Abstract: The present study focus on the preparation of Al₂O₃-CA₆ composite ceramics by co-firing ferrotitanium slag with Al₂O₃. CA₆ was formed through the reconstruction of ferrotitanium slag phase, with a long plate-like morphology and good compatibility with Al₂O₃. CA₆ was used as a toughening phase for ceramics. This study reveals the influence of CA₆ content and sintering temperature on the properties and microstructure of Al₂O₃-CA₆ composite ceramics by regulating the formula composition and sintering temperature. With the increase of CA₆ content, the bulk density, bending strength, and fracture toughness of ceramic samples all show a decreasing trend. As the temperature increases, the bulk density and bending strength of ceramic samples increase first and then decrease. The bulk density, apparent porosity, bending strength, and fracture toughness of two sets of samples containing 90% (mass fraction) Al₂O₃ and 85% (mass fraction) Al₂O₃, respectively, are obtained by sintering at 1 320 ℃. The values are 3.79 g/cm³, 0.22%, (385.01±21.67) MPa, and (5.33±0.21) MPa·m^1/2, respectively; 3.69 g/cm³, 0.12%, (371.22±9.65) MPa, (4.94±0.08) MPa·m^1/2, the utilization rate of titanium iron slag is higher than 75%, which is of great significance for the resource utilization of titanium iron slag.

Key words: composite ceramics, alumina, ferrotitanium slag, calcium hexaaluminate, toughening