Thermo-mechanical behavior of Al2O3–Cr2O3 refractories: Effect of TiO2

Dense Al2O3–Cr2O3 refractories having equimolar ratio of Al2O3 and Cr2O3 were developed by reaction sintering of calcined alumina and chromium(III) oxide in the temperature range 1600–1700 °C under reducing atmosphere. Effects of TiO2 on the Al2O3–Cr2O3 refractories were investigated with respect to densification, thermal expansion, microstructure, flexural strength at different temperatures and thermal shock resistance behavior. XRD studies revealed the presence of only one phase (Al2O3–Cr2O3 solid solution) in all the sintered samples. Addition of TiO2 imparts better densification and grain growth. Samples having 1 wt% TiO2 exhibit optimum flexural strength at room temperature as well as at elevated temperatures. Thermal shock resistance investigation from 1200 °C to room temperature revealed that samples having 1 wt% TiO2 show a diminutive increase in flexural strength after 6th cycle of thermal shock. The retained flexural strength of samples having 1 wt% TiO2 after 12th cycle of thermal shock is much higher (101 MPa) than that of TiO2 free samples (56 MPa).