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

Abstract Dense Al 2 O 3 –Cr 2 O 3 refractories having equimolar ratio of Al 2 O 3 and Cr 2 O 3 were developed by reaction sintering of calcined alumina and chromium(III) oxide in the temperature range 1600–1700 °C under reducing atmosphere. Effects of TiO 2 on the Al 2 O 3 –Cr 2 O 3 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 (Al 2 O 3 –Cr 2 O 3 solid solution) in all the sintered samples. Addition of TiO 2 imparts better densification and grain growth. Samples having 1 wt% TiO 2 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% TiO 2 show a diminutive increase in flexural strength after 6th cycle of thermal shock. The retained flexural strength of samples having 1 wt% TiO 2 after 12th cycle of thermal shock is much higher (101 MPa) than that of TiO 2 free samples (56 MPa).