抄録
The inert sintering of gelcast formed alumina is an attractive way to fabricate homogeneous electrical conductive alumina. In this method, the gel-binder networks responsible for the strength of the green part are in-situ pyrolyzed and sintered to yield carbon networks required for electrical conduction. The resulting sintered part is a composite of alumina and carbon with an amount dependent on the gelcasting chemicals used. However, the presence of carbon is expected to influence the microstructural features of alumina. In this study, the dried gelcast alumina made of different gelcasting compositions were sintered in inert atmosphere and the resulting microstructural characteristics were evaluated. Several methacrylamide-based slurries and 2-hydroxyethyl methacrylate (HEMA)-based slurry were gelcasted, dried and sintered in argon gas at 1700oC. Their corresponding microstructural characteristics were compared to pure alumina sintered in oxygen atmosphere. Results showed that the microstructures of all argon-sintered alumina differ significantly from oxygen-sintered alumina. This microstructural difference is attributed to binder decomposition rate and the presence of pyrolyzed carbon, which are explained in this presentation.
