Reaction bonded silicon carbide

Reaction bonded silicon carbide, also known as siliconized silicon carbide or SiSiC, is a type of silicon carbide that is manufactured by a chemical reaction between porous carbon or graphite with molten silicon. Due to the left over traces of silicon, reaction bonded silicon carbide is often referred to as siliconized silicon carbide, or its abbreviation SiSiC. If bulk silicon carbide is produced by sintering of silicon carbide powder, it usually contains traces of chemicals called sintering aids, which are added to support the sintering process by allowing lower sintering temperatures.

Source: Wikipedia — Reaction bonded silicon carbide (CC BY-SA 4.0)