(Room Temperature fine grain Zinc Phosphate Coating)
The ASFOCOAT-K process operated at room temperature produces a fine grain smooth and continuous Zinc Phosphate conversion coating for pre-paint treatment of steel. Applied by dip, it protects the base metal against corrosion and bonds supplementary coatings firmly to the surface. The chemically converted phosphate coating provides an excellent foundation for the lasting adhesion of paint.
While preparing any bath, always add chemical to water.
While preparing phosphating bath, first add the required amount of chemical to water and then add ACCELERATOR as stated below.
ACCELERATOR should always be dissolved separately in a small quantity of water and this solution is then sprinkled uniformly in the Phosphating bath.
False bottom should be provided in each tank to avoid parts from touching the bottom and to maintain bath free from sludge interference.
Phosphating bath should be decanted periodically to remove sludge settled at the bottom of the tank.
Manual swabbing with the degreasing solution is advisable for heavy oily contamination.
The quality and uniformity of the phosphate coating is directly dependent on the pre-treatment prior to phosphating. It is essential that the parts are absolutely free of oil, rust, dust,scales and other contaminants before immersing in the phosphating bath.
pH of passivating bath should be maintained between 3 5. Passivating bath should be discarded periodically and made fresh.
Additions to all chemical tanks should be made daily and regularly to obtain consistently uniform results.
All rinse water baths should be made fresh at least twice a week.
Activation with ASHPREP at 0.5% produces a compact dense zinc phosphate coating.
Phosphated parts which are not to be painted should be dipped in ASFOSIL DW56 for long term protection against corrosion.