Ingenieurwissenschaften und zugeordnete Tätigkeiten
Filtern
Dokumenttyp
- Zeitschriftenartikel (43)
- Vortrag (38)
- Posterpräsentation (19)
- Beitrag zu einem Tagungsband (1)
- Sonstiges (1)
Schlagworte
- Glass (29)
- Crystallization (14)
- Crack growth (12)
- Sintering (11)
- DCB (9)
- Water speciation (9)
- Soda-lime silicate glass (7)
- Vickers (7)
- Water content (7)
- EBSD (5)
- Foaming (5)
- Bildanalyse (4)
- Bioactive glass (4)
- Internal friction (4)
- Ontologie (4)
- Orientation (4)
- Oxidglas (4)
- Corrosion (3)
- Crystal orientation (3)
- Digitaler Zwilling (3)
- Diopside (3)
- Fracture Toughness (3)
- Glas (3)
- Glass ceramic (3)
- Glass powder (3)
- ML (3)
- NMR spectroscopy (3)
- Oxide Glasses (3)
- Silicate Glasses (3)
- Surface crystallization (3)
- Surface energy (3)
- Vickers indentation (3)
- Wasser (3)
- Al2O3 (2)
- Alkali zinc borate glasses (2)
- Bioactive Glass (2)
- Bond energy (2)
- Coating (2)
- Diffusion coefficient (2)
- Diopsid (2)
- Elastic constants (2)
- Fracture surface energy (2)
- Geothermal (2)
- GlasDigital (2)
- Glass composition (2)
- Glass transition (2)
- Glass-ceramic (2)
- IR (2)
- Infrared spectroscopy (2)
- Lead borate glasses (2)
- Martensitic steel (2)
- Material Digital (2)
- Mechanical properties (2)
- Microhardness (2)
- Powder (2)
- Relaxation (2)
- Risswachstum (2)
- Robotische Glasschmelzanlage (2)
- Soda-lime-silica glass (2)
- Sol-gel coating (2)
- Stress intensity factor (2)
- Superconducting magnet (2)
- Surface (2)
- Surface Energy (2)
- Viscosity (2)
- robotische Glasschmelzanlage (2)
- 3D REM (1)
- 3D etching (1)
- 3D glass structure model (1)
- 3D printing (1)
- Acid-leaching (1)
- Alkali aluminosilicate glasses (1)
- Alkali and alkaline earth silicate and borate glass (1)
- Aluminosilicate glasses (1)
- Analytical scanning electron microscopy (1)
- Artificial weathering (1)
- Atomic packing factor (1)
- Automated analysis (1)
- BCS (1)
- BTS (1)
- Behmite (1)
- Blähen (1)
- Borosilicate glass (1)
- Brittle fracture (1)
- Bruchflächen (1)
- Bubble formation (1)
- Calculated intrinsic fracture toughness (1)
- Ceramic multilayers (1)
- Co-firings (1)
- Coefficient of thermal expansion (1)
- Crack growth in air (1)
- Crack healing (1)
- Crosslinking (1)
- Crystal growth (1)
- Crystal growth velocity (1)
- Crystal lattice (1)
- Crystal morphology (1)
- Cytocompatibility (1)
- DCB geometry (1)
- Data space (1)
- Degradation (1)
- Density (1)
- Differential scanning calorimetry (1)
- Diffusion (1)
- Digitalisierung (1)
- Dissolved water (1)
- Dynamic mechanical analysis (1)
- Dynamisch Mechanische Analyse (1)
- Exposed metal sites (1)
- Facilitated activation (1)
- Ferrous phosphate hydrate (1)
- Formerkennung (1)
- Fracture Mechanics (1)
- Fracture surface (1)
- Fracture toughness (1)
- Fragility (1)
- Fraktographie (1)
- Fresnoit (1)
- Fresnoite (1)
- Gasabgabe (1)
- Gasgehalt (1)
- General Chemistry (1)
- Glass Ceramic (1)
- Glass crystallization stress (1)
- Glass melting (1)
- Glass screening device (1)
- Glass transformation temperature (1)
- Glass-ceramics definition (1)
- Growth kinetics (1)
- Growth rate (1)
- High pressure (1)
- High temperature (1)
- High-temperature oxidation (1)
- Hochtemperatur (1)
- Hydrogen diffusivity (1)
- Hydrogen permeability (1)
- Hydrogen permeation (1)
- Hydrous glass (1)
- IR spectroscopy (1)
- Inconel 625 (1)
- Indentation fracture toughness (1)
- Internal stresses (1)
- Ion beam erosion Sectioning (1)
- Ionic porosity (1)
- JMAK model (1)
- Kristallisation (1)
- Low expansion (1)
- MOF-74 (1)
- Martensitic steels (1)
- Materials Chemistry (1)
- Mechanical Engineering (1)
- Mechanics of Materials (1)
- Metals and Alloys (1)
- Microstructure (1)
- Milling (1)
- Mixed-linkers (1)
- Modeling (1)
- Moisture (1)
- NMR (1)
- Nb3Sn (1)
- Non-desired foaming (1)
- Nucleation (1)
- Nucleation mode (1)
- Nucleation tendency (1)
- Nydrogen melting (1)
- Ontology (1)
- Oriented surface crystallization (1)
- Oxidation protection (1)
- Oxide glass (1)
- Peem (1)
- Phase Separation (1)
- Phase transformations (1)
- Phosphate (1)
- Physical properties (1)
- Polymer (1)
- Polyurethane (1)
- Property simulation (1)
- Protective coating (1)
- Raman spectroscopy (1)
- Relaxationsphänomene (1)
- Resonance testing (1)
- Robot-assisted galss melting (1)
- Roboter (1)
- SEM (1)
- Sample preparation (1)
- Scaffolds (1)
- Shear thinning (1)
- Silicate glass (1)
- Silicatglas (1)
- Silicoborate glasses (1)
- Simulation (1)
- Sinter retardation (1)
- Sintern (1)
- Sinterung (1)
- Slow crack growth (1)
- Soda lime silicate glass (1)
- Soda-lime-silica (1)
- Sodium ion batteries (1)
- Sodiumborosilicate glasses (1)
- Solubility (1)
- Stable crack growth (1)
- Stress intensity (1)
- Stress-corrosion (1)
- Stress-strain behavior (1)
- Stress-strain-behavior (1)
- Structural defects (1)
- Struktur (1)
- Subcritical crack growth (1)
- Supersaturation (1)
- Surface Nucleation (1)
- Surface nucleation (1)
- Surface roughness (1)
- Synchrotron (1)
- Synchrotron micro-tomography (1)
- Thermal expansion (1)
- Thermo-optical measurement (1)
- Thermoanalytical Methods (1)
- Toughness (1)
- Vacuum hot extraction (1)
- Viscous sintering (1)
- Vivianite (1)
- Volume changes (1)
- Water (1)
- Water in glass (1)
- X-ray diffraction (1)
- XRM (1)
- Young`s modulus (1)
- Young´s modulus (1)
- Young’s Modulus (1)
- high pressure (1)
- infrared spectroscopy (1)
- phosphate glasses (1)
- water speciation (1)
Organisationseinheit der BAM
- 5.6 Glas (102) (entfernen)
Eingeladener Vortrag
- nein (38)
This study investigates the sintering and crystallization behavior and kinetic of the bioactive glass (BG) 13–93 with nominal composition (in mol%): 54.6 SiO2 - 1.7 P2O3 - 22.1 CaO - 6.0 Na2O - 7.9 K2O - 7.7 MgO. Sintering and crystallization were investigated non-isothermally for various particle size fractions smaller than 315 μm as well as for bulk samples. Densification was not hindered by the presence of crystalline phases across all particle size fractions. Afterwards, wollastonite was found as the dominant crystal phase at higher temperature which resorb primary surface precipitation-like quartz crystallites. The growth direction shifts into volume when the sample surface is nearly covered. The crystal growth rate of wollastonite was calculated from the crystalline surface layer thickness measured during heating. The findings of this study are relevant for the high temperature processing of BG 13–93.
Processing and cytocompatibility of Cu-doped and undoped fluoride-containing bioactive glasses
(2024)
Sintered or additive-manufactured bioactive glass (BG) scaffolds are highly interesting for bone replacement applications. However, crystallization often limits the high-temperature processability of bioactive glasses (BGs). Thus, the BG composition must combine high bioactivity and processability. In this study, three BGs with nominal molar (%) compositions 54.6SiO2-1.7P2O3-22.1CaO-6.0Na2O-7.9K2O-7.7MgO (13–93), 44.8SiO2-2.5P2O3-36.5CaO-6.6Na2O-6.6K2O-3.0CaF2 (F3) and 44.8SiO2-2.5P2O3-35.5CaO-6.6Na2O-6.6K2O-3.0CaF2-1.0CuO (F3–Cu) were investigated. The dissolution and ion release kinetics were investigated on milled glass powder and crystallized particles (500–600 μm). All glasses showed the precipitation of hydroxyapatite (HAp) crystals after 7 days of immersion in simulated body fluid. No significant differences in ion release from glass and crystalline samples were detected. The influence of surface roughness on cytocompatibility and growth of preosteoblast cells (MC3T3-E1) was investigated on sintered and polished BG pellets. Results showed that sintered BG pellets were cytocompatible, and cells were seen to be well attached and spread on the surface after 5 days of incubation. The results showed an inverse relation of cell viability with the surface roughness of pellets, and cells were seen to attach and spread along the direction of scratches.
A widespread recovery of waste heat requires a cost‐effective production of thermoelectric generators. Thermoelectric oxides are predestined for use at high temperatures. For manufacturing reasons, a multilayer generator design will be easily scalable and cost‐effective. To evaluate the potential of ceramic multilayer technology for that purpose, a multilayer of the promising thermoelectric oxides calcium cobaltite (Ca3Co4O9), calcium manganate (CMO, CaMnO3), and glass–ceramic insulation layers is fabricated. Cracks and reaction layers at the interfaces are observed in the microstructure. The compositions of these reaction layers are identified by energy‐dispersive X‐ray spectroscopy and X‐ray diffraction. Mechanical and thermal properties of all layers are compiled from literature or determined by purposeful sample preparation and testing. Based on this data set, the internal stresses in the multilayer after co‐firing are calculated numerically. It is shown that tensile stresses in the range of 50 MPa occur in the CMO layers. The reaction layers have only a minor influence on the level of these residual stresses. Herein, it is proven that the material system is basically suitable for multilayer generator production, but that the co‐firing process and the layer structure must be adapted to improve densification and reduce the tensile stresses in the CMO.
The system Na2O.B2O3-SiO2 (NBS) is the basis of many industrial glass applications and therefore one of the most studied systems at all. Glass formation is possible over a wide compositional range, but the system also contains ranges of pronounced phase separation and crystallization tendency. Despite its importance, experimental data are limited to few compositional areas. The general understanding and modelling of glass formation, phase separation, and crystallization in this system would therefore be easier if small step melt series could be studied. The efficient melting of such glass series is now possible with the new robotic glass melting system at the Federal Institute for Materials Research and Testing (BAM, Division Glasses). Using three exemplary joins within this NBS system, the small step changes of glass transition temperature (Tg), crystallization behavior as well as glass density (Roh) was studied. Additionally, experimental Tg and Roh data were compared with their modeled counterparts using SciGlass and a newly developed DFT model, respectively.
AbstractViscous healing of cracks induced by the Vickers indentation in a soda lime magnesium silicate, a soda borosilicate, and a soda aluminosilicate glass (NAS) was studied by laser scanning microscopy. Plots of the crack length, width, and depth normalized to the initial crack length versus time over viscosity merge into single master curves of each of these quantities for each glass. Despite glass properties do not differ strikingly from each other, however, these master curves strongly differ among the glasses. This finding was attributed to a different interplay of various crack healing phenomena. Lateral cracks were found to be responsible for the bulging of the sample surface around the Vickers imprint, which in turn promotes radial crack widening as the main cause of healing delay. The most rapid healing of lateral cracks was observed in NAS in which bulging and crack widening were least pronounced.
Silicate glass fracture surface energy calculated from crystal structure and bond-energy data
(2023)
We present a novel method to predict the fracture surface energy, γ, of isochemically crystallizing silicate glasses using readily available crystallographic structure data of their crystalline counterpart and tabled diatomic chemical bond energies, D0. The method assumes that γ equals the fracture surface energy of the most likely cleavage plane of the crystal. Calculated values were in excellent agreement with those calculated from glass density, network connectivity and D0 data in earlier work. This finding demonstrates a remarkable equivalence between crystal cleavage planes and glass fracture surfaces.
Controlled oriented crystallization of glass surfaces is desired for high precision applications, since the uppermost crystal layer significantly influences the properties of the material. In contrast to previous studies, the data presented here deal with separated crystals growing at defect-free surfaces in four atmospheres with different degrees of humidity (ambient/dry air, argon and vacuum). A glass with the composition 2 BaO–TiO2–2.75 SiO2 was heat-treated at 825 °C until fresnoite (Ba2TiSi2O8) grew to a significant size. The crystal growth rate is found to increase with increasing humidity. The morphology of the crystals changes from highly distorted dendrites in the driest atmosphere (vacuum) to circular/spear-head-shaped crystals in the wettest atmosphere (ambient air), which we attribute to a decrease in viscosity of the glass surface due to water uptake. The least distorted crystals appear in the form of depressions of up to 6 µm. This has an influence on the observed crystal orientation, as measured by electron backscatter diffraction (EBSD). The pulled-in crystals change the orientation during growth relative to the flat glass surface due to an enrichment in SiO2 at the crystal fronts. This confirms that the orientation of crystals is not fixed following nucleation.
GlasDigital
(2023)
Der aktuelle Stand des MateriaDigital1 Projektes GlasDigital wird vorgestellt. Hierbei wird allgemein die Problem- und Zielstellung präsentiert, als auch auf 2 separaten Postern die Ergebnisse. Diese beinhalten zum Einen die smarte Gestaltung der robotergestützten Glasschmelzanlage der BAM inkl. Analytik und zum Anderen die Digitalisierungsbestrebungen im Bereich Glas, d.h. ML-gestützte C-S-P-Simulation, Ontologie für den Werkstoff Glas, Digitaler Zwilling des Gießprozesses.
GlasDigital
(2023)