Agents for additional treatment of the phosphating coatings

Pragokor BP is a non-foaming agent for the passivation of phosphated steel. It contains neither chromates and nitrites nor other hazardous substances. It may be applied by immersion or spraying techniques just after the final rinse step after the phosphating process. The bath itself is characterized by a low salts content which results in a suppressed adverse affect on the waste water treatment process. In the bath, the microscopic pores or other inhomogeneities in the phosphate coating are passivated against corrosion, the passivating affect on steel being more pronounced compared with many other six-valence chromium based passivating agents. The surface passivated is fully compatible with all types of organic coatings (water-based, solvent-based, cataphoretic, powder coatings etc.) and the passivating layer will boost substantially the overall protective performance of the combination phosphate-organic coatings.

Low-foaming, both nitrites and chromates-free, emulsion-based agent with inhibition and neutralization affects, suitable for both temporary as well as inter-machinery operations-protection of steel, cast-iron and copper alloys against corrosion. It proves very well for the sealing and preservation of phosphate and alkaline blackening coatings and, unlike other preservation agents for metallic substrates, will not impede a possible subsequent painting. It should be applied by immersion or spraying techniques as the last operation just before drying, after the last rinse step. Once passivated, the passivation affect remains and the surface treated may be again rinsed in demineralised water because the corrosion inhibitors contained are strongly bonded to the surface by chemisorption. The surface passivated is compatible with all types of paints and powder coatings, only in the case of water-based paints the compatibility should be checked at first as the surface becomes a bit hydrophobic after the passivation. The feature of the agent is the high anticorrosion performance functioning even at a very low start-up concentration of the bath. To boost the inhibition affect, it is convenient to add the agent into the both degreasing as well as tumbling baths of the pH value ranging from weak acid to strong alkaline which results in passivation of the surface and anticorrosion protection in one combined surface treatment operation. In such a case, the compatibility with subsequent painting, if required, should be checked thoroughly at first. The addition of Pragokor Inhibitor 51 into the baths of the cationic-based agents must be avoided.