Gelcasting is a novel method for molding ceramic powder based on a synthesis of concepts derived from traditional ceramics and polymer chemistry. Gelcasting of alumina is described in this paper. The process is based on the in situ polymerization of acrylamide monomers as the setting mechanism for forming the green body. It has the following features: slurries with high solids loading and low viscosity (1.8 Pa-s at 62 vol% solids), dried bodies containing less than 4 wt% binder, and the ability to fabricate complexshaped bodies. [

A series of low-toxicity gelcasting systems has been developed. The reagents used in these systems have very low acute toxicity. The new systems perform at least as well as, and in some cases better than, the original acrylamidebased system. The development of these systems is described herein, including the search for new gel compositions, the study of suspensions made with the new gel precursor solutions, and pyrolysis of the dried gels and gelcast parts. Applications of the new gelcasting systems include complex silicon nitride parts, large-diameter rings, rapid prototyping by green machining, and metal-powder gel casting.

Gelcasting, a ceramic forming process, was developed to overcome some of the limitations of current complex-shape forming techniques such as injection molding and slip casting while reducing the costs of shaping advanced ceramics. Gelcasting is based on the separation of the mold filling step from the setting step in these forming processes by utilizing the polvmerization of organic monomers into a chemical gel which holds the ceramic powder in place after the mold is filled. The simplicity of the process has attracted industrial partners and by collaboration between them and the developers, the process is being advanced from the laboratory toward industrial production.