Zinc phosphating

This is a zinc and iron phosphate based treatment applied to parts in iron, carbon steel with low alloy content, and cast iron.
The resulting colour varies from light to dark grey depending on the composition of the material and its surface (mechanical working and any previous thermal treatment). In addition to corrosion resistance, the phosphating can fulfil an extremely useful role for anchoring other applied materials like rubber, Teflon, stearate, laccar, paint, etc.

The products we utilise for this treatment ensure compact and uniform microcrystalline phosphate layers of 14 to 18 g/m² (7 – 9 µ), providing improved corrosion resistance after treatment with high-protection emulsifiable oil. We can provide an alternative oil-free finish on request.

Standard Specifications:

UNI EN ISO 9717:2017      =      Fe/Znph/T4

(UNI  EN 12476)

ASTM F 1137 (corrispondente a UNI 3740/6)


And Marelli Avio, Piaggio, Iveco, Fiat, Oto Melara, Breda Energia, Pirelli, Volvo, McLaren, Volkswagen, BMW, Mercedes-Benz, Brose , Bosch, Caterpillar and so on


photo SEM microscope

Special Application

Phosphating for paint priming, other coating materials, cold forming

Summarizes recommendations for phosphate conversion coatings (Zinc phosphate coatings) to ensure good adhesion of paints, varnishes, similar coating materials, sealants, PTFE, wax, grease or oil.
An excellent conversion treatment for paint priming, in particular when low mass surfacing is required to improve resistance to mechanical attack and offering combined impact and corrosion resistance.

The low mass of the layer also increases electrical conductivity which is particularly advantageous for electrophoretic painting.

Phosphatic pre-treatment considerably increases the corrosion resistance of parts.

The treatment is light grey and velvety in appearance.


Zinc phosphate conversion coating are preferred to facilitate cold forming.

Zinc phosphate coatings should be neutralized after rinsing, by treatment with a weakly alkaline aqueous solution.

Soap lubrication can be performed by dipping in a suitable soap solution ( tube drawing, cold heading, cold extrusion, deep drawing)