Mechanical and thermal shock properties of size graded MgO–PSZ refractory

The effects of the mixture of coarse powder with fine PSZ powder on the thermal-mechanical properties of 10 Mg–PSZ samples were studied. The size graded specimens were injection-molded using 3.5 m% MgO–ZrO2 powders. The physical properties of the ZrO2 samples and five thermal shock parameters were measured and calculated. These properties included density (ρ), porosity (p), the ratio of m/(t+c+m) phase, fracture toughness (KIC), strength (σf), Youngʹs modulus (E), shear modulus (G), Poissonʹs ratio (ν), and the thermal expansion (α) between ambient temperature to 1100°C. The toughness and thermal shock resistance of the PSZ are controlled by the states of porous microstructure which can be represented by a parameter (nominal largest tolerable length of defects) at. The PSZ samples show two types of thermal shock behavior differentiated by comparing the value of at to the characteristic length Lf of the defects in the sintered PSZ. The states of the defects, i.e. porosity, are the microstructural evidence to explain the relationship between the thermal shock properties.