Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (80) (entfernen)
Sprache
- Englisch (80) (entfernen)
Schlagworte
- Additive manufacturing (17)
- Additive Manufacturing (13)
- 3D printing (6)
- Ceramics (6)
- Bone regeneration (4)
- Ceramic (4)
- Computed tomography (4)
- Microstructure (4)
- Porosity (4)
- 3D-Printing (3)
- 3D-printing (3)
- Glass-ceramic (3)
- Sintering (3)
- Additive Fertigung (2)
- Binder Jetting (2)
- Binder jetting (2)
- Bioactive glass (2)
- Bioactivity (2)
- Bioceramics (2)
- Flowability (2)
- Glass microspheres (2)
- KNN (2)
- Keramik (2)
- Large animal model (2)
- Large animal model sheep (2)
- Laser (2)
- Layerwise slurry deposition (2)
- Lunar regolith (2)
- Mars (2)
- Mechanical properties (2)
- Osteoporotic vertebral fracture (2)
- Printing (2)
- Scaffold (2)
- Si3N4 (2)
- Silicon carbide (2)
- Silicon nitride (2)
- Space (2)
- Strength (2)
- Vertebroplasty (2)
- 2PP (1)
- 3-D printing (1)
- 3D (1)
- ATZ (1)
- Additive manufacturing, 3D printing (1)
- Al2O3 reaction bonding (1)
- Al2O3-Y2O3-ZrO2 (1)
- Alcium alkali phosphate (1)
- Alkali-activated materials (1)
- Alpha-tricalcium phosphate (1)
- Alumina toughened zirconia (1)
- Anisotropic grain growth (1)
- Bacteria (1)
- Binders/binding (1)
- Bio Ceramic (1)
- Bio Ceramics (1)
- Bio active ceramic (1)
- Bioactive bone grafting material (1)
- Bioactive glass scaffold (1)
- Biphasic calcium phosphate (1)
- Bone marrow extrusion (1)
- Bone marrow-derived mesenchymal stem cell (1)
- Bone tissue engineering (1)
- Brushite-forming calcium phosphate cement (1)
- Calcium alkali orthophosphate (1)
- Calcium alkali orthophosphate materials (1)
- Calcium alkaline orthophosphates (1)
- Calcium alkaline phosphates (1)
- Calcium phosphat cement (1)
- Calcium phosphate cement (1)
- Cell culture media (1)
- Cellular (1)
- Cement injection (1)
- Cement-based materials (1)
- Ceramic nano particles (1)
- Characterisation (1)
- Clay ISRU (1)
- Compressive strength (1)
- Crystallization (1)
- Crystallization behavior (1)
- Cuttlefish (1)
- D. ZrO2 (1)
- Debinding (1)
- Defect detection (1)
- Dense alumina (1)
- Drywood termite (1)
- Efficiency (1)
- Emissivity (1)
- Endothelial progenitor cell (1)
- Environment (1)
- Eutectic ceramics (1)
- Ex vivo (1)
- Fatigue (1)
- Fetal bovine serum (1)
- Firing (1)
- Fungi (1)
- Gas flow assisted powder deposition (1)
- Glass ceramics (1)
- Graded (1)
- Grain boundary (1)
- Hausner ratio (1)
- High- viscosity PMMA cement (1)
- Hot stage microscopy (1)
- Hybrid Manufacturing (1)
- ISRU (1)
- Image-based analysis (1)
- In vivo (1)
- In-situ Process Monitoring (1)
- In-vivo (1)
- Infrared optical properties (1)
- Inkjet (1)
- LAS (1)
- LIBS (1)
- LSD print (1)
- Laser beam melting (1)
- Laser processing (1)
- Laser-induced slip casting (1)
- Laserwise-slurry-deposition (LSD) (1)
- Lattices (1)
- Layer-wise slurry deposition (1)
- Layerwise Slurry Deposition (1)
- MGS-1 regolith simulant (1)
- Mandible (1)
- Manufacturing (1)
- Materials science (1)
- Mean pore diameter (1)
- Melting (1)
- Meta material (1)
- Metallic Glass (1)
- Micro-scale bone scaffolds (1)
- Minimal-invasive (1)
- Mixed Ca-K-Na phosphates (1)
- Moon (1)
- Multiresolution modeling (1)
- Multiscale FEA (1)
- Na and K rhenanites (1)
- Nano-ceramic-additive-manufacturing photoresin (1)
- Nano-powder (1)
- NanoCAM (1)
- Nanopowder (1)
- Networking (1)
- Non-destructive Materials (1)
- Osteogenesis (1)
- Oxide ceramic (1)
- PLGA cement (1)
- PV modules (1)
- Parabolic flight (1)
- Particle size (1)
- Particle size gradation (1)
- Phase diagram (1)
- Phase transformations (1)
- Phototrophs (1)
- Photovoltaic modules (1)
- Plasma imaging (1)
- Plasticity (1)
- Polymer (1)
- Polymeric Materials (1)
- Porcelain (1)
- Porous ceramics (1)
- Powder bed (1)
- Powder bed additive manufacturing (1)
- Powder bed density (1)
- Powder flow (1)
- Powder processing (1)
- Powder rheology (1)
- Powder-based processes (1)
- Preceramic polymer (1)
- Preceramic polymers (1)
- Process (1)
- Process development (1)
- Processing window (1)
- Quality assurance (1)
- Rapid nitridation (1)
- Rapid prototyping (1)
- Reaction Sintering (1)
- Reaction bonding (1)
- Real-time deformation (1)
- Real-time qPCR (1)
- Regolith (1)
- Roughness (1)
- SEM micrography (1)
- Safety (1)
- Sand blasting (1)
- Scaffold geometry (1)
- SchwarzP cells (1)
- Selective laser sintering (1)
- Selective laser sintering (SLS) (1)
- Self-Assembly (1)
- Self-organization (1)
- Shadowgraphy (1)
- Shaping (1)
- Sheep (1)
- Si3N4/SiC porous ceramics (1)
- SiO2 (1)
- Silicate glass-ceramics (1)
- Silicon Carbide (1)
- Silicon release (1)
- Sinus floor augmentation (1)
- Slurry (1)
- Smectite (1)
- Softening temperature (1)
- Solar panels (1)
- Standardisation (1)
- Stressed (1)
- Three-dimensional Bone tissue engineering (1)
- Three-dimensional printing (1)
- Trabecular structures (1)
- Transmittance (1)
- Transparency (1)
- Transparent ceramic (1)
- Tricalcium Phosphate (1)
- Triply Periodical Minimal Surface (1)
- Two-photon polymerization (1)
- Two-photon-polymerization (1)
- Unstressed (1)
- Vertebral (1)
- Viscous sintering (1)
- Void defect (1)
- Wetting (1)
- X-ray refraction (1)
- X-ray tomographic (1)
- Yttria stabilized zirconia (1)
- Zirconia: yttria stabilized (1)
- ZnO (1)
- µ-gravity (1)
- µCT (1)
Organisationseinheit der BAM
- 5 Werkstofftechnik (43)
- 5.4 Multimateriale Fertigungsprozesse (43)
- 8 Zerstörungsfreie Prüfung (6)
- 6 Materialchemie (5)
- 8.5 Röntgenbildgebung (4)
- 4 Material und Umwelt (3)
- 7 Bauwerkssicherheit (3)
- 7.4 Baustofftechnologie (3)
- 4.0 Abteilungsleitung und andere (2)
- 5.1 Mikrostruktur Design und Degradation (2)
Paper des Monats
- ja (3)
Recently, efforts towards the development of patient-specific 3D printed scaffolds for bone tissue engineering from bioactive ceramics have continuously intensified. For reconstruction of segmental defects after subtotal mandibulectomy a suitable tissue engineered bioceramic bone graft needs to be endowed with homogenously distributed osteoblasts in order to mimic the advantageous features of vascularized autologous fibula grafts, which represent the standard of care, contain osteogenic cells and are transplanted with the respective blood vessel. Consequently, inducing vascularization early on is pivotal for bone tissue engineering. The current study explored an advanced bone tissue engineering approach combining an advanced 3D printing technique for bioactive resorbable ceramic scaffolds with a perfusion cell culture technique for pre-colonization with mesenchymal stem cells, and with an intrinsic angiogenesis technique for regenerating critical size, segmental discontinuity defects in vivo applying a rat model. To this end, the effect of differing Si-CAOP (silica containing calcium alkali orthophosphate) scaffold microarchitecture arising from 3D powder bed printing (RP) or the Schwarzwalder Somers (SSM) replica fabrication technique on vascularization and bone regeneration was analyzed in vivo. In 80 rats 6-mm segmental discontinuity defects were created in the left femur.
Future lunar exploration will be based on in-situ resource utilization (ISRU) techniques. The most abundant raw material on the Moon is lunar regolith, which, however, is very scarce on Earth, making the study of simulants a necessity. The objective of this study is to characterize and investigate the sintering behavior of EAC-1A lunar regolith simulant. The characterization of the simulant included the determination of the phase assemblage, characteristic temperatures determination and water content analysis. The results are discussed in the context of sintering experiments of EAC-1A simulant, which showed that the material can be sintered to a relative density close to 90%, but only within a very narrow range of temperatures (20–30 °C). Sintering experiments were performed for sieved and unsieved, as well as for dried and non-dried specimens of EAC-1A. In addition, an analysis of the densification and mechanical properties of the sintered specimens was done. The sintering experiments at different temperatures showed that the finest fraction of sieved simulant can reach a higher maximum sintering temperature, and consequently a higher densification and biaxial strength. The non-dried powder exhibited higher densification and biaxial strength after sintering compared to the dried specimen. This difference was explained with a higher green density of the non-dried powder during pressing, rather than due to an actual influence on the sintering mechanism. Nevertheless, drying the powder prior to sintering is important to avoid the overestimation of the strength of specimens to be fabricated on the Moon.
(1) Background: The desire to avoid autograft harvesting in implant dentistry has prompted an ever-increasing quest for bioceramic bone substitutes, which stimulate osteogenesis while resorbing in a timely fashion. Consequently, a highly bioactive silicon containing calcium alkali orthophosphate (Si-CAP) material was created, which previously was shown to induce greater bone cell maturation and bone neo-formation than β-tricalcium phosphate (β-TCP) in vivo as well as in vitro. Our study tested the hypothesis that the enhanced effect on bone cell function in vitro and in sheep in vivo would lead to more copious bone neoformation in patients following sinus floor augmentation (SFA) employing Si-CAP when compared to β-TCP. (2) Methods: The effects of Si-CAP on osteogenesis and Si-CAP resorbability were evaluated in biopsies harvested from 38 patients six months after SFA in comparison to β-TCP employing undecalcified histology, histomorphometry, and immunohistochemical analysis of osteogenic marker expression. (3) Results: Si-CAP as well as β-TCP supported matrix mineralization and bone formation. Apically furthest away from the original bone tissue, Si-CAP induced significantly higher bone formation, bone-bonding (bone-bioceramic contact), and granule resorption than β-TCP. This was in conjunction with a higher expression of osteogenic markers. (4) Conclusions: Si-CAP induced higher and more advanced bone formation and resorbability than β-TCP, while β-TCP’s remarkable osteoconductivity has been widely demonstrated. Hence, Si-CAP constitutes a well-suited bioactive graft choice for SFA in the clinical arena.
The microstructure of an apatite-wollastonite (code name AP40) glass-ceramic is analyzed in this study by combining 2D microscopy, phase analysis, X-ray absorption and synchrotron X-ray refraction computed tomography (XCT and SXRCT, respectively). It is shown that this combination provides a useful toolbox to characterize the global microstructure in a wide scale range, from sub-micrometer to millimeter. The material displays a complex microstructure comprising a glassy matrix with embedded fluorapatite and wollastonite small crystals. In this matrix, large (up to 200 μm) spike-shaped structures are distributed. Such microstructural features are oriented around a central sphere, thereby forming a structure resembling a sea urchin. A unique feature of SXRCT, in contrast to XCT, is that internal interfaces are visualized; this allows one to show the 3D distribution of these urchins with exceptionally good contrast. Furthermore, it is revealed that the spike-shaped structures are not single crystals, but rather composed of sub-micrometric crystals, which are identified as fluorapatite and diopside phases by SEM-EDX analysis.
Additive manufacturing of metals – and in particular building with laser-based powder bed fusion – is highly flexible and allows high-resolution features and feedstock savings. Meanwhile, though space stations in low Earth orbit are established, a set of visits to the Moon have been performed, and humankind can send out rovers to explore Venus and Mars, none of these milestone missions is equipped with technology to manufacture functional metallic parts or tools in space. In order to advance space exploration to long-term missions beyond low Earth orbit, it will be crucial to develop and employ technology for in-space manufacturing (ISM) and in-situ resource utilisation (ISRU). To use the advantages of laser-based powder bed fusion in these endeavours, the challenge of powder handling in microgravity must be met. Here we present a device capable of building parts using metallic powders in microgravity. This was proven on several sounding rocket flights, on which occasions Zr-based metallic glass parts produced by additive manufacturing in space were built. The findings of this work demonstrate that building parts using powder feedstock, which is more compact to transport into space than wire, is possible in microgravity environments. This thus significantly advances ISRU and ISM and paves the way for future tests in prolonged microgravity settings.
Filigree structures can be manufactured via two-photon-polymerization (2PP) operating in the regime of non-linear light absorption. For the first time it is possible to apply this technique to the powder processing of ceramic structures with a feature size in the range of the critical defect size responsible for brittle fracture and, thus, affecting fracture toughness of high-performance ceramics. In this way, tailoring of advanced properties can be achieved already in the shaping process. Traditionally, 2PP relies on transparent polymerizable resins, which is diametrically opposed to the usually completely opaque ceramic resins and slurries. Here we present a transparent and photocurable suspension of nanoparticles (resin) with very high mass fractions of yttria-stabilized zirconia particles (YSZ). Due to the extremely well dispersed nanoparticles, scattering of light can be effectively suppressed at the process-relevant wavelength of 800 nm. Sintered ceramic structures with a resolution of down to 500 nm were obtained. Even at reduced densities of 1 to 4 g/cm³, the resulting compressive strength with 4,5 GPa is equivalent or even exceeding bulk monolithic yttria stabilized zirconia. A ceramic metamaterial is born, where the mechanical properties of yttria stabilized zirconia are altered by changing geometrical parameters and gives access to a new class of ceramic materials.
Methods and materials are presented here, which enable the manufacturing of fine structures using a 3D-printing method known as two-photon polymerization (2PP). As traditional photolithography methods for structuring ceramic slurries do not function with 2PP, due to light scattering on ceramic particles, a novel water-based photoresist with high ceramic loading of extremely well dispersed ceramic nano particles was developed. This photoresist is basically a ceramic slurry containing a photocurable agent and a photoinitiator to be crosslinkable with the 780 nm wavelength femtosecond laser light source of the 2PP machine. It is demonstrated that it is possible to gain a highly transparent and low viscous slurry suitable for 2PP processing. This work shows the development of the slurry, first printing results and the post-printing processes required to form three dimensional ceramic microstructures consisting of alumina toughened zirconia (ATZ).
As humanity contemplates manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments to safely work in space for years. The supply of spare parts for repair and replacement of lost equipment will be one key need, but in-space manufacturing remains the only option for a timely supply. With high flexibility in design and the ability to manufacture ready-to-use components directly from a computeraided model, additive manufacturing (AM) technologies appear extremely attractive. For the manufacturing of metal parts, laser-beam melting is the most widely used AM process. However, the handling of metal powders in the absence of gravity is one prerequisite for its successful application in space. A gas flow throughout the powder bed is successfully applied to compensate for missing gravitational forces in microgravity experiments. This so-called gas-flow-assisted powder deposition is based on a porous Building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump.
AbstractTwo‐photon polymerization (2PP) additive manufacturing (AM) utilizes feedstocks of ceramic nanoparticles of a few nanometers in diameter, enabling the fabrication of highly accurate technical ceramic design with structural details as small as 500 nm. The performance of these materials is expected to differ from conventional AM ceramics, as nanoparticles and three‐dimensional printing at high resolution introduce new microstructural aspects. This study applies 2PP‐AM of yttria‐stabilized zirconia to investigate the mechanical response behavior under compressive load, probing the influence of smallest structural units induced by the line packing during the printing process, design of sintered microblocks, and sintering temperature and thereby microstructure. We find a dissipative mechanical response enhanced by sintering at lower temperatures than conventional. The pursued 2PP‐AM approach yields a microstructured material with an increased number of grain boundaries that proposedly play a major role in facilitating energy dissipation within the here printed ceramic material. This microplastic response is further triggered by the filigree structures induced by hollow line packing at the order of the critical defect size of ceramics. Together, these unique aspects made accessible by the 2PP‐AM approach contribute to a heterogeneous nano‐ and microstructure, and hint toward opportunities for tailoring the mechanical response in future ceramic applications.