Preparation and properties of high-purity alumina foams with tunable pore structures

This study developed high-purity alumina foams with tunable pore structures by employing a low-addition epoxy resin, appropriate foaming multiple and a modified polyethoxylated silicone (MPS). Results demonstrated that 3 times to 5 times of foaming multiples effectively control cell size (from 60–200 µm to 160–380 µm), density (from 1.12 g/cm 3 to 0.75 g/cm 3 ) and porosity (from 72.9% to 82.1%). Both the flexural strength (from 25 MPa to 10 MPa) and compressive strength (from 52 MPa to 13 MPa) of ceramic foams decreased rapidly with the increase of foaming multiples. MPS stabilizer enhanced foam stability, reducing average cell size by 37% at 60% addition. The usage amount of poly ethylene glycol diglycidyl ether is significantly reduced by 60%, which can greatly lower the material cost and the subsequent debinding cost.