Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (22)
- Beitrag zu einem Tagungsband (15)
- Beitrag zu einem Sammelband (11)
- Vortrag (8)
- Posterpräsentation (7)
- Sonstiges (1)
- Forschungsbericht (1)
Schlagworte
- Computed tomography (12)
- Computertomographie (6)
- Computer Tomographie (3)
- Fire resistance (3)
- Intumescence (3)
- Osteoporotic vertebral fracture (3)
- Simulation (3)
- X-ray refraction (3)
- Aerospace (2)
- Bone regeneration (2)
- CT (2)
- Cast plaster statues (2)
- Computed Tomography (CT) (2)
- Diffraction Enhanced Imaging (DEI) (2)
- In-situ Druckversuch (2)
- Large animal model (2)
- Large animal model sheep (2)
- MMC (2)
- Metal Matrix Composites (MMC) (2)
- Micro-CT (2)
- NDE (2)
- Oberfläche (2)
- Oberflächenbestimmung (2)
- Sheep (2)
- Vertebroplasty (2)
- Zerstörungsfreie Bodenproben (2)
- µCT (2)
- 3D (1)
- 3D-micro-CT (1)
- Artifacts (1)
- Bench scale fire testing (1)
- Bench-scale fire test (1)
- Bench‐scale fire testing (1)
- Bioerosion (1)
- Bodenstruktur (1)
- Bone marrow extrusion (1)
- Bone morphogenetic protein; (1)
- Bone regeneration; (1)
- Bragg Magnification (1)
- Bragg magnification (1)
- Bragg-Magnification (1)
- Brushite-forming calcium phosphate cement (1)
- Calcium phosphat cement (1)
- Calcium phosphate bone cement (1)
- Calcium phosphate cement (1)
- Calcium phosphate cement; (1)
- Carbonate substrate (1)
- Carrara marble sculpture (1)
- Cement injection (1)
- Characterization (1)
- Coating (1)
- Complex microstructure (1)
- Composites (1)
- Compressive strength (1)
- Computed Tomography (1)
- Computed X ray tomography (1)
- Computed microtomography (1)
- Computerized tomography (1)
- Condition assessment (1)
- Conservation (1)
- Correlation (1)
- Epoxy resin (1)
- Ex vivo (1)
- Fire protective coating (1)
- Fire residue (1)
- Flame retardancy (1)
- GDF-5 mutant; (1)
- Grassland sites (1)
- High- viscosity PMMA cement (1)
- Hochspannungsüberschlag (1)
- Image processing (computer-assisted) (1)
- Implants (1)
- In vivo (1)
- In-situ compression (1)
- Internal structure (1)
- Internal structures (1)
- Large animal model sheep; (1)
- Lightweight Materials (1)
- Lightweight materials (1)
- Material flaws (1)
- Melamine poly(metal phosphate) (1)
- Micro-Computed-Tomography; (1)
- Micro-computed tomography (1)
- Minimal-invasive (1)
- Minimally-invasive parapatellar approach (1)
- Mobile CT (1)
- Mobile RFA (1)
- Morphology analysis (1)
- Non-Destructive Inspection (NDI) (1)
- Nuclear magnetic resonance (1)
- Oil-based (1)
- Ortsauflösung (1)
- Osteochondral stifle joint defect (1)
- Osteoporosis (1)
- PLGA cement (1)
- PMMA (1)
- Plant roots (1)
- Pore size (1)
- Porous concrete (1)
- Quantitative image analysis (1)
- Ready-to-use (1)
- Refraction (1)
- Residue analysis (1)
- Restoration (1)
- Röhrenvergleich (1)
- SCS6 (1)
- Sheep animal model (1)
- Soil science (1)
- Soil structure (1)
- Solid-state NMR (1)
- Standard time temperature furnace (1)
- Statistical analysis (1)
- Synchrotron Radiation (1)
- Synchrotron Refraction CT (1)
- Synchrotron radiation (1)
- Three dimensional microtomography (1)
- Ti-MMC (1)
- Ti6242 (1)
- Titanium Metal Matrix Composites (Ti-MMC) (1)
- Ultrasound computed tomography (1)
- Validation (1)
- Vertebral (1)
- Visualization (1)
- Void defect (1)
- Water-based (1)
- X-ray Refraction (1)
- X-ray absorption and refraction CT (1)
- X-ray micro-CT (1)
- Young’s modulus (1)
- aluminum (1)
- computed tomography (1)
- flash thermography (1)
- pores (1)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (8)
Revealing the inner secrets of intumescent chars by advanced small scale tests combined with µ-CT
(2015)
Testing of intumescent coatings for Steel is usually done in intermediate scale or even full scale experiments and is hence quite expensive. We developed two complementary small scale tests, simulating fully developed Tire. First is a strongly modified electrical muffle furnace, which is now able to follow the Standard temperature-time curve (according EN 1363-1) for 90 min in a very accurate manner. Düring the experiment backside temperatures are recorded and the growth of the char is observed with a custom made high temperature endoscope. Second is a testing apparatus based on a propane-oxygen-bumer for direct severe flame impingement of coated samples, reaching temperatures far above 1500 °C.
Our small scale samples are coated Steel plates of a size of 75 x 75 x 2 mm3. The structure-propertyrelation between additives, thermal properties and morphology of the char were examined using a well determined series of samples consisting of basic composition mixed with different additives. With the burner-testing-apparatus we studied the behavior of a high performance coating, which shows a transformation of the carbonaceous char into a ceramic foam at temperatures as high as 1600 °C. Nondestructive micro-computed tomography was used to characterize the morphology of the char. According to the structure of the foams we used different analytic methods like cell-detection or wallthickness-analysis. Additional scanning electron and optical microscopy were performed. The combination of the CT-data with the measured backside temperatures of the different samples provides us a deep understanding of the interaction between isolating properties and morphology of intumescent chars.
Intumescent coatings have been used for fire protection of steel for decades, but there is still a need for improvement and adaptation. The key parameters of such coatings in a fire Scenario are thermal insulation, foaming dynamics, and cohesion. The fire resistance tests, large furnaces applying the standard time temperature (STT) curve, demand coated full‐scale components or intermediate‐scale specimen. The STT Mufu+ (standard time temperature muffle furnace+) approach is presented. It is a recently developed bench‐scale testing method to analyze the performance of intumescent coatings. The STT Mufu+ provides vertical testing of specimens with reduced specimen size according to the STT curve. During the experiment, the foaming process is observed with a high‐temperature endoscope. Characteristics of this technique like reproducibility and resolution are presented and discussed. The STT Mufu+ test is highly efficient in comparison to common tests because of the reduced sample size. Its potential is extended to a superior research tool by combining it with advanced residue analysis (μ‐computed tomography and scanning electron microscopy) and mechanical testing. The benefits of this combination are demonstrated by a case study on 4 intumescent coatings. The evaluation of all collected data is used to create performance‐based rankings of the tested coatings.
In addition to the acid source, charring agent, and blowing agent, the binder is a crucial part of an intumescent coating. Its primary task is to bind all compounds, but it also acts as a carbon source and influences the foaming process. A series of intumescent coatings based on five different binders was investigated in terms of insulation, foaming, mechanical impact resistance, and residue morphology. The Standard Time-Temperature modified Muffle Furnace (STT MuFu+ ) was used for the bench-scale fire resistance tests and provided data on temperature and residue thickness as well as well-defined residues. The residue morphology was analyzed by nondestructive m-computed tomography and scanning electron microscopy. A moderate influence of the binder on insulation performance was detected in the set of coatings investigated, whereas the foaming dynamics and thickness achieved were affected strongly. In addition, the inner structure of the residues showed a rich variety. High expansion alone did not guarantee good insulation. Furthermore, attention was paid to the relation between the microstructure transition induced by carbon loss due to thermo-oxidation of the char and the development of the thermal conductivity and thickness of the coatings during the fire test.
Thermal insulation and mechanical resistance play a crucial role for the performance of an intumescent coating. Both properties depend strongly on the morphology and morphological development of the foamed residue. Small amounts (4 wt%) of fiberglass, clay and a copper salt, respectively, are incorporated into an intumescent coating to study their influence on the morphology and Performance of the residues. The bench scale fire tests were performed on 75 x 75 x 2 mm³ coated steel plates according to the standard time–temperature curve in the Standard Time Temperature Muffle Furnace+ (STT Mufu+). It provided information about foaming dynamics (expansion rates) and thermal insulation. Adding the copper salt halved the expansion height, whereas the clay and fiberglass Change the height of the residue only moderately. The time to reach 500 °C was improved by 31% for clay and 15% for the other two fillers. Nondestructive micro computed tomography is used to assess the inner structure of the residues. A transition of the residue from a black, carbonaceous foam with closed cells into an inorganic, residual open cell sponge occurs at high temperatures. This transition is due to a loss of carbon; the change in microstructure is analyzed by scanning electron microscopy. Additional mechanical tests are performed and interpreted with respect to the results of the morphology analysis. Adding clay or copper salt improved the mechanical resistance tested by a factor 4. The additives significantly influence the thickness and foaming Dynamics as well as the inner structure of the residues, whereas their influence on insulation Performance is moderate. In conclusion, different modes of action are observed to achieve similar insulation performance during the fire test.
Synergistic multicomponent systems containing melamine poly(metal phosphate)s have been recently proposed as flame retardants. This work focuses on the decomposition pathways, molecular mechanisms and morphology of the fire residues of epoxy resin (EP) flame retarded with melamine poly(zinc phosphate) (MPZnP) to explain the modes of action and synergistic effects with selected synergists (melamine polyphosphate (MPP) and AlO(OH), respectively). The total load of flame retardants was always 20 wt.%. The decomposition pathways were investigated in detail via thermogravimetric Analysis coupled with Fourier transform infrared spectroscopy. The fire residues were investigated via elemental analysis und solid-state nuclear magnetic resonance spectroscopy. The morphology of intumescent fire residues was investigated via micro-computed tomography and scanning electron microscopy.
EP + (MPZnP + MPP) formed a highly voluminous residue that showed structural features of both EP + MPZnP and EP + MPP, resulting in a highly effective protection layer. EP + (MPZnP + AlO(OH)) preserved the entire quantity of phosphorus content during combustion due to the Formation of Zn₂P₂O₇ and AlPO₄.
Drucksondierungen, teufengenaue Probenahme und Präparation MKW-kontaminierter Lockersedimente
(2000)
Erstmals wurden MMCs mit Hilfe der Interface-Kontrast verstärkenden Röntgen-Refraktions-Technik in Kombination mit der 3D-CT-Technik untersucht. Die Methode der Röntgen-Refraktions-Topography sowie der Röntgen-Refraktions-Tomography wurden in den letzten Jahren speziell für die zerstörungsfreie Charakterisierung von Leichtbau-Hochleistungs-Werkstoffen wie Verbund-Werkstoffen und Keramiken entwickelt. Die Technik basiert auf der Refraktion von Röntgenlicht an Grenzflächen zwischen Bereichen unterschiedlicher Elektronendichte wie z.B. Faser- und Matrix-Werkstoff. Auf Grund der kurzen Röntgen-Wellenlänge hat der Brechungsindex einen Wert dicht bei eins, sodass der Streuwinkel nur wenige Bogenminuten beträgt. Der Vorteil der kurzen Wellenlänge besteht jedoch darin, dass Poren und Risse detektiert werden können, deren Größe im Nanometerbereich liegen. Damit kann die Refraktions-Technik zum besseren Verständnis von Mikro- und Submikro-Strukturen in der Materialwissenschaft eingesetzt werden. Mit der hier vorgestellten Refraktions-CT wurden Ermüdungsmechanismen an MMCs, bestehend aus SiC-Faser verstärktem Titan (Ti6242) untersucht. Die Messungen wurden am Röntgen-Messplatz der BAM (BAMline) am Synchrotron-Speicherring-BESSY in Berlin Adlershof durchgeführt.