Phosphating

Phosphating of metals is one of the most important surface treatment methods and many present metal finishing would not be possible without it.   

The phosphating sequence of the metal surface is normally broken down into the following stages: degreasing and cleaning, derusting and descalling, activation, phosphating and post-treatment.

The main areas of application of phosphating are: for lubrication during cold forming (wire drawing and tube drawing, deep drawing, et cetera), for corrosion resistance (corrosion protection with no subsequent treatment - corrosion protection in conjunction with organic coatings, corrosion protection in conjunction with oils and waxes, et cetera), to reduce break-in wear on adjacent moving surfaces, for torque-tension requirements on fasteners and for bonding organic coatings to metals

Of the many phosphating plants, the following are of industrial importance: zinc phosphate, iron phosphate, manganese phosphate. Such phosphating systems are predominantly applied to iron and steel, as well as zinc surfaces whereas other metals which can be phosphated like aluminum and magnesium, are less commonly processed by this method.