Low temperature processing of highly porous silicon carbide ceramics with improved flexural strength

Excerpt

Porous silicon carbide ceramics have many industrial applications, such as hot gas particulate filters, molten metal filters, preforms for a metal–matrix and polymer–matrix composites, gas burner media, and light weight structural parts on account of their low density, thermal stability, chemical stability, high specific strength, and high thermal shock resistance [1‐6]. Different processing routes for highly porous SiC ceramics have been developed for specific applications to satisfy the associated requirements of porosity, pore size, and degree of interconnectivity. These manufacturing techniques are typically divided into three categories: replica techniques [4, 7], reaction techniques [8‐10], and gel casting techniques [11]. Recently, the production of porous ceramics from preceramic polymers has attracted considerable attention due to the expected improvement in the properties of porous ceramics and the potential cost-effective polymer processing [12‐15]. The synthesis of SiC ceramics via polymer precursor routes has attracted increasing interest in recent years [16, 17]. The most important advantage of this method is the ease of preparation at low processing temperatures. Polycarbosilane is a well-known polymeric precursor for SiC ceramics that is used for the processing of porous SiC ceramics. …