Gelcasting, a near net shape technique

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 polymerised to form gelled parts. Drying, burning out and sintering complete the manufacturing 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 moulding. In this contribution, we describe our experience of the gelcasting of Al2O3 powders. Until now special attention was given to the preparation of slurries with a high Al2O3 load, to the gelation itself, catalytic or thermal, to the choice of mould materials, to the drying step and to green machining.