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%.