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2011
Presentation
Titel
Lamination techniques for new multilayer for thermal shock resistant refractories based on the material system calcium-aluminate
Titel Supplements
Presented at XVII. International Conference on Refractories Praha May, 10th-11th, 2011
Abstract
Refractories play a key role in all high temperature applications and cover all the strategic industries such as steel, cement, glass, petrochemicals, energy plants etc. Most of the known refractory materials based on a high carbon content to guarantee good thermoshock behaviour. But the use of carbon cause in two problems. First the good thermal conductivity of the carbon results in a high loss of heat and high costs for heating. Second the migration of the carbon impurifies e.g. the molten steel and makes it difficult to produce high purity steels. At the Fraunhofer Institute for Ceramic Technologies and Systems the principle of manufacturing of carbon-free refractory components by multilayer technology is investigated. The material is Ca-aluminate/Al2O3. The manufacturing of multilaye r composites by aqueous ceramic tape technology allows the production of components with large dimensions and gradient structures regarding porosity and phase composition, which will yield to improved thermal shock properties of the materials. The presentation will show the results of different characterization techniques for laminated green bodies and sintered multilayer. The green bodies are characterized by electron microscope after ion beam preparation to get information about the microstructure and the arrangement of pore-forming additives. A computer tomography scanner allows looking for possible delaminations between the different tapes after the lamination, which will results in big defects in the sintered multilayer. The porosity of the sintered multilayer is characterized by a n electron microscope on cross-sections and by buoyancy-flotation method. The mechanical characterization is done by measurement of 4-point-bending strength on virgin probes and probes which were shocked with different temperature differences. Also the influence of the porosity on the mechanical behaviour was investigated.