phosphation

At present, phosphation is carried out with four compounds, Mg, Fe, Zn and PO₄. TThe treatments applied to the various rinses are conventional (neutralisation, coagulation, sedimentation) and can be carried out by combining them with the water from other surface treatment workshops for instance.

The chrome passivation that historically followed this stage has now been abandoned. It has been replaced by an organic coating produced by a process that allows coated metals to be welded without being damaged. This eliminates the treatment of a waste stream that was particularly toxic because it contained hexavalent chromium.