Abstract: A fluid composition additive for foundry casting sands enabling formation of lustrous carbon, including a liquid support and particles of at least one substance other than coal capable of forming lustrous carbon during metal casting.

Abstract: The models comprise an expanded or expansible polymer or copolymer generally used for the fabrication of such models. The polymer or copolymer contains an oxidizing agent comprising a nitroaliphatic compound that accepts expansion without substantial alteration of its oxidizing properties, that does not substantially modify the characteristics of the polymer or copolymer before, during and after expansion, that does not harm the quality of the metal that is cast, and that has a decomposition temperature essentially identical to that of the polymer or copolymer.