A simple and effective method for gel casting of zirconia green bodies using phenolic resin as a binder

A simple, effective method for fabricating zirconia green bodies is described that utilizes phenolic resin as a binder in the gel casting process. Both the zeta potential of zirconia particles and the rheological behavior of the slurries were measured. To prepare stable, homogeneous, fluidic zirconia slurry with high solid loading, the zeta potential was adjusted by varying the phenolic resin content of the premixed solution. This represented a departure from normally adjusting the slurry pH by using an acids, alkali or dispersants. To promote gelation of the slurry, a curing agent was added. Gel casting a mixture of a 42 vol.% zirconia slurry containing 13 wt.% phenolic resin yielded an easily sintered, very homogeneous green body with the desired strength. The gelation time of the slurries and the mechanical strength of the green bodies were controlled by adjusting the quantity of the curing agent in the slurries.