Properties of Al2O3 ceramics consolidated with sulfanilic acid

Al2O3 ceramics were prepared through colloidal processing and consolidation process. Initially, Al2O3 powder was dispersed in aqueous medium to make 60 vol% suspensions with 1.5 wt% dispersant. After mixing to obtain well-dispersed slurries, a minor amount of sulfanilic acid was added and the slurries were consolidated in a nonporous mould. Al2O3 green samples exhibited a homogeneous microstructure with uniform distribution in pore size. After sintering at 1600 °C in air, the microstructure, hardness and toughness were characterized. Toughness as high as 6.40 MPa m1/2 was obtained for Al2O3 samples with sulfanic acid/Al2O3 mass ratio as 5.74 mg/g. Results showed that it was possible to consolidated Al2O3 slurries with homogeneous microstructure and high mechanical properties.