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–ZrO 2 powders. The physical properties of the ZrO 2 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 ( K IC), strength ( σ f), Young's modulus ( E), shear modulus ( G), Poisson's 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) a t. The PSZ samples show two types of thermal shock behavior differentiated by comparing the value of a t to the characteristic length L f 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.