Reaction-sintered silicon carbide (Si-SiC) is produced from a mixture of powdered a-SiC, graphite and organic binding agents. This mixture, compressed into moulded parts, is heated to around 1000 °C, resulting in carbonization of the binders. If necessary, the mouldings are machined prior to immersion in liquid silicon for the final process of silication at between 1500 and 2200 °C. The liquid silicon penetrates the shaped ring and reacts with the carbon to form secondary SiC. Any pores are filled with silicon. There is no shrinkage of note. On account of the free silicon (approximately 10% content), this material can be used only up to a pH-value of around 10. The microstructure is fine-grain or rough/fine-grain, depending on the starting material. Reactionsintered silicon carbide is not as brittle as pressureless sintered silicon carbide. For material characteristics see materials for seal faces and stationary seats.

Microstructure of Si-SiC (100:1)