Fused silica ceramics were prepared by slip casting method with various particle sizes (d50 ≈ 2.31 μm, 19.79 μm, and 71.46 μm) from three types of fused silica powder. The influence of raw material grain composition on the viscosity of slurry, bulk density, porosity, water absorption, and flexural strength of the fused silica ceramics was investigated. The slurry viscosity was measured by an XND-1 viscometer. The bulk density, porosity, and water absorption of the sintered samples were obtained by the Archimedes method. The flexural strength was measured by a three-point bending test. The phase composition and microstructure of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that when the grain composition was 5 : 3 : 2, slurry viscosity was 150.79 mPa·s with solid content of 75%, the fused silica ceramic particles were packed most tightly and demonstrate bulk density of 2.02 g/cm3, porosity of 6.99%, water absorption of 3.47%, and flexural strength of 51.27 MPa.

Keywords: Fused silica ceramics, Grain composition, Slip casting, Bulk density, Flexural strength