Yttria magnesia co-stabilized zirconia refractories for application as functional components in continuous steel casting

Zirconia is one of the most promising functional refractory materials in continuous steel casting and is employed in areas with high thermal and chemical stresses such as the slag line, the nose of monoblock stoppers or the inlet area of submerged entry nozzles. The key for the application of zirconia in this application areas is a profound understanding of its thermomechanical and thermochemical properties that are influenced by the type and amount of stabilizer, the grain size and the thermal conditions during sintering and operation. Within this contribution coarse grained zirconia self-flowing castables based on a yttria stabilized zirconia co-stabilized by magnesia are developed; bars and a model monoblock stoppers are cast. After sintering the mechanical and thermo-mechanical properties are evaluated. The influence of different stabilizers and the contribution of the binder to the phase evolution during sintering and operation and thus the influence on the thermo-mechanical properties are investigated.