Low-toxic gelcasting of zircon ceramics

Zircon (ZrSiO 4 ) ceramics are highly valued in various industries due to their exceptional physical and chemical properties. In the present work, zircon ceramics with high-density and desirable mechanical properties were successfully prepared using an aqueous gelcasting method, involving the use of a low-toxic and water-soluble monomer, N,N -dimethylacrylamide (DMAA), as the binder. A high solid loading and low viscosity zircon slurry was achieved by optimizing the pH and the dosage of the ammonium polyacrylate (PAA-NH 3 ) dispersant. Zircon green bodies fabricated through the gelcasting method exhibited uniform microstructures and relatively high mechanical strength exceeding 11.0 MPa. The impact of solid loading on the density, decomposition, flexural strength , micro-hardness, and microstructure of the final ceramics were carefully studied. Notably, the ceramics, prepared by solidifying the slurry with a 45 vol% solid loading and sintering the green body at 1550 °C for 2 h, exhibited a relative density of 96.3 %, high phase purity, a uniform microstructure, and the highest flexural strength of 407.9 MPa. The results demonstrate that mechanically robust dense zircon ceramics can be effectively prepared using the low-toxic gelcasting method.