Reaction Bonded Silicon Carbide (RBSC)

Reaction Bonded Silicon Carbide (RBSC)

Chemical Formula
SiC/Si

Background
Vacuum furnace apart from its main uses in metallurgy, abrasives and refractories, silicon carbide is also used in structural applications where high temperature strength or high stiffness to weight ratios are required.
The demand for more energy efficient engines and the need to replace critical metals drove the development of a number of ceramic materials and processes, particularly for high temperature gas turbine engines. Reaction bonded silicon carbide resulted from these investigations.

Processing
Although silicon carbide can be densified with high temperature and pressure, the process is not a viable commercial process.
Reaction bonded silicon carbide is made by infiltrating compacts made of mixtures of SiC and carbon with liquid silicon. The silicon reacts with the carbon forming silicon carbide. The reaction product bonds the silicon carbide particles. Any excess silicon fills the remaining pores in the body and produces a dense SiC-Si composite.
The ratio of SiC to carbon and particle size distribution varies widely in practice. Articles are produced with a wide range of compositions and properties. At one extreme, carbon fibre felt or cloth can be infiltrated with liquid silicon, whilst at the other extreme, an impervious silicon carbide body can be made with a small amount of carbon.
Most reaction bonded silicon carbide is made with formulations that contain an organic plasticiser, carbon and silicon carbide particles. This mixture is ideally suited to near net formation by pressing, injection moulding or extruding. Further, since the reaction process typically gives a dimensional change of <1%, manufacturers have excellent control of component tolerances.

Edited By Eric

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