Substances of mainly organic nature containing C-H compounds that volatilize under the effect of the casting temperature.
The resulting gas atmosphere is oversaturated with carbon and has a reducing effect. Eventually, the oversaturation with C becomes so high that pyrolitic carbon is diffused on the surface of the solid material in the form of lustrous carbon. They are added to the bentonite bonded molding material in the form of C carriers. (s. Lustrous carbon).