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0.95(Ca 0.88 Sr 0.12 )TiO 3 -0.05(Bi 0.5 Na 0.5 )TiO 3 ceramics were prepared by a soft chemistry method (co-precipitation), which was done at lower temperature and shorter reaction time than the conventional solid-state reaction method. The thermal decomposition process, phase composition, microstructure and dielectric properties of the samples were characterized by TGA, X-ray diffraction, scanning electron microscopy and precision impedance analyzer. Comparing to the conventional solid-state reaction method, the co-precipitation method not only effectively lowered the calcination temperature of (Ca 0.88 Sr 0.12 )TiO 3 powders from 1100 to 850°C and the sintering temperature from 1275 to 1225°C, but also improved the sintered properties and the dielectric properties, especially the Q × f value increased from 8116 to 8754 GHz and the τ f decreased from + 639 to + 602 ppm/°C. Moreover, the ceramics prepared by co-precipitation method showed more uniform, fine-grained microstructure. The optimal integrated microwave dielectric properties ( ε r = 180, Q × f = 8754 GHz, τ f = + 602 ppm/°C) were achieved for 0.95(Ca 0.88 Sr 0.12 )TiO 3 00.05(Bi 0.5 Na 0.5 )TiO 3 ceramics sintered at 1225 °C for 4 h. [ABSTRACT FROM AUTHOR]

Gelcasting is a colloidal processing method for fabricating high-strength and complex shape ceramic green bodies. However, industry has been reluctant to use the gelcasting technique because the most commonly used gel, acrylamide ( AM), is a neurotoxin. Here, we report an attempt at the gelcasting of fused silica glass using a natural and nontoxic gel, glutinous rice flour ( GRF) as binder. The GRF-based aqueous system was found to behave excellently in the gelcasting process. Flexural strength of fused silica green bodies solidified with only 3 wt% GRF is up to 11.87 MPa. Bulk density and flexural strength of fused silica glass sintered at 1275 °C are 1.75 g/cm3 and 47.02 MPa, respectively. [ABSTRACT FROM AUTHOR]