Gelcasting of alumina ceramics in the mixed acrylamide and polyacrylamide systems

Ceramic gelcasting without inhibition of gelation due to the presence of oxygen must be performed in a nitrogen atmosphere to avoid surface spallation of the green body, which is a complex and expensive process. This study shows that the surface spallation of ceramic green bodies gelcast in air could be suppressed by introducing a proper amount of water-soluble polymer, polyacrylamide (PAM), to the acrylamide monomer solution. The dispersion of Al2O3 powder in a water solution containing PAM was investigated. The rheological behavior and the gelling behavior of the alumina suspension were analyzed. Flexural strength and microstructure of the gelcast green and sintered bodies were studied.