Aqueous gelcasting of yttrium iron garnet

N,N-Dimethylacrylamide (DMAA)/N,N′-methylenebis (acrylamide) (MBAM) system was used in the aqueous YIG (yttrium iron garnet) slurry. YIG powders were prepared by using Y2O3 and Fe2O3 as raw materials through the traditional oxide method. In order to reduce the viscosity and improve the stability of slurries, SD-03 (ammonium polyacrylate) was selected as the dispersant. Zeta potential, pH, dispersant dosage, solid loading and milling time have been optimized. The best conditions were pH 9.86, dispersant dosage 0.2 wt.% and milling time 9 h, which helped to prepare the concentrated slurry with low viscosity and good liquidity. The maximum bending strength of the green body could be up to 13 MPa. The shrinkage and deformation of shaped sintered bodies prepared through gelcasting were small after sintering. The sintering shrinkage, apparent porosity and bulk density were 17%, 0.17% and 5.07 g/cm3, respectively. The dielectric constant and dielectric loss were 14.0 and 2.06 × 10−4, respectively.