Silicon carbide (SiC) is a synthetic, semiconducting fine ceramic that excels in a wide cross-section of industrial markets. Manufacturers benefit from an eclectic offering of silicon carbide grades due to the availability of both high-density and open porous structures. Combined with the material’s outstanding high-temperature strength and thermal shock resistance, alongside inherently impressive mechanical properties, silicon carbide is one of the most versatile refractory ceramics worldwide.
Silicon Carbide: Grades, Formats & Bonding Types
Silicon carbide grades can be distinguished by their porosity and composition. Remarkably dense (<99.9%) silicon carbide ceramics are typically engineered via one of two methods: reaction bonding or sintering.
Sintered SiC, like Saint-Gobain’s proprietary Hexoloy® brand, is produced at extremely high temperatures (~2000°C) in inert atmospheres using a range of forming methodologies, including dry-pressing and extrusion. Reaction bonded, or siliconized, silicon carbide is formed using a porous carbon feedstock and molten silicon via additive forming, casting or extrusion. Each of these fully-densified silicon carbide ceramics achieves exceptional chemical and mechanical properties in extreme end-use temperatures exceeding 1400°C (2552°F).
Open porous silicon carbide ceramics are similarly formulated via one of two methods: recrystallization or bonding. Recrystallized SiC ceramics can be cast or extruded, while bonded SiC ceramics can be pressed, cast, blended, or extruded depending upon the bonding method used. Among these methods are oxide-, nitride- or oxy-nitride, and sialon bonding. The latter utilizes aluminum (Al2O3) as an additive agent to improve the ceramic’s corrosion resistance in extreme use conditions, such as furnace stack architectures. SiC ceramics are also available in the silicon-nitride bonded, silicon infiltrated, and oxide-bonded conditions.
Saint-Gobain has spent years developing a uniquely broad understanding of the thermomechanical and chemical properties of silicon carbide ceramics developed via numerous distinct manufacturing avenues. As a result, Saint-Gobain has now positioned itself as one of the foremost silicon carbide ceramic suppliers worldwide. With a selection of industry-trusted products on offer, Saint-Gobain routinely services demanding application areas with uniquely tailored solutions. Examples include: