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Open Access Research Article Issue
Microstructure and properties of porous Si3N4 ceramics by gelcasting-self-propagating high-temperature synthesis (SHS)
Journal of Advanced Ceramics 2022, 11 (1): 172-183
Published: 06 November 2021
Downloads:306

Porous silicon nitride ceramics have attracted a considerable attention due to their excellent overall performance, but poor porosity homogeneity and structural shrinkage induced by prolonged high temperature sintering limit its further application. Herein, as a three-in-one solution for the above issues, for the first time we develop a novel approach that integrates the merits of gelcasting-SHS (self-propagating high-temperature synthesis) to prepare porous Si3N4 ceramics to simultaneously achieve high porosity, high strength, high toughness, and low thermal conductivity across a wide temperature range. By regulating the solid content, porous Si3N4 ceramics with homogeneous pore structure are obtained, where the pore size falls inbetween 1.61 and 4.41 μm, and the elongated grains are interlaced and interlocked to form micron-sized coherent interconnected pores. At the same time, porous Si3N4 ceramics with porosity of 67.83% to 78.03% are obtained, where the compressive strength reaches 11.79 to 47.75 MPa and fracture toughness reaches 1.20 to 6.71 MPa·m1/2.

Open Access Research Article Issue
Preparation and characterization of monodispersed spherical Fe2O3@SiO2 reddish pigments with core-shell structure
Journal of Advanced Ceramics 2019, 8 (1): 39-46
Published: 13 March 2019
Downloads:22

The α-Fe2O3@SiO2 reddish pigments with core-shell structure were successfully prepared by hydrothermal and Stöber methods. The structure, morphology, and chromaticity of the synthesized pigments were characterized by XRD, SEM, TEM, FTIR, XPS, and colorimetry. The results indicated that the as-prepared pigments have the characteristics of narrow particle size distribution, high dispersion, and good sphericity. The α-Fe2O3@SiO2 reddish pigments were uniform and well dispersed in solution. In addition, the pigments with different shell thickness were also prepared, and the effect of shell thickness on the color performance of the pigments was discussed.

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