CaO-stabilized zirconiumoxide for refractory products

The use of zirconium oxide in the manufacture of continous casting nozzles is discussed. The deciding factors are the degree of stability of these zirconium oxides, the phase distribution cubic/monoclinic, as well as the processing method in manufacturing the nozzles. A share of CaO of 10-14 Mol% is necessary to fully stabilize the zirconium oxide. The expansion behaviour of monoclinic part-stabilized and fully stabilized zirconium oxide differs which considerably influences the resistance to sudden temperature changes. The influence of this varying thermal behaviour and the significance of the intermediate zones between the zirconium oxide grains are discussed. At present, microstructural investigations are being performed on continuous casting nozzles and investigations on the effect of impurities which for example, lead to part - destabilization of the cubic zirconium oxide with a silicon dioxide content of more than 1%. (HPH/LH)