3. Solvent degreasing

The high dissolving power of oils has made organic solvents preferred partners in the degreasing of metallic materials. The removal of the adsorbed greasy film can be explained schematically by the breaking of the bond between the polar ends of the oil and the metal surface, for example, followed by the adsorption of the solvent, reversibly or not, onto the metal interface.

The first solvents used were derived from coal (benzol) or petroleum (white spirit, etc.). Their flammability led to a preference for chlorinated and/or fluorinated solvents, which are non-flammable and therefore do not require explosion-proof installations.