using vat photopolymerization. The resulting green bodies require only water washing to remove unreacted material. The printed ceramics demonstrate an average flexural strength of 708 MPa, a relative density of 98.3 %, and a Vickers hardness of 14.7 GPa. A dental crown is ultimately fabricated with an accuracy of 92.8 %. This study demonstrates that zirconia ceramics fabricated by vat photopolymerization with aqueous suspension exhibit excellent mechanical properties and accuracy, highlighting their potential for broad applications in dental restorations through an environmentally sustainable approach.
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.
Five kinds of 2D chiral ceramics of 3 mol% yttria-stabilized tetragonal ZrO2 (3Y-TZP) material with an extensive relative density range was fabricated by an additive manufacturing technique based on ...the digital light processing (DLP) system. The in-plane compressive behaviours of the chiral structures were investigated with a uniaxial compression test. The effects of geometric parameters, including the ligament length-radius ratio and the wall thickness-radius ratio, were studied carefully through experiments. Furthermore, the relationships between Poisson's ratios and relative densities of the five chiral structures were obtained by finite element analysis. The results illustrated that increasing the relative density, like decreasing L/r or increasing t/r, is an excellent way to increase the mechanical properties of chiral ceramics, while decreasing L/r is a better way to increase the energy absorption capacity for chiral ceramics from an engineering perspective. Anti-tetrachiral ceramics own the best energy absorption capacity due to their strong deformation abilities brought by the deformation mode. The Poisson's ratio of 2D chiral structures also varies with the relative density.
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.
Silicon carbide (SiC) is widely used in various industrial fields for its excellent properties. Vat photopolymerization (VP) technology stands out in the fabrication of SiC ceramics due to its ...enhanced design flexibility and capability to produce intricate geometries. However, the excessive residual carbon content in VP technology directly affects the sintering performance of SiC ceramics, leading to cracking and deformation defects. To address this issue, we systematically studied the residual carbon content of SiC under different debinding atmospheres in forming by VP technology. We found that the debinding atmosphere can effectively control the residual carbon content in SiC ceramics. Residual carbon exists in samples with a lower degree of defect, promotes grain growth, reduces neck size, and results in flexural strength of 253.13 MPa after pressureless sintering. This research promotes the application of VP technology in SiC ceramics and opens up a new avenue for the development of high-performance SiC ceramics.
PDF
