Abstract: The effect of the addition of Cr₂O₃ micropowder on the normal temperature and high temperature performances, phase composition and microstructure of Al₂O₃-Cr₂O₃ refractories was studied by using fused chromium corundum and white corundum as the main raw materials, and using Cr₂O₃ micropowder to partially replace the fused chromium corundum fine powder. The results show that with the increase of the addition of Cr₂O₃ micropowder, (Al_1-xCr_x)₂O₃ solid solution is in-situ formed, which promotes sintering. And the apparent porosity of the material decreases first and then increases. The lattice constant of (Al_1-xCr_x)₂O₃ solid solution increases linearly with the increase of the addition of Cr₂O₃ micropowder, which conforms to Vegard’s law. The cold modulus of rupture and cold compressive strength increase first and then decrease with the increase of the addition of Cr₂O₃ micropowder. When the addition of Cr₂O₃ micropowder is 15% (mass fraction), the strength of the material reaches the maximum value. When the addition of Cr₂O₃ micropowder is 20% (mass fraction), the apparent porosity of the material increases and the strength decreases due to volatilization. The hot modulus of rupture of the material increases, and the residual strength rate of the material decreases first and then increases with the increase of the addition of Cr₂O₃ micropowder.

Key words: Al₂O₃-Cr₂O₃ refractory, Cr₂O₃ micropowder, (Al_1-xCr_x)₂O₃ solid solution, lattice constant, Vegard’s law, high temperature performance