Preparation of high strength zirconia by epoxy gel-casting using hydantion epoxy resin as a gelling agent

In this paper, a water soluble hydantion epoxy resin (ER) was employed to prepare zirconia green bodies with high mechanical strength via epoxy gel-casting (EGC) for dental applications. The rheological properties and gelation behaviors of the suspensions, and the microstructure and mechanical strength of zirconia were systematically studied. The results revealed that solid loadings of up to 52.0 vol% could be achieved with the addition of 0.8 wt% dispersant. When the concentration of ER in the 52.0 vol% suspensions increased from 10.0 to 25.0 wt%, the mechanical strength of the resulting green bodies was enhanced from 40.96 ± 5.20 to 51.22 ± 12.01 MPa. A rough sketch of a pre-sintered zirconia crown was soft-machined from the green body consolidated from a 52.0 vol% suspension containing 10.0 wt% ER. The sintered body had a high mechanical strength of 942.77 ± 95.61 MPa.