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Additive manufacturing of PDCs: (a) preparation of photosensitive resins for the ceramic precursor; (b) design of CAD models with varied lattice structures; (c) DLP 3D printing of the as-prepared resin; (d) pyrolysis of the as-printed resin components in a tube furnace under an argon atmosphere; (e) as-pyrolysed SiOC ceramic components with lattice structures.
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Lightweight and high-strength polymer-derived SiOC ceramics with varied lattice structures have been successfully produced using different polysiloxanes as preceramic polymers (PCPs) via photopolymerisation-based digital-light-processing 3D printing and pyrolysis. Photocurable precursor resins were prepared by simple mixing of polysiloxanes with ph...
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... microstructural, mechanical, and chemical properties of the ceramic samples obtained after pyrolysis at different temperatures were comprehensively studied, and the results showed that lattice-structured SiOC ceramics with great forming qualities, crack-free surfaces, and prominent specific strength were realised. Figure 1 depicts the fabrication process of lattice-structured SiOC ceramic components, including the preparation of precursor resins, the design of 3D models with lattice structures, and DLP 3D printing and pyrolysis treatment. ...
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... changes in functional groups after photocuring and pyrolysis at different temperatures was studied using FT-IR spectroscopy, as shown in Figure 10. The peak at 699.48 cm −1 corresponds to the out-of-plane bending vibration of C-H from phenyl, and the peaks at 2934.01 and 3073.29 cm −1 correspond to the stretching vibrations of C-H from methyl and phenyl, respectively. ...
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... the pyrolysis temperature increases, the structural rearrangement leads to an energy increment for the vibration of every bond, resulting in a blueshift and broadening of almost all of the absorption peaks. Figure 11 shows the Raman spectra of the cured resin and pyrolysed PDCs. The main peaks located at 1335 and 1605 cm −1 pertain to the D mode and G mode of free carbon, respectively. ...
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... verified by X-ray photoelectron spectroscopy (XPS) in Figure 12, the element composition of PDCs was determined of 18.64 atomic percent at% Si, 23.78 at% O and 57.57 at% C, or SiO 1.28 C 3.08 . ...
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... phase changes of the PCPs and SiOC ceramics after pyrolysis at 600-1000°C were studied using XRD analysis, as shown in Figure 13. With increasing pyrolysis temperature, PCP changed into amorphous SiOC ceramics, with only one broad peak observed at 16-25°. ...
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... structures were designed and successfully printed, as shown in Figure 14(a-c). By controlling the amount of TMPTA diluent/monomer in the appropriate range, sufficient curing strength of the precursor resin can be guaranteed and DLP 3D printing of complex structural parts can be achieved. ...
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... post-curing in UV light of 52 mW/cm 2 intensity for 60 s, the resin models were pyrolysed at 600, 800, and 1000°C, respectively in an argon atmosphere. Intact lattice-structured SiOC ceramic components with a high surface quality and a fine internal structure were obtained (Figures 14 (d-f)). The inner channels were well interconnected, without clogging, suggesting that structural details were maintained (Figure 14(g-i)). ...
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... lattice-structured SiOC ceramic components with a high surface quality and a fine internal structure were obtained (Figures 14 (d-f)). The inner channels were well interconnected, without clogging, suggesting that structural details were maintained (Figure 14(g-i)). ...
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... microstructures of lattice-structured SiOC ceramics are shown in Figure 15, where (a, d, g) show the octet truss structure, (b, e, h) the trunc octa structure, and (c, f, i) the rhombus dodecahedron structure at different magnifications. The skeletons of the printed SiOC ceramic components are of high density and good shape, with no obvious defects ( Figure 15(h and i)). ...
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... microstructures of lattice-structured SiOC ceramics are shown in Figure 15, where (a, d, g) show the octet truss structure, (b, e, h) the trunc octa structure, and (c, f, i) the rhombus dodecahedron structure at different magnifications. The skeletons of the printed SiOC ceramic components are of high density and good shape, with no obvious defects ( Figure 15(h and i)). The thickness of each layer after contraction was about 60 μm. ...
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... thickness of each layer after contraction was about 60 μm. The distinctive step effect can be observed on the contoured surfaces of the samples, which resulted mainly from the software slice profile data (Figure 15(e and f)). Such effects can be prevented by means of thinning of the layer thickness or optimisation of the slicing procedure. ...
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... effects can be prevented by means of thinning of the layer thickness or optimisation of the slicing procedure. Nevertheless, very few pores at microscale can be identified at high magnification since the escape of small-molecule gases occurs during pyrolysis, which may have only a small effect on the mechanical properties of SiOC ceramics (Figure 15(g)). ...
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... variation in phase organisation and microstructure resulting from different pyrolysis temperatures may lead to varied linear shrinkage and mass loss at the macroscopic scale. The linear shrinkage results shown in Figure 16(a) were calculated as averaged values with standard deviations based on the linear shrinkages measured along the three directions of the samples. The very small standard deviations (i.e. ...
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... very small standard deviations (i.e. error bars) shown in Figure 16(a) for all the three pyrolysis temperatures further indicate a uniform shrinkage occurred during pyrolysis along the three directions. From the observation of pictures (Figure 14) and SEM images (Figure 15), it can be further confirmed that no obvious cracks were found in the pyrolysed samples at either macro-or micro-scales. ...
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... bars) shown in Figure 16(a) for all the three pyrolysis temperatures further indicate a uniform shrinkage occurred during pyrolysis along the three directions. From the observation of pictures (Figure 14) and SEM images (Figure 15), it can be further confirmed that no obvious cracks were found in the pyrolysed samples at either macro-or micro-scales. ...
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... bars) shown in Figure 16(a) for all the three pyrolysis temperatures further indicate a uniform shrinkage occurred during pyrolysis along the three directions. From the observation of pictures (Figure 14) and SEM images (Figure 15), it can be further confirmed that no obvious cracks were found in the pyrolysed samples at either macro-or micro-scales. ...
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... linear shrinkage with increasing temperature increased from 36.49% to 42.01%, while the mass loss increased from 65.92% to 70.37% (Figure 16(a)), suggesting a progressive densification of latticestructured SiOC ceramics. However, both linear shrinkage and mass loss varied only slightly in the range 800-1000°C, proving that the phase organisation and microstructure tend to be stable in this temperature range. ...
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... both linear shrinkage and mass loss varied only slightly in the range 800-1000°C, proving that the phase organisation and microstructure tend to be stable in this temperature range. The density and porosity were measured according to Archimedes' method (Figure 16(b)). As the pyrolysis temperature rose from 600 to 1000°C, the skeleton density increased from 1.06 to 1.60 g/cm 3 , overlapping the SiO x C y theoretical density range of 1.17-2.13 ...
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... 3 to a reasonable extent. As shown in Figure 13, the crystallisation of the SiOC took place at temperatures above 800°C, resulting in the growth and rearrangement of the ceramic grains. It would decrease the number of particles surrounding the pores, which finally disappeared when the number is lower than the coordination number. ...
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... the porosity decreased from 7.09% to 3.64%, while the relative density increased from 92.91% to 96.36%, suggesting that high densification of the SiOC lattice-structure was achieved. Table 2. Elemental composition of PDCs in this work and references ( Eckel et al. 2016;Fu et al. 2018; Figure 13. XRD patterns of PCPs pyrolysed at 600-1000°C. ...
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... mechanical properties of the octet truss latticestructured SiOC ceramics, including the skeleton's localised hardness and elastic modulus as well as the effective structural compressive strength and effective elastic modulus, were measured, and the results are given in Table 3 and shown in Figures 17 and 18, respectively. Nanoindentation tests were carried out with a maximum load of 5000 μN and a loading rate of 0.3 nm/s. ...
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... the stress required for further deformation decreases and the stain growth rate accelerates with an increase in stress. As can be seen from Figure 17, the load-displacement curves in both the perpendicular (Figure 17(a)) and hierarchical directions (Figure 17(b)) are all typically smooth, suggesting a dense and uniform solid state of the pyrolysed samples. ...
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... the stress required for further deformation decreases and the stain growth rate accelerates with an increase in stress. As can be seen from Figure 17, the load-displacement curves in both the perpendicular (Figure 17(a)) and hierarchical directions (Figure 17(b)) are all typically smooth, suggesting a dense and uniform solid state of the pyrolysed samples. ...
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... the stress required for further deformation decreases and the stain growth rate accelerates with an increase in stress. As can be seen from Figure 17, the load-displacement curves in both the perpendicular (Figure 17(a)) and hierarchical directions (Figure 17(b)) are all typically smooth, suggesting a dense and uniform solid state of the pyrolysed samples. ...
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... typical stress-strain curves for the samples pyrolysed at different temperatures are shown in Figure 18 (a). On the other hand, the effective uniaxial compressive strength increased significantly from 1.54 to 19.08 MPa, showing an order of magnitude improvement when the pyrolysis temperature rose from 600 to 1000°C (Figure 18(b)). ...
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... typical stress-strain curves for the samples pyrolysed at different temperatures are shown in Figure 18 (a). On the other hand, the effective uniaxial compressive strength increased significantly from 1.54 to 19.08 MPa, showing an order of magnitude improvement when the pyrolysis temperature rose from 600 to 1000°C (Figure 18(b)). The effective elastic modulus of the whole lattice structure, which was extrapolated by fitting the stress-stain curve, increased from 7.98 to 38.96 GPa. ...
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... specific compressive strength to density ratios of the SiOC lattices prepared in this study were compared with those of other lattices, as well as honeycombs made from Al 2 O 3 , ZrOC, SiOC, and SiC, as shown in Figure 19 (Colombo, Hellmann, and Shelleman 2001;Agrafiotis et al. 2007;Bird and LaPointe 2013;Bauer et al. 2014;Meza, Das, and Greer 2014;Eckel et al. 2016;Zanchetta et al. 2016;Fu et al. 2018Liu et al. 2018). The silicon oxycarbide lattice manufactured in this study showed a prominent specific compressive strength to density ratio of up to 5.74 × 10 4 N·m/kg, which is distinctly higher than that of other materials of similar density. ...
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... addition, in that study, enriched SiC nanocrystalline precipitated from SiOC after pyrolysis at 1300°C, and the resultant ceramics would have had strength enhancement with a dual amorphous-crystalline phase. As can be seen from Figure 19, the specific strength of SiOC lattices can be further promoted toward the theoretical limit by choosing precursor polymers with a higher C-O ratio and a suitable pyrolysis temperature to facilitate the formation of nanocrystalline SiC. ...
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... Lattice materials are artificially created structures that combine lightweight and robust mechanical properties due to their porous nature, inspired by natural architects. They are designed at a microstructural level to exhibit distinctive mechanical characteristics such as negative Poisson's ratio [1], negative stiffness [2], and a high strength-to-weight ratio [3]. Various lattice materials have been created over the years, such as truss- [4], surface- [5], and plate-based lattice materials [6]. ...
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... structuring processes, as well as the difficulty of achieving sophisticated three-dimensional architectures 9,10 . Emerging 3D printing technology, also known as additive manufacturing (AM), uses digital designs and layer-by-layer accumulation to construct complex architectures via serial deposition, thereby streamlining manufacturing processes [11][12][13][14][15][16] . Current high-resolution glass 3D printing techniques typically involve precise and localized photopolymerization, which solidifies liquid polymer resin into a solid phase. ...
... In accordance with Fig. 5d, compressive strengths of 33.72 MPa, 40.85 MPa, and 29.86 MPa were attainable at each stage. As depicted in Fig. 5e and Supplementary Table 5, a compressive strength versus density Ashby chart was plotted to facilitate intuitive comparisons between OμSL 3D-printed fused silica glass microlattices and other high-temperature architected materials 14,[44][45][46][47][48][49][50][51][52] . The specific strength of the fused silica glass microlattices produced by OμSL was 1.22 × 10 5 N m kg −1 , which significantly outperformed other materials of comparable density. ...
... e Ashby chart on compressive strength versus density. OμSL 3D-printed fused silica glass microlattices with high specific strength in this work (red star) were compared with other reported high-temperature architected materials14,[44][45][46][47][48][49][50][51][52] . ...
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... In addition, they contain hydrogen as a side group [36]. Polyorganosilazanes can be formulated with initiators, catalysts, or fillers to form processable matrix composites that can be fabricated by casting [37,38], coating [4,39], or additive manufacturing [18,[40][41][42][43]. Crosslinking is usually carried out thermally [44,45] or photochemically [46] after processing to reduce the loss of low-molecular-weight components and consequently leading to a high ceramic yield after pyrolysis at high temperature [47]. ...
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... One direction in the field utilizes preceramic polymers to improve the issues with low solids content and/or RI of powders, but is limited to feature sizes (∼<1 mm) due to off-gassing and shrinkage during the cure and pyrolysis steps, respectively. [195][196][197][198][199] Fine feature resolution (in the range of ∼10-20 μm) is an advantage but limitations in composition (mainly oxides) and/or part thickness (<∼10 mm) are current challenges with commercially available feedstock. 200 Despite these limitations, it remains the most advanced in terms of commercial equipment and ceramic feedstock (3DCeram, Admatec, Lithoz, and Tethon 3D) and ability to make complex shapes (e.g. ...
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... In the micrograph, no distinguishable surface cracks, voids, nor large defects are noticeable. When comparing the resultant PDCs with other ceramics manufactured using similar precursors and manufacturing methodologies this is as expected [28,33]. However, the lack of visible defects does not imply that the structure is altogether defect free and due to the nature of pyrolysis may contain nanoscale pores due to gas release during the polymer-to-ceramic conversion [6]. ...
The 3D printing of pre-ceramic polymers that can be pyrolyzed into functional ceramics has recently become a focus for advanced ceramic applications requiring complex geometries. In this work, a new methodology for 3D printing SiCNO ceramic materials derived from a novel pre-ceramic photopolymer feedstock utilizing a thiol-ene reaction is introduced. The printed parts are pyrolyzed to amorphous SiCNO and the physical and mechanical properties of the final ceramic are measured. Pyrolysis of the pre-ceramic produced a SiCNO ceramic with 41% ceramic yield and shrinkage of 24% with a hardness measured at 6.6 GPa ± 0.3 GPa.
... Recently, PCPs have been extensively used in DLP. The authors of the work of Li et al. 65 developed photocurable PCPs by mixing organosilicon powders with monomer, photoinitiator, dispersant, and diluent. The results showed that increasing pyrolysis temperatures can be helpful to improve the mechanical properties of the final part and obtain dense and crack-free parts. ...
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Owing to freedom of design, simplicity, and ability to handle complex structures, additive manufacturing (AM) or 3D printing of ceramics represents a promising enabling technology and has already been used to produce geometrically complex ceramic components and ceramic metamaterials. Consequently, novel applications for additively manufactured ceramics, which leverage their structural, high temperature, and chemical-resistant properties, have been proposed in areas ranging from electrical engineering and micro/nanoelectronics to chemical engineering to biology. Polymer derived ceramics (PDCs) represent a relatively new class of materials within additive manufacturing. PDCs enable the development of ceramic parts patterned via low-cost polymer 3D printing methods followed by pyrolysis in a high temperature process in which the polymer itself forms a ceramic often in the absence of any ceramic filler. PDCs have served as a feedstock for various 3D printing techniques for which a wide range of physiochemical factors can be tailored to optimize the ceramic manufacturing processes. In particular, the silicon and carbon-rich polymeric microstructure of PDCs offers a high degree of tunability and potential to achieve a closely defined combination of functional, thermomechanical, and chemical properties. In this review, we cover mechanisms underlying the design and manufacture of ceramics via 3D printing and pyrolysis of preceramic polymers, focusing on chemical formulations, printing technologies, and the mechanical performance of the ceramic network from microscale to scale. We also summarize experimental data from the literature and present qualitative and quantitative comparisons between different AM routes to provide a comprehensive review for 3D printing of PDCs and to highlight potential future research.
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... Li et al. prepared three types of polysiloxane as photocurable precursor resins and obtained lattice structured SiOC ceramics using a DLP printer; the measured results showed that the linear shrinkage and mass loss [376] were 42.01% and 70.37%, respectively. In addition, the authors indicated that the lattice produced in the study showed an exceptional specific compressive strength to density ratio of up to 5.74 × 10 4 N m/kg, which was distinctly higher than that of other cellular materials [373]. The compressive strength was~2 times higher than the SiC honeycomb reported by Agrafiotis et al. [374]. ...
Four-dimensional (4D) printing, an innovative extension of three-dimensional (3D) printing, is defined as the additive manufacturing technology of intelligent components with controllable stimuli-responsive characteristics. The 4D-printed components can automatically and controllably change their shapes, properties, and/or functionalities with time in response to external stimuli, such as heat, moisture, light, PH, magnetism, and electricity. 4D printing integrates the design of structures’ intelligent behaviors into the fabrication processes, realizing integrated manufacturing of materials, structures, and functionalities. It has aroused worldwide attention in the academic and industrial communities since it was first proposed in 2013. Stimuli-response materials play a critical role in the relation of 4D printing. The stimuli-responsive characteristics of the 4D-printed components mainly depend on the properties of used stimuli-responsive materials and their combination and arrangement in 3D space. However, so far only limited stimuli-responsive materials for 4D printing have been developed, which greatly restricts to tap of the application potential of 4D printing. Thus, stimuli-responsive materials for 4D printing have become the hot and key spots of research in academia and engineering fields. In this chapter, after an introduction of the definition and prospect of 4D printing, the research advances in available stimuli-responsive materials for 4D printing were reviewed in detail in three categories: polymers and their composite materials, metals and their composite materials, and ceramics and their composite materials. This chapter may enhance our understanding of the 4D printing of stimuli-responsive materials and inspire further innovative ideas for the design of materials for 4D printing.
