Coating materials are applied to high-load mold surfaces to obtain better surface quality of cast parts and to prevent occurrence of casting defects (e.g. veining). Today, they are available in liquid to pasty consistency; coating materials in powdered form are very rare.
Fig. 1:Mold material coating, (Foseco Foundry Division Vesuvius GmbH)
Additional references:
Facing coat
Burn-off facing coat
Mold sand-based casting defect