Microstructural designs of spark-plasma sintered silicon carbide ceramic scaffolds

Román-Manso, Benito; Pablos, Á. De; Belmonte, Manuel; Osendi, M.I.; Miranzo, P.

doi:10.3989/cyv.132014

Cited by 21 publications

(11 citation statements)

References 20 publications

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“…As a final step, the 3D structures were densified by pressureless Spark Plasma Sintering (SPS) at 1700 • C in Ar. As shown in [24], these sintering conditions lead to full densification of the ceramic materials. Scanning Electron Microscopy (SEM) images and optical micrographs of the final sintered micro-lattices are shown in Figs.…”

Section: Methodsmentioning

confidence: 96%

“…The examined SiC micro-scaffolds were fabricated by Robocasting using a similar additive manufacturing process as described in [3,24]. In brief, an aqueous colloidal paste (containing attrition milled SiC powders with 7 wt.% Al 2 O 3 and Y 2 O 3 sintering additives plus organic additives) was printed through a robotically controlled nozzle into an oil bath, so that a regular architecture was obtained layer-by-layer, consisting of a linear array of parallel filaments in each layer.…”

Section: Methodsmentioning

confidence: 99%

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Ultrasonic bandgaps in 3D-printed periodic ceramic microlattices

et al. 2018

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The transmission of longitudinal ultrasonic waves through periodic ceramic microlattices fabricated by Robocasting was measured in the 2-12MHz frequency range. It was observed that these structures (scaffolds of tetragonal and hexagonal spatial arrangements with periodicity at length-scales of ∼100μm) exhibit well-detectable acoustic band structures with bandgaps. The locations of these gaps at relatively high frequencies were shown to be in close agreement with the predictions of numerical models, especially for tetragonal scaffolds. For hexagonal scaffolds, a mixing between longitudinal and shear polarizations of the propagation modes was observed in the model, which blurred the matching of the calculated band structures with the experimentally measured bandgaps.

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Section: Methodsmentioning

confidence: 96%

Section: Methodsmentioning

confidence: 99%

Ultrasonic bandgaps in 3D-printed periodic ceramic microlattices

et al. 2018

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“…Furthermore, the oxygen content in the raw powders (as a SiO 2 passivating scale) is crucial for the formation of the secondary phase, since crystallization takes place for oxygen contents below 2 wt% but it remains amorphous when employing nanosized powders (with 4.1 wt% of oxygen). Secondary phase crystallization has also been reported for similarly doped SPSed SiC ceramics at temperatures of 1700°C–1800°C with no applied load . Moreover, Herrmann et al .…”

Section: Introductionmentioning

confidence: 99%

Effects of Current Confinement on the Spark Plasma Sintering of Silicon Carbide Ceramics

et al. 2015

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Despite numerous works have recently reported the densification of silicon carbide (SiC) ceramics using the Spark Plasma Sintering (SPS) technique, the effect of the localized electric current flow near the specimen over the liquid phase sintering process of SiC ceramics and on their microstructural features has not been completely addressed. In the present work, two different SPS setups affecting current flow are selected, one based on the ordinary die/punch setup configuration, and the other employing a BN electrically insulating coating on the inner wall of the die to force the electric current to locally flow through the inner graphite foil in contact with the ceramic compact. The effective electrical resistance and the energy consumed during the SPS runs for both setups, as well as the sintering behavior, microstructure, and mechanical properties of the SPSed materials are analyzed. The BN die coating considerably increases the effective resistance of the system, decreases the power consumption, and accelerates the SiC densification. Besides, ceramic specimens experience significantly higher real temperatures than the set values and, accordingly, coarser microstructures and tougher materials than those for the ordinary setting are produced. The thermoelectrical properties of SiC materials are proposed as fundamental in their SPS process, especially when electrical current is forced through the inner part of the SPS setting around the specimen.

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“…A detailed description of SiC scaffolds fabrication by the robocasting method can be found in [15,16]. In brief, a colloidal gel ink, based on SiC powder, is extruded * corresponding author; e-mail: martin.koller@fjfi.cvut.cz through a nozzle in an oil bath, following a layer-bylayer printing route defined by CAD.…”

Section: Methodsmentioning

confidence: 99%

“…Robocasting is an additive manufacturing technique in which the microscaffolds consisting of thin rods are fabricated from a powder slurry [15,16]. In this paper, robocast silicon carbide (SiC) samples were used as templates for the finite element method (FEM) modeling of elastic and acoustic properties of such microarchitectured scaffolds.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Elasticity of Ceramic Micro-Scaffolds Fabricated by Robocasting

et al. 2018

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Anisotropic elastic and acoustic properties of robocast ceramic scaffolds are calculated by finite element method, utilizing real geometries and material parameters obtained from robocast silicon carbide samples. Six types of robocast geometries are studied, showing different material symmetries given by the arrangement of the ceramic rods in the scaffold structures. Due to the macroscopic periodicity of the structures composed of fully sintered ceramic rods, the robocast scaffolds exhibit metamaterial-like elastic and acoustic properties, never observed for natural materials. The effect of the micro-architecture is shown to be crucial: while for tetragonal and orthorhombic structures, strong acoustic focusing along the directions of the rods appears even in the low-frequency limit, hexagonal structures exhibit no energy focusing up to some frequency limit given by the geometry.

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Microstructural designs of spark-plasma sintered silicon carbide ceramic scaffolds

Cited by 21 publications

References 20 publications

Ultrasonic bandgaps in 3D-printed periodic ceramic microlattices

Ultrasonic bandgaps in 3D-printed periodic ceramic microlattices

Effects of Current Confinement on the Spark Plasma Sintering of Silicon Carbide Ceramics

Anisotropic Elasticity of Ceramic Micro-Scaffolds Fabricated by Robocasting

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