Properties of porous alumina ceramics prepared by technique combining cold-drying and sintering

• We explored a simple and low-cost technique to prepare porous alumina ceramics with desired shapes.
• We discussed in detail the optimal temperature for preparing the porous alumina ceramics.
• We discussed the factors influencing the flexural strength of the porous alumina ceramics.
• We discussed in detail the factors influencing the porosity of the porous alumina ceramics.

For preparing porous alumina ceramics with desired shapes easily, a simple and low-cost technique combining cold-drying and sintering was explored. The optimal temperature for preparing the porous alumina ceramics is 1350 °C. The contents of CaCO3–SiO2 and dextrin in the green body have great effects on the properties of porous alumina ceramics. Due to a uniform microstructure and small pore size, the porous alumina ceramics prepared from the green body with 8 wt.% CaCO3–SiO2 show higher flexural strength and porosity. As the dextrin in the green body increases from 5 to 25 wt.%, the flexural strength decreases from 107 to 45 MPa with the porosity increasing from 36 to 54%.