Development of planar and cylindrical refractories with graded microstructure

Refractories play a key role in all high temperature applications in different industries like steel, glass, cement, energy plants etc. At the Fraunhofer IKTS the principle of manufacturing of refractories with graded properties is investigated. Aqueous ceramic tape casting and lamination technology are used for production of gradient structures. The used material system is Caaluminate/Al2O3. The graded pore structure shall result in improved thermal shock properties of the materials. Another concept is the insertion of ceramic platelets for crack deflection in case of thermal stresses. Besides planar structures also cylindrical designs are possible with a radial gradient of microstructure by applying a winding technology known from the paper industry. Investigations SEM-studies show the microstructure, fracture surfaces and the connection of the laminates which results in crack deflection.