Structure Formation in Silicon Carbide–Alumina Composites during Electroconsolidation

Abstract

Some possible methods for improving the hot pressing of SiC ceramics are reviewed. The method of liquid-phase sintering is described as a way to increase the physical and mechanical properties and to reduce the energy consumption of the pressing process. An example of liquid-phase sintering of silicon carbide ceramics by the method of hot pressing with use of a direct electric current for the introduction of a small amount of oxide impurities is given. The peculiarities of structure formation and the properties of the composite material based on silicon carbide micropowders, which is obtained by hot pressing in vacuum and heating with a direct high-ampere current transmitted through a graphite mold, are described. The microstructure and the physical and mechanical properties of composites of different compositions have been studied. The optimal composition of the initial mixture and the most optimal sintering temperature are determined. The comparison of the physical and mechanical properties of the obtained composite materials is given.