Development of Ceramic Tapes for Thermal Shock Resistant Calcium Aluminate Refractory Materials with Graded Porosity

摘要

The ceramic tape casting technology is used for the development of carbonless refractory materials. For the tape casting process an aqueous slip of alumina, calcium carbonate and organic binder system is developed. Cellulose fibres and graphite platelets are also added to the ceramic slip to generate an adjusted pore volume after sintering of the ceramic which is very important for thermal shock properties of the material. For the tape casting slip aqueous binders are used. The organic binder has a great influence on the flexibility of the green tape and also on the further processing properties of the tape, for example the tape lamination. The tape casting slips are characterized by viscosity measurement. The orientation of the pore-forming agents can be influenced by the casting speed and casting thickness. Ion beam preparation and scanning electron microscopy are used for the characterisation of the green tape microstructure. The mechanical properties of the green tapes are estimated by tensile strength measurements in dependence on the casting direction and on the fibres orientation in x-y-layer.