Zinc electroplating (Zn)

From the weakly acidic chloride electrolyte for galvanizing, it is possible to galvanize objects made of low alloy structural steels, alloy steels, gray cast iron, copper and copper alloys. Items can be galvanized on racks or in barrels, depending on the dimensions of the item and the technical requirements.

OPĆI I TEHNOLOŠKI UVJETI ZA CINČANJE

Galvanizing on racks

Semi-automatic line  with 2 baths with 4500 liters of electrolyte. Maximum object dimensions:

  • length up to 3300 mm
  • height up to 1250 mm
  • width up to 450 mm

Coating thickness according to DIN and ISO standards is from 5 to 25 microns.

Zinc electroplating in barrels

Small items such as screw goods, washers, nails, nuts, etc. are galvanized in barrel. The smallest dimensions of the objects that can be galvanized in this way are 1.5 mm in diameter (eg nails 1.5 mm thick). The thickness of the coating is  from 5 to 12 microns.

Chemical treatment of galvanized surface

It is common for the galvanized surface to undergo a chemical passivation or chromatization process after rinsing to increase the corrosion resistance of zinc as well as to achieve decorative properties.

We have the following types of passivation:

  • blue chromate – Cr (III) – mark A or B
  • thick layer chromate – Cr (III) – code Cn
  • yellow chromate – code C
  • olive-green chromate – code D
  • Versiegelung (thin film varnish) – code T2

Cr (III) passivation meets EU ELV and RoHS directives.

If necessary, galvanized and chromated objects can significantly increase the anti-corrosion properties by treating them with special varnishes, which polymerize after drying – our line has this possibility!

In case the galvanized surface is intended for later painting (fences, piers, doors, etc.), we recommend olive-green passivation because of its corrosion resistance and good adhesion of the coating, which is preceded by a suitable zinc primer (eg epoxy primer).

Dual Protection (Duplex System)

Special protection against corrosion is given by double protection, ie galvanizing and varnishing by conventional methods, using zinc primers, or electrostatic powder coating (plastification).

The application of this system avoids the possibility of corrosion of iron beneath the coating, which separates the coatings from the substrate by the effect of the wedge due to the increase in the volume of corrosion products.