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Ceramic and metal-ceramic components with graded microstructure

 
: Scheithauer, Uwe; Schwarzer, Eric; Otto, Christian; Slawik, Tim; Moritz, Tassilo; Michaelis, Alexander

:

Lin, Hua-Tay (Ed.); Hemrick, James (Ed.); Singh, Mrityunjay (Vol. Ed.); Ohji, Tatsuki (Vol. Ed.); Michaelis, Alexander (Vol. Ed.) ; American Ceramic Society -ACerS-, Westerville/Ohio:
Advanced and Refractory Ceramics for Energy Conservation and Efficiency : A collection of papers presented at CMCEE-11, June 14-19, 2015, Vancouver, BC, Canada
Hoboken, NJ: Wiley, 2016 (Ceramic Transactions 256)
ISBN: 978-1-119-23458-6 (print)
ISBN: 978-1-119-23459-3 (online)
DOI: 10.1002/9781119234593
pp.149-160
International Symposium on Ceramic Materials and Components for Energy and Environmental Applications (CMCEE) <11, 2015, Vancouver>
Deutsche Forschungsgemeinschaft DFG
SPP 1418; MI 509/10-2; FIRE II
English
Conference Paper
Fraunhofer IKTS ()
graded microstructure; metal-ceramic; Tape casting; Multilayer; Stainless steel; Zirconia; carbon-free refractories; green tapes

Abstract
The development of ceramic and metal-ceramic components with graded microstructures concerning material or porosity opens new fields of application. Components with different porosities combine different properties in the gradient structure regarding thermal conductivity and capacity, density, mechanical strength, and elastic modulus. Graded microstructures as combination of two or more materials result in innovative, multi-functional combinations, such as hard and ductile, electrically or thermally conductive and insulating, magnetic and nonmagnetic for metal-ceramic composites. At the Fraunhofer IKTS the manufacturing of components with graded microstructure by multilayer technology was investigated. To demonstrate the possibilities of this technology carbon-free refractories with graded porosity, made of Ca-aluminate/Al2O3 or MgO-stablized ZrO2, were developed to achieve properties which are equivalent to the carbon-containing refractories. Other demonstrators combine stainless steel and zirconia to address applications like filters or cutting tools. Single green tapes were manufactured by aqueous ceramic tape casting as an environmental-friendly production technology. Thereby, different amounts of pore forming agents were added to the different used green tapes to adjust the porosity. To realize a graded microstructure different green tapes with defined amounts of pore forming agents were laminated to one multilayer by using a special joining suspension. SEM-images of cross-sections of the sintered components verify the perfect connection between the single layers within the sintered structures, which combines porosities between 0% and 25% (MgO-ZrO2) or 30% and 45% (CaAl) as well as steel and zirconia in one composite.

 

At the Fraunhofer IKTS the principle of manufacturing of components with graded microstructure by multilayer technology is investigated. The main goal was the production of components with enhanced properties by the combination of different materials or porosities in one component. To demonstrate the possibilities of the multilayer technology carbon-free refractories, made of Ca-aluminate/Al2O3 or MgO-stabilized ZrO2 with graded porosity, were developed to achieve properties which are equivalent to the carbon-containing refractories. Other demonstrators combine stainless steel (17-4PH) and zirconia to address applications like filters or cutting tools. The manufacturing of multilayer composites by aqueous ceramic tape technology allows an environmental-friendly production of components with large dimensions and gradient structures regarding porosity and phase composition. Thereby, different amounts of pore forming agents added to the different used green tapes adjust the porosity. The resulting different properties in the gradient structure shall result in improved thermal shock properties of the materials. To combine different materials in one multilayer different green tapes were produced and laminated to one multilayer.Not only planar structures, but also cylindrical structures with a radial gradient of the microstructure and the resulting properties can be realized by applying a winding technology known from the paper technology.For the lamination of the multilayer, a special joining suspension was used. SEM-images of the sintered components show the perfect connection between the single layers within the produced structures.

: http://publica.fraunhofer.de/documents/N-414813.html