Other protected systems with zinc

Zinc can be applied to the surface by different in other ways:

Electrometallization
Electrometallization is used for small parts that are not exposed to aggressive environments, because it allows the application of thin layers of zinc. It realized with the help of electrolytic systems.
Steel surfaces are degreased and cleaned of rust and residue oxides with the help of etching. Following this, steel parts are immersed in a zinc salt solution (electrolyte) and connected to a cathode DC source.
Anode joins to rod or a sphere of pure zinc. When the current is switched and zinc which present in electrolyte is transferred to the surface of steel while the anode (which is soluble) restores zinc content in electrolyte.
Thus there is only mechanical adhesion of zinc to steel, but not the alloy Fe + Zn.

Thermal zinc application of spray

Spraying use when it is impossible to use a hot-dip galvanizing. Steel is cleaned by grit blasting, no more than Sa 2.5 according to SIS 05 59 00. A special sprayer pistol fed by zinc in the form of wire or powder.
Zinc is melted by the flame of a gas or electric arc. Droplets of molten zinc sprayed on the surface of steel with compressed air.
Coverage becomes quite porous and the thickness of membrane may lie between about 30 microns to 200-300 microns or more.

Diffusion galvanizing

When the galvanizing diffusion process between iron and zinc forms a surface layer of Fe + Zn like in galvanizing, but it is limited in thickness between 15 and 40 microns.
Therefore it used in cases in which sufficient to obtain a homogeneous and thin membrane. It is also used for parts of a complex shape. The process consists in the fact that the parts cleaned, etched, stacked and packed with zinc powder and sand rotate in a drum heated to a temperature below the melting point of zinc. During a certain period of soaking at a certain temperature iron and zinc are mutually diffuse and form an alloy.

Mechanical coating

It is used mainly in the electronics industry or for small parts.
It allows the coating is usually for 12 - 15 microns, but there can be achieved large thickness (up to 75 microns). Mechanical coating consists of tumbling parts: firstly in an acid detergent solution and then in the copper solution, secondly with zinc powder and certain chemical agents.
Coatings exhibit a very uniform thickness including the details of a very complex shape. The surface is mat; there is no risk of hydrogen embrittlement. It allows treat tempered steel.

Colouring with the materials rich in zinc

Coloring with paints that are rich in zinc does not apply to metal coating methods. And it is staining procedure even if the paint membrane contains 90 - 94% of zinc in dry weight.
The paint is made from the finest zinc powder in suspension in an organic or inorganic carrier.  And it allows different pigmentation and membrane formation with good electrical conductivity and very high content of zinc.
Treatment can be carried out using a brush or spray pistol to obtain a desired coating thickness. It is used to repair damage in other types of zinc protection and to protect surfaces of steel products against the rust and mainly to put into operation ( like in the case of steel for construction, buildings, parts of ships and parts of bodywork of cars and trucks).
As in the case of hot spraying metallization the surfaces are cleaned by grit blasting Sa 2.5 according to SIS 05 59 00 because stripping and processing with a wire brush doesn’t guarantee satisfactory results.