Phosphating of steel

• Mangan phosphate
• Zinc – calcium - phosphate (thin layer phosphate)

 

Chemical reactions of metal surfaces caused by watery phosphate solutions result in the generation of a conversion layer that consists of highly adhesive metal phosphates occur during the phosphating process. Phosphate plated metals have numerous applications and are deployed in a variety of sectors. Thanks to its properties, phosphating plays a particularly important role in metal and materials technology. Because of its solid adhesion properties, it is frequently used to prepare for the actual coating or painting process. This finishing method is usually used in conjunction with steel.  

 

Phosphating - process sequence

First, oxides and oils have to be removed from the metal surfaces prior to finishing. The work piece to be treated is stained in the first step. Metal oxides are moved into the solution under the emergence of hydrogen. In the main phosphating step, the metallic surface is immersed into phosphoric acid. The metal dissolves and forms salt corrosion products. An even crystal layer is created on the surface that protects the metal from further acid attacks and acts like an insulation. This rough phosphate crystal layer is the ideal adhesion base for the subsequent paint job or for the absorption of oils and lubricants.

 

Phosphating offers numerous advantages

As a finishing method, phosphating of steel delivers a lot of benefits. Besides providing temporary protection from corrosion, which is the result of phosphating on steel, its input and sliding qualities are also improved.  Another positive aspect of phosphating is its impact on in particular the toothing components, since it reduces their fragility. The process, which is frequently used in conjunction with rubber-metal combinations, also delivers connector adhesion strength.