Gelcasting, a near net shape technique

摘要

Gelcasting is a new ceramic forming technique getting worldwide attention. The process is based on the casting of a slurry, containing powder, water and water-soluble organic monomers. After casting the monomer, the mixture is then polymerized to form gelled parts. Drying, burning out and sintering complete the manufact uring route. The process is generic and can be used for a wide range of ceramic and metallic powders. It is a suitable technique for the fabrication of near net shape prototypes or small series using cheap moulds. In contrast with slipcasting, gelled parts are more homogeneous and have a much higher green strength. Gelcast parts contain only a few percent of organic components making binder removal much less critical compared to injection molding. In this contribution, we describe our experience of the gelcasting of Al_2O_3 powders. Until now special attention was given to the preparation of slurries with a high Al_2O_3 load, to the gelcation itself, catalytic or thermal, to the choice of mould materials, to the drying step and to green machining.