Forming Alumina Parts Using Acrylamide Gels

Today, the fabrication of complex-shaped ceramic parts in large quantities has been limited to the processes required extensive and expensive machining (i.e., injection moulding or pressure slip-casting). These technologies for shaping ceramics, however, possess several shortcomings that limit their use as a complex-shape forming method. Because of these limitations, "gel-casting" which was lacking in above deficiencies, has been proposed as a general and desired method for shaping any ceramic powder. In this work, gel-casting of a-alumina is investigated based on in situ polymerization and gelation of acrylamide monomers as the setting mechanism for forming the green part. Special attention was paid to the preparation of fluid, castable slurries with a high loading level of *a-A12O4 ( > 80 wt.%) and low viscosity (0.65 Pa.s) by using polyelectrolyte dispersants (i.e., poly(methacrylic acid) salts), also gelation of acrylamide (effect of gelation factors on idle time), mould materials, drying of parts through the liquid desiccant drying method and its comparison with conventional drying technique, green machining, debinding and sintering.