Fundamental Research on the Densification of Alumina Ceramics by Ferrotitanium Slag

Ferrotitanium slag was used as a sintering aid to prepare high-performance alumina (Al2O3) ceramics by pressureless sintering at different temperatures. The bulk density, apparent porosity, bending strength, and hardness of the 99 wt% Al2O3 ceramics after sintering at 1420 degrees C were 3.91 g/cm(3), 0.16%, 389.37 (+/- 7.61) MPa, and 15.64 (+/- 0.16) GPa. On the other hand, those properties of 95 wt% Al2O3 ceramics after sintering at 1320 degrees C are 3.85 g/cm(3), 0.12%, 416.47 (+/- 6.79) MPa, and 15.44 (+/- 0.20) GPa. The effects of ferrotitanium slag on phase composition, microstructure, and mechanical properties of Al2O3 ceramics were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and other characterization tests. The results indicate that the addition of ferrotitanium slag accelerates the sintering process and the densification temperature of alumina ceramic is significantly reduced. The TiO2 in ferrotitanium slag causes the abnormal growth of alumina grains at high temperature.