Study of the effect of the morphology of initial powders on the structural and dimensional characteristics of SiC-based porous ceramic materials

Abstract

The realization of the necessary energy-efficient technological solutions for the production of highly porous SiC-ceramic materials requires appropriate research. The results of developing energy-efficient one-step methods for the synthesis of porous SiC-based ceramics and studying the characteristics of the obtained ceramics are presented. The effect of the morphology of initial powders on the synthesized product is considered. Ultrafine silicon carbide powders of two types, identical in characteristic particle size, but quite different in the surface morphology, were used as fillers in the synthesis of experimental samples of porous ceramics. The first one was obtained by the traditional furnace method (SiCf), the second one was synthesized by the technology of self-propagating high-temperature synthesis (SiCshs). It is shown that the particle morphology of initial powder components determines the structural parameters and characteristics of synthesized porous ceramics. The pore space parameters (average pore size, specific surface area, equivalent hydraulic diameter, permeability, etc.) can vary significantly. Porous ceramic materials synthesized on the basis of SiCf have an open porosity of 47%, high liquid permeability (up to 2 mDarcy), overwhelming dominance of α-SiC phase, and a narrow pore distribution with an average pore size of about 1 μm. High open porosity (more than 58 %), highly developed nanostructured pore space surface with an area of more than 12 m2/g, and wider pore size distribution (average pore size — 140 nm) are observed in porous ceramic materials based on SiCshs. The obtained results can be used to improve energy-efficient synthesis technologies and methods for predicting the properties of highly porous SiC-based ceramic materials. This will make it possible to create highly porous SiC ceramics within a priory predicted limits of effective applicability for the processes of ultrafiltration or catalysis.