Phosphating is a process in surface protection metallurgy of metals, which consists of covering metal parts with zinc, iron and manganese phosphates, both in the form of neutral phosphates (PO4−3) and monoacids (HPO4−2). Due to the low solubility of the phosphates of these chemical elements, they are deposited on the metal surface where the protection in the form of a thin layer of crystals is intended after contact with their solutions, under certain conditions.
They serve as a conversion coating in which a diluted solution of phosphoric acid, which is applied via spray or immersion, chemically reacts with the surface of the part being coated to form a layer of insoluble crystalline phosphates.
| Treatment Description | Treatment Code | Classification | Layer |
| MANGANESE PHOSPHATIZATION | FOMN | TYPE 1 | 05A25 |
| ZINC PHOSPHATIZATION | FOZN | TYPE II | 05A25 |
