Fabrication of porous alumina–zirconia ceramics by gel-casting and infiltration methods

• We prepare porous alumina ceramics by TBA-based gel-casting method.
• We prepare porous alumina–zirconia ceramics by infiltrating process.
• The content of zirconia can be adjusted effectively by infiltration times.
• The properties of porous ceramics can be controlled by the infiltration times.
• The porous ceramics possess both high porosity and high strength.

Porous alumina–zirconia ceramics were obtained by infiltrating porous alumina ceramics, which were prepared by tert-butyl alcohol (TBA)-based gel-casting method. Back scattering images of the fracture surface and energy dispersive spectroscopy were performed to obtain composition profiles on the fracture surface and across sections of the sintered composites. The porosity, pore size distribution and compressive strength were also investigated. The results show that the content of zirconia can be adjusted effectively by infiltration times and it decreases with increasing distance from the surface of the samples. The porosity and compressive strength can also be controlled by the infiltration times. With increases of the infiltration times from 1 to 3 cycles, the open porosity decreases slightly from 62.43% to 56.62%, while the compressive strength of the porous alumina–zirconia ceramics increases from 13.57 ± 1.21 to 26.87 ± 2.01 MPa, indicating that the porous ceramics with high porosity and high strength can be prepared by TBA-based gel-casting method combined with the infiltration process.