Zinc plating

Corrosion of iron occurs when it interacts with oxygen in the air. To avoid this and prolong the life of the product several times, it is necessary to carry out a set of protective measures. Zinc coating is usually used. This process consists in applying a layer of zinc to the surface of the product. This process can take place in various ways.

Variation of the operation

To date, the progressive development of scientists can use the following types:

- cold galvanizing of metal;

- hotter;

- diffusion;

- Electrolytic;

- Shopirovanie;

- gas dynamic.

Let's talk about each method separately.

Description of the types of galvanizing

Two types can be considered common: hot and electrolytic. In this case, the first method, called galvanic, requires the installation of an entire production line. But this method is ineffective against corrosion. However, it gives the product a beautiful and shiny appearance. So electrolytic zincing is used only for decorative purposes.

Hot-dip galvanizing is a very costly exercise. For its implementation, the part must completely immerse in molten zinc. Such a process is produced only on an industrial scale and requires a lot of energy and labor. The surface of the product is not glossy, but matte. But the layer is so durable that it can be compared for corrosion resistance with stainless steel.

Hot and cold galvanizing has proven itself as a means for protecting metals. When zinc powder or vapor is applied to the surface of the product, using a high temperature, this process is called a diffusion coating. If zinc in the molten state is applied by a gun, like staining, then this is a shoop.

The process of applying zinc by means of a supersonic flow is a gas-dynamic coating. This method has increased adhesion and is very advantageous in this respect in comparison with others.

All these methods can easily be deployed on an industrial scale in a special production, but at home these processes will be very difficult to use, and in some cases simply impossible.

In order for the metal structure to meet the stated requirements and service life, it must be manufactured in accordance with the terms of the regulatory documentation. Clearly spelled out such requirements in the GOST.

Zinc plating is the most common and affordable way to protect iron from corrosion. It does not need special equipment and complex technological processes. The application of a zinc-containing composition is not more difficult than the treatment with paint. The content of the composition, which produces a cold galvanizing of the metal, is clearly regulated by GOST. It should have at least 94 percent of zinc.

What is this element?

Zinc is a chemical element belonging to a group of metals. It has a silvery white color. In its pure form has a rather fragile structure. It reacts with atmospheric air, namely with its constituents: carbon dioxide and oxygen. Due to this reaction, an oxide appears on the surface of the workpiece, which has a high bond strength and is not susceptible to dissolution.

The index of the electrochemical potential of zinc is halved compared to iron. Therefore, the compound pair is an anode in the form of zinc and a cathode-iron. When exposed to atmospheric moisture, zinc reacts with it, and carbonate is formed. It is he and his oxide that do not dissolve, but cover the product with a film.

Cold processing advantages

- The method of cold galvanizing has the main advantage - it is the absence of restrictions on the volume of the processed product.

- There is no need to dismantle the product and deliver it to the place of processing. Everything can be done stationary.

- The surface, galvanized in this way, does not interfere with the welded work. Welds can also be treated.

- Cold processing of metal structures with zinc occurs at a comfortable temperature - from -20 to + 40 degrees.

- The coating effectively protects against corrosion, and itself is not subject to serious deformation, since it is very elastic.

- Zinc plating allows to apply various coloring compounds to the surface.

- Works can be made independently, without the presence of special equipment and machinery.

- Cold galvanizing GOST 9.305-84 is clearly regulated by its composition and properties.

- Low cost.

Processing yourself

This coating, which protects the metal from corrosion, can be carried out at home, while observing caution. In addition to the cold method, it is possible to conduct galvanic treatment. But we must bear in mind that such an electrolyte is a highly poisonous substance. It must be handled carefully and carefully, it is imperative to have individual means of protection.

The construction market presents a wide range of tools that allow to carry out cold galvanizing of steel structures at home. Sometimes the content of the main element in them differs in a large range. Accordingly, the effectiveness will be lower, the lower its percentage.

Such compositions may have other disadvantages:

- the need for more thorough preparation of the part;

- poor adhesion to the metal, resulting in the formation of microcracks on the coating due to poor elasticity;

- Some manufacturers use only a specific solvent, which complicates the work;

- for the application of some a special apparatus is needed;

- Others simply are not provided for further painting.

"Galvanol"

Good characteristics and recommendations of consumers have such material as "Galvanol".

Its properties:

- has a high content of pure zinc powder, which reaches up to 96%;

- rapid drying, before applying the next layers you need to wait no more than half an hour;

- apply a similar cold galvanizing possible in any known way: brush, roller, immersion or spray gun;

- suitable for further painting with paint and varnish compositions, as well as polymer coatings;

- it is possible to apply rust without preliminary cleaning;

- does not lose its properties when applied at low temperatures (up to -35 degrees), as well as with humidity on the part;

- does not require a special solvent. Suitable universal, such as a solvent or xylene.

Consumers who conduct this composition cold galvanizing, reviews leave mostly positive. The metal is resistant to corrosion for several years.

How is it produced

Processing technology:

- Liquid zinc is well mixed, because it has a high density and stratifies. It is necessary to obtain a homogeneous liquid mass. From how well prepared the material for the protection of the product, depends on how long this anti-corrosion layer will last;

- clean the part mechanically;

- degrease the surface in any accessible way;

- Apply the next layer of the composition no later than in half an hour. Protection in two layers of zinc will last at least 10 years;

- the final layer, which will give the product a finished look, to apply better, after waiting a day.

When cold galvanizing is carried out, the technology must be observed. Only after this, the result of homework will not be different from the factory one.

Galvanic

Any galvanizing requires great accuracy and accuracy, especially at home. The source of current in this method can serve as a car battery or any charger with a power of up to 12 V.

As an electrolyte salt is suitable. But it is better, if it will be zinc. For its manufacture you need:

- Zinc sulphate - 200 g;

- magnesium or ammonium sulphate - 50 g;

- sodium acetate - 15 g;

- liter of water.

You can make salt by another method by placing zinc in a storage electrolyte and waiting for the reaction to finish, after which the acid will be converted to salt. Her concentration may be high. Then the salt is diluted with water.

Important! Electrolyte is a poison, it is necessary to work with it with extreme caution. The room during work should be well ventilated.

The ware for processing should be glass or from special plastic. To it the electrode from zinc is fastened. With a small amount of detail, a simple economic bank is suitable. The part must be well cleaned and degreased. It should be lowered into the prepared solution for no longer than 10 seconds. Then remove and rinse thoroughly with water. After that it is necessary to anodize the part. To do this, make a zinc electrode, connect to a power source. Formation of the zinc film occurs within 10-40 minutes.

Cost of cold-dip galvanizing compounds

In the "Barrier-zinc" content of active substance - 96%. The term of protection is from 10 to 50 years. It has a high economy, since it has a consumption of only 1 kg per 4 m ² . The cost is from 300 rubles per kilogram.

"Cinol" is a zinc-containing paint with 95% active substance content. The cost is from 340 rubles per kilogram.

Zinga - the composition of the Belgian production, which allows to carry out the zinc coating cold, having all the necessary properties to protect the metal from corrosion. The cost is from 576 rubles per kilogram.

Already mentioned by us "Galvanol" - the most popular tool among analogues. It has a 96% zinc content in the composition and all the necessary properties. The cost is from 390 rubles per kilogram.

"Cinotan" - contains only 85% of zinc. The cost is from 380 rubles per kilogram. Protective compounds based on zinc are available in a huge range. The price depends not only on the content of zinc, but also on the reputation of the issuing brand. Another composition that allows to carry out cold galvanizing is "Cinol".

How to choose the right one

When buying the necessary funds, it is better to pay attention in advance to its composition and declared properties. Color shades do not differ in variety, mostly it is matte gray. The application rate is practically the same - no more than 300 g / m ² . Therefore, these criteria can not be considered key when choosing, but what really matters is:

- life time;

- cost;

- Drying time;

- the content of zinc;

- shelf life;

- application conditions.

Conclusion

So, we found out how the cold galvanizing of metal structures is made. As you can see, this is a great way to protect the surface of the metal from the negative effects of corrosion, thereby increasing its service life.