Do-it-yourself galvanizing of metal: basic methods. Galvanic galvanizing Types of metal galvanizing

Galvanizing metal in a modern car is an opportunity to protect the body surface from corrosion. Galvanizing metal with your own hands at home is a completely feasible task.

There are certain types of metal that, when in contact with air, form a protective film on the surface. It protects the material from environmental influences and prevents corrosion. On metal, which is used to produce cars, the film is weak, so it is not able to protect the product from destruction.

Industrial processing methods

You can create additional protection against corrosion in several ways, for example, by coating products with tin or zinc. Galvanizing a material is a fairly simple task and can be easily done with your own hands. Treatment of parts, for example for a car, will protect the surface of the products from direct contact with air, which prevents oxidation of the surface. Metal processing with zinc is possible in several ways:

Hot and cold galvanizing.
Galvanic.
Gas-thermal.
Thermal diffusion.

When processing a material using one of these methods, the duration and temperature of the process affect the thickness of the protective surface layer formed.

Hot-dip galvanizing technology

This method of metal processing is one of the most effective. Zinc remains on the surface for a long time and reliably protects against corrosion. The disadvantage of this treatment is that this technology is harmful to the environment since the material is processed chemically. Hot galvanizing of metal consists of several subsequent processes:

Preparation. The surface of the parts must be degreased, and then the metal must be etched.
Treatment. After preparation, the machine part must be washed and dried.
Galvanizing. The product is lowered into a tank containing molten zinc.

This processing method, despite its effectiveness, has significant disadvantages:

Cold galvanizing technology

Galvanizing car parts using this method is quite simple. Surface treatment is carried out using a special paint containing zinc. The metal surface is painted with zinc paint using the usual painting method: with a brush, roller or spray gun.

Using zinc-containing powder paint and a spray gun makes galvanizing a vehicle easier. The spray gun allows you to completely treat the entire surface of the body, including hard-to-reach places. This method is most often used to apply a protective coating to products that are difficult to hot process. The car body is just such a case. This method is also used for processing previously galvanized metal.

Galvanizing technology

Galvanic deposition of zinc involves processing the metal using electrochemical action. Processing with this method allows you to achieve a smooth and thin protective layer on the surface of the product. In order for the zinc to adhere to the surface, for example, of a car body, the products are placed in a special container in which a zinc plate is located. After this, electricity is supplied to the container, as a result of which the zinc from the surface of the plate is transferred to the machine body, forming a protective layer.

The disadvantages of this method include its high cost compared to other methods of applying a protective layer. In addition, such treatment is dirty and wastewater treatment also requires high costs.

Gas-thermal galvanizing method

This method of applying protective coating is excellent for the body of large vehicles that cannot be treated using conventional methods.

Zinc is applied to the surface of the car body using a strong gas stream. The use of this method requires subsequent application of paint, since the zinc does not spread evenly on the surface and does not fill the entire surface of the car. But despite this, this method of creating protection provides reliable coverage. It protects the car both from air exposure and provides reliable protection against corrosion in wet conditions.

Thermal diffusion galvanizing method

This method involves the use of high temperatures. At a temperature of approximately 2.6 thousand degrees, zinc breaks down into atoms, which are deposited on machine parts. The advantage of this method is that it can be used to achieve a thick protective layer.

The process of applying protective material to the car body is carried out in a special closed chamber. Powdered zinc is applied to the product, after which the entire chamber is heated. This can only be done in an industrial environment, so you won’t be able to apply zinc yourself at home.

The use of this method is safe for the environment and allows for galvanizing of excellent quality. Zinc is applied to the surface of the machine in a thick layer, which will reliably protect metal products from corrosion. The method has only one drawback - its high price.

Galvanizing at home

Galvanic method

Electroplating of a protective layer, for example, on car parts, can be done at home. To do this, you will need a car battery or power supply with characteristics of 2–6A and a voltage of 6 to 12 volts. To perform galvanic formation of a protective layer, you need to have an electrolyte. To do this, you need to make a solution using the following ingredients:

Having prepared such a solution at home, you can galvanize the metal parts of the machine. Instead of the described solution, liquid from your car battery will also work. An ordinary glass jar is suitable as a container for the composition. The galvanizing process at home using the galvanic method looks like this:

Cleaning and degreasing car parts.
Immerse the workpiece in sulfuric acid for a few seconds.
After repeated washing, the material is placed in a container for subsequent galvanizing.
Secure the positive contact from the battery or power supply to a zinc plate.
The negative contact should be attached to the workpiece.
After this, place the zinc plate and the car part in a container with the solution and leave for 30 - 40 minutes.

When carrying out this operation at home, you should keep the windows open in the room, and also use special clothing and gloves. Using this set of devices, you can galvanize small products or car parts with your own hands. The method does not require much expenditure from you and is carried out quickly.

Cold galvanizing method

Galvanizing of machine parts can also be done using the cold galvanizing method. For this method, you need to purchase special paint containing zinc. It is two-component, so before the galvanizing process, the paint components must be mixed together. A set of zinc powder and a binder must be mixed in a ratio of 3 to 1 or 1 to 1. After mixing the paint, at positive air temperatures, apply the composition to the machine part. The cold method is very simple and easiest to do at home.

Despite the fact that galvanizing metal in an industrial environment is a complex process, you can galvanize products at home using simple methods.

Coating metal products with zinc is the simplest, most common and cheapest method of corrosion protection. Galvanizing at home is characterized by easy and affordable technology.

1 Galvanizing as a method of corrosion protection of metals

In world practice, the most widely used anti-corrosion metal coatings are zinc. . This is due to the relatively low cost of zinc and the fairly high efficiency of the resulting protection from the external environment. At the same time, the coating process, called galvanizing, is characterized by low costs. In the atmosphere, zinc interacts with oxygen, as a result of which a thin oxide film is formed on its surface, protecting the protected metal from the harmful effects of the external environment. There are several ways to galvanize metal parts:

hot;
gas-thermal spraying;
thermal diffusion;
cold;
galvanic.

The galvanizing method is chosen based on the conditions of subsequent use of the product and the desired properties of the protective layer. Several types of coating can be used for one part. In order for the result to be of high quality in all cases, it is important to correctly select the thickness of the zinc coating, depending on the temperature and time of the process. It should be remembered that the galvanized metal part should not be subjected to any mechanical stress.

2 Technologies of various galvanizing methods

Hot – coatings are applied by immersion in a container with molten zinc, the temperature of which is maintained in the range of 460–4800 °C. Hot-dip galvanized coatings are among the best in terms of durability and quality, and are in 2nd place in terms of production volume. The technological process is energy-consuming and complex in terms of ensuring environmental safety, which is due to the use of chemical surface preparation methods and the presence of molten zinc.

Gas-thermal spraying - powdered or wire zinc is melted and sprayed in a gas stream onto the metal of the workpiece. This method is optimal for anti-corrosion protection of large-sized metal structures that do not fit into a galvanic or molten zinc bath. Particles of molten zinc strike the surface of the product and, when deformed, form a porous (“scaly”) coating, which, as a rule, requires treatment with a filler (paint and varnish material). The combined coating does not lose its protective qualities in various environments (atmosphere, sea and fresh water) for 30 years or more.

Thermal diffusion (sherardization) - zinc coating is obtained due to the penetration of zinc atoms into the iron substrate with the formation of an iron-zinc alloy having a complex structure. The effect is achieved due to the fact that zinc atoms pass into the vapor phase at temperatures above 2600 °C. The process is carried out in a closed volume of muffles or retorts filled with workpieces and a powder zinc-containing mixture. The technology is used when it is necessary to obtain a zinc layer thicker than 15 microns (usually 25–110 microns). The method is environmentally friendly. The coating is non-porous, with high adhesion, the protective ability is 3–5 times higher than that obtained by galvanic method, and is comparable to the resistance of hot-dip zinc.

Galvanic – provides the creation of a very smooth and precise coating, which is applied by electrochemical action. The method is applicable not only to electrically conductive materials, but also to non-electrically conductive ones. The resulting coating is uniform, precise in size, decorative in appearance, shiny, thickness, as a rule, does not exceed 20–30 microns. Technology - zinc plates and the structure being processed are immersed in a reservoir of electrolyte and then connected to a direct current source. During the electrolysis process, the zinc anode dissolves and its molecules settle on the surface of the product. The electrochemical method is associated with the generation of hazardous waste.

Cold – painting of metal products with primers saturated with highly dispersed powdered zinc (the finished coating contains 89–93% zinc). The method is highly technological, is the simplest, and is currently widespread. It is very effective for products and structures that cannot be processed in any other way - fixed transmission lines, pipes, elements of oil equipment, railway tracks, road fences, furniture fittings and other stationary, immovable, hard-to-reach objects. A “cold” coating can last 3–4 times longer than a “hot” one. Disadvantages - relatively low resistance to various mechanical influences and high requirements for sanitary and hygienic working conditions for painters due to the use of organic solvents.

All of the above methods are used on an industrial scale. The last 2 can be implemented independently, observing the necessary security measures.

3 Galvanic galvanizing at home

Galvanizing at home is a procedure that requires great precision and accuracy. . The current source can be a 2–6 A, 6–12 V charger or a car battery. To make an electrolyte, theoretically, you can use any salt that can dissolve in water. However, in practice it is easier to make a solution of zinc salt. Its composition:

200 g of zinc sulfate;
50 g ammonium or magnesium sulfate;
15 g sodium acetate;
1 liter of water.

You can use battery electrolyte (an aqueous solution of sulfuric acid), in which you need to place zinc. When the reaction stops, the acid is converted to a salt, leaving the zinc behind. If the acid solution is overly concentrated, a precipitate (crystalline zinc sulfate) will appear at the bottom. In this case, the solution is slightly diluted with water. It is important to remember that electrolyte is a dangerous poison that should be handled with extreme caution and in protective clothing. The room where work is carried out must be well ventilated.

Select dishes made of vinyl plastic or glass. When the part is small, even a liter jar will do. Provides the possibility of attaching a product and a zinc electrode to it. The electrolyte is filtered and poured into a container. The part intended for galvanizing must be thoroughly cleaned and degreased. This must be done as best as possible so that the zinc lays evenly and firmly. Then the part is immersed in the solution for 2–10 seconds, after which it is immediately washed under running water. This procedure is called chemical activation. After this, they begin to anodize the product.

A zinc electrode is made from a piece of zinc by drilling a hole in it and hanging it on a copper wire. The electrode must meet the following requirements:

the surface area is comparable to the area of the product;
The shape is flat and convenient for placement in a container.

Copper wires are used to connect to the power source. The minus is brought to the part, and the plus is brought to the zinc electrode, which “dissolves”, and a layer of zinc is formed on the product. Processing time is 10–40 minutes.

4 Parameters of home galvanizing

The most difficult part of the job is selecting the galvanizing mode. The quality of the part's coating depends on it. Either zinc powder will settle on it, which can be easily removed with a rag, or a durable layer that will last a long time.

Factors that determine the quality factor of the coating:

Current density is the amount of current divided by the surface area of the product. There should be 0.5–10 A per 1 square decimeter (optimally 1.5 A/dm2). The voltage regulator ensures that the reaction is not too violent. If bubbles come from the surface of the product excessively, the coating will be uneven and weak.
The electrolyte temperature should be room temperature (18–25 °C).
Electrolyte density varies over a wide range (from zero to the solubility of zinc salts).
Product geometry - for a part with a complex shape, depending on the distance of its various fragments from the zinc electrode, there may be a significant difference in the thickness of the coating in different areas (weak coating in the recesses, and build-ups form on the sharp edge).

Based on what was described above, it is advisable to increase the distance to the electrode, use 2 zinc anodes, twist the part, and experiment. Galvanizing can be carried out in 2 or 3 layers with the concomitant removal of formed growths.

5 Do-it-yourself cold galvanizing

Cold galvanizing is the application of a coating in the form of paint. This formulation contains the basic meaning of the material used - this is not paint containing zinc, but this metal in the form of paint.

For cold galvanizing, you can find a large variety of materials from various manufacturers on the market. For many compositions, sometimes the main characteristics (zinc content, for example) vary widely. Accordingly, the effectiveness of their use may also change. Some compositions are very demanding on the quality of preparation of the metal surface, others have insufficient adhesion strength to the part and they peel off easily, some have low elasticity and are covered with a web of cracks, there are those that require a proprietary solvent, special equipment is required to apply a number of materials, There are some that are not compatible with finishing coatings.

All materials offered include two components supplied in separate packages - zinc powder and a liquid binder component. Before use, both substances are mixed according to the standards specified in the paint documents. The proportions “powder” - “binder” range from 1:1 to 3:1. The product is applied at a temperature of 5–40 °C and air humidity of 30–98%. During and after work, the room is thoroughly ventilated. Personal protective equipment must be used.

content of fine chemically pure zinc powder 96%;
dries quickly - you need to wait 30 minutes before applying the next layer;
can be applied in any way (by immersion, roller, brush, spray gun, etc.);
can be painted with any paint materials, polymer coatings can be applied;
application on rust is acceptable;
it is possible to apply to wet metal even at negative temperatures (up to -35 ° C);
soluble in available solvents (xylene, solvent).

Galvanol it is so technologically advanced and easy to apply that it allows you to highly effectively protect cast iron, steel and iron even in ordinary home conditions.

6 Basic requirements for cold galvanizing at home

An important component of cold galvanizing of metal is that liquid zinc is pre-mixed. Due to their high density, the compositions are highly stratified and immediately before use they must be thoroughly mixed until a homogeneous mass and liquid is obtained. In addition, the better the metal is prepared for coating, the more durable the protective zinc layer will be. Therefore, it is best to mechanically clean the part followed by degreasing.

Galvanization applied to such a product in 2 layers will last at least 10 years. The next layer is done just 30 minutes after the previous one. Before applying topcoats and paintwork materials, it is necessary to wait 24 hours (so that the remaining solvent completely evaporates). Cold galvanizing, carried out with your own hands in compliance with the technology and instructions for using the composition, is not inferior in quality and reliability to the factory version.

Coating metal products with zinc is the simplest, most common and cheapest method of corrosion protection. Galvanizing at home is characterized by easy and affordable technology.

1 Galvanizing as a method of corrosion protection of metals

hot;
gas-thermal spraying;
thermal diffusion;
cold;
galvanic.

2 Technologies of various galvanizing methods

Thermal diffusion(sherardization) - zinc coating is obtained due to the penetration of zinc atoms into the iron substrate with the formation of an iron-zinc alloy having a complex structure. The effect is achieved due to the fact that zinc atoms pass into the vapor phase at temperatures above 2600 °C. The process is carried out in a closed volume of muffles or retorts filled with workpieces and a powder zinc-containing mixture. The technology is used when it is necessary to obtain a zinc layer thicker than 15 microns (usually 25–110 microns). The method is environmentally friendly. The coating is non-porous, with high adhesion, the protective ability is 3–5 times higher than that obtained by galvanic method, and is comparable to the resistance of hot-dip zinc.

Galvanic– provides the creation of a very smooth and precise coating, which is applied by electrochemical action. The method is applicable not only to electrically conductive materials, but also to non-electrically conductive ones. The resulting coating is uniform, precise in size, decorative in appearance, shiny, thickness, as a rule, does not exceed 20–30 microns. Technology - zinc plates and the structure being processed are immersed in a reservoir of electrolyte and then connected to a direct current source. During the electrolysis process, the zinc anode dissolves and its molecules settle on the surface of the product. The electrochemical method is associated with the generation of hazardous waste.

All of the above methods are used on an industrial scale. The last 2 can be implemented independently, observing the necessary security measures.

3 Galvanic galvanizing at home

200 g of zinc sulfate;
50 g ammonium or magnesium sulfate;
15 g sodium acetate;
1 liter of water.

A zinc electrode is made from a piece of zinc by drilling a hole in it and hanging it on a copper wire. The electrode must meet the following requirements:

the surface area is comparable to the area of the product;
The shape is flat and convenient for placement in a container.

4 Parameters of home galvanizing

The most difficult part of the job is selecting the galvanizing mode. The quality of the part's coating depends on it. Either zinc powder will settle on it, which can be easily removed with a rag, or a durable layer that will last a long time.

Factors that determine the quality factor of the coating:

Current density is the amount of current divided by the surface area of the product. There should be 0.5–10 A per 1 square decimeter (optimally 1.5 A/dm2). The voltage regulator ensures that the reaction is not too violent. If bubbles come from the surface of the product excessively, the coating will be uneven and weak.
The electrolyte temperature should be room temperature (18–25 °C).
Electrolyte density varies over a wide range (from zero to the solubility of zinc salts).
Product geometry - for a part with a complex shape, depending on the distance of its various fragments from the zinc electrode, there may be a significant difference in the thickness of the coating in different areas (weak coating in the recesses, and build-ups form on the sharp edge).

5 Do-it-yourself cold galvanizing

content of fine chemically pure zinc powder 96%;
dries quickly - you need to wait 30 minutes before applying the next layer;
can be applied in any way (by immersion, roller, brush, spray gun, etc.);
can be painted with any paint materials, polymer coatings can be applied;
application on rust is acceptable;
it is possible to apply to wet metal even at negative temperatures (up to -35 ° C);
soluble in available solvents (xylene, solvent).

Many methods and methods have been created to protect metal from corrosion. Their essence lies in the fact that a special substance is applied to the surface of the metal. At the final stage, a thin film is formed. It prevents moisture, oxygen, and aggressive substances from entering the surface. Among these methods, they are distinguished. It is the most effective.

General information

As mentioned earlier, galvanizing a metal is the process of applying a special substance to the surface of a product.

Such solutions are created on the basis of zinc, which is the most suitable starting material. It prevents corrosion and also protects the surface from aggressive substances. The processed sheet has a number of advantages:

the strength of the product increases;
resistance to different temperatures;
not exposed to aggressive substances;
the service life of the product increases;
the product is not subject to oxidation.

Technological basis

Galvanizing of metal is a popular procedure all over the world. This process involves applying a special zinc solution to the steel surface. After this, a thin film is formed, which performs protective functions, that is, it prevents corrosion. Corrosion changes the structure of the metal and renders the product unusable.

How does it rust?

As mentioned earlier, products are affected by moisture, as well as oxygen and aggressive substances.

Their molecules enter the deep structure of the metal, which leads to the appearance of rust. As a result, holes appear on the surface. This process can take a long time. To slow down the oxidation process, use a zinc solution.

Stages

Galvanizing of metal involves covering various types of products with a protective zinc film. To perform this procedure, you must have special equipment. Each element of the device should not be exposed to moisture or aggressive substances. The galvanizing process is divided into the following stages:

Preparatory. First of all, you need to put the product in order. Its surface must be cleaned of various substances and then degreased. Next comes the etching process. The metal product is lowered into a container with an acidic medium. As a rule, a solution of sulfuric acid is used. Due to metal etching, an oxide film appears on the surface. This means that the zinc solution will last longer. At the final stage, acid residues are removed from the product and dried.
Galvanizing process. This stage consists of applying a solution to the prepared surface. To make it, you need to melt zinc in a special bath under high temperature. When the solution is ready, a metal product is immersed in the bath and left for several minutes.
Drying the product. The galvanized product is dried at room temperature.

The process of galvanizing metal products occurs in special baths.

If necessary, they are equipped with sockets. Despite their significant volumes, they also process a large number of small items. Thus, equipment for galvanizing metal and hardware can have not only small, but also large sizes.

Basic processing methods

The most popular way to protect metal products from corrosion is galvanizing. There are different ways to do this process. Each of them is used for a specific type of metal. Some species may react with zinc. There are four types of processing: hot, cold, thermal diffusion, galvanic. Let's look at each type in more detail.

Hot

Coating products in this way is popular in many countries. Its main positive properties are high quality and long service life. Therefore, this method has become one of the best. There are also a number of negative properties. First of all, the method is not environmentally friendly, since many chemicals are used at the preparation and galvanizing stage. In addition, there is a significant difficulty in hot working. It is necessary to maintain the temperature of zinc in the range from 500 to 5000ºС. Maintaining this level of heating requires a lot of electricity. metal at home is a rather complicated process.

Technologically, the process is divided into two stages. This is the preparation and galvanizing of metal. At the first stage, they prepare the metal product. Its surface must be degreased and cleared of debris. After this, etching, washing and drying occurs.

These operations are prescribed in regulatory documentation.

To coat a part with zinc, you need to immerse it in a special bath. It contains a special solution that prevents corrosion. Methods for fixing metal during hot-dip galvanizing can be different. They depend on the type and shape of the product. This technology is used in many industries. For example, for the production of galvanized wire, pipes, etc.

After applying the hot method to them, the products have a long service life, that is, they are reliably protected from corrosion. The only difficulty is the baths. To process large parts, it is necessary to find a bath of appropriate volumes, which is quite difficult. This feature affects costs. Where is hot galvanizing of metal performed? Kursk, Yaroslavl - this is just a small list of cities where various companies offer this service. Often they work with large volumes.

This interaction is affected by the presence of various debris or other films on the surface. Therefore, before starting the procedure, you should do some cleaning. In mass production, it is difficult to monitor this, so galvanizing may be of poor quality.

The galvanic method is based on immersing a metal product in a bath where a current source is connected to the part. In this case, the process of electrolysis occurs. It is exposed to zinc, which coats the metal part.

pros

The main positive quality is the appearance of the product - the surface is smooth and shiny. However, there is also a significant drawback. Before draining the solution that was in the bathroom, it is necessary to clean it of zinc. This method generates a large amount of waste that is harmful to the environment. Therefore, it is necessary to purchase special expensive equipment. It will release zinc from the solution. Therefore, this method is one of the most expensive.

How to galvanize metal at home?

This procedure is used by many craftsmen when it is necessary to process small parts. First you need to find a suitable container and make an electrolyte. The procedure is carried out in a well-ventilated area and in protective clothing, since electrolyte particles can be harmful to humans. If they come into contact with the skin, a chemical burn is possible. To prepare, take water, zinc sulphide, magnesium and vinegar. The finished concentrate must be filtered. Next, the metal part is lowered into the container and the anode product is prepared. A copper wire is attached to a small piece of zinc and connected to the electrical network. The product is lowered into the electrolyte and the processing process begins. After this, the metal part is dried. Galvanizing metal at home is quite easy to do.

Features of the cold method

Over the past few years, this method has become widespread. Its essence lies in the fact that a metal product is painted with special substances that contain zinc. This method does not require any special skills. However, there are also disadvantages: finished galvanized products are subject to mechanical stress. In addition, it is necessary to constantly monitor the technical personnel who prepare the solution and perform the work. As mentioned earlier, this method is quite simple. Therefore, equipment for cold galvanizing of metal is not required. Work must be carried out in accordance with sanitary and hygienic rules. Using this method, pipes are processed, as well as products that are in a fixed version. To do this, you need to prepare a solution and apply it to the product using a brush or roller. The only metal equipment used is a spray gun. It helps to reach inaccessible places and paint evenly and efficiently. Among the disadvantages, many users note low reliability.

Thermal diffusion galvanizing technology

This method has been used for a long time, but it is still popular today.

It was first used in England at the end of the 19th century. The invention became famous thanks to the famous scientist Sherard. However, this method was quickly forgotten, replaced by another. Its revival occurred at the end of the twentieth century. The technology of the thermal diffusion method is that the surface of a metal product is treated with zinc in a vapor state. To do this, it must be heated to 2500ºС. The process is carried out in a closed container in the presence of a zinc-containing mixture and metal elements. The technology for carrying out this procedure is determined not only by domestic, but also by imported regulatory documents.

Thermal diffusion galvanizing is performed when it is necessary to achieve a thickness of 20 microns. The technological process is similar to the hot galvanizing method. However, there are also differences. The prepared product is lowered into a drum oven, where processing occurs due to rotating forces. This process is completed within 3 hours of operation of this equipment. It is used to paint various small parts, such as washers and screws.

Unlike the hot method, zinc dusting occurs evenly over the entire surface.

Conclusion

This process helps protect various metal parts from corrosion, moisture, and aggressive substances. There are 4 technological types of galvanizing. Each of them has its own characteristics and is suitable for a specific type of metal. Incompatibility of such components will lead to poor-quality painting and, as a result, to a decrease in the strength of the finished product. Galvanizing occurs in special baths or drum furnaces. However, the process can also be done at home. To do this you need to purchase consumables. The work is carried out in a ventilated area in special protective clothing, since some components cause harm to the human body.

Galvanizing a metal is one of the most common methods of protecting it from the appearance and development of corrosion, increasing its performance qualities and significantly increasing its service life.

Galvanizing refers to the application of a coating consisting of 95 percent zinc to the surface of a metal. Galvanizing is performed in various ways, each technology has its own advantages and disadvantages.

General information and purpose

Steel products are susceptible to corrosion, especially when used in conditions of high humidity. The galvanized steel part is reliably protected from corrosion. The coating together with the metal forms a galvanic couple, where zinc has a higher degree of electronegative charge compared to steel. Accordingly, zinc undergoes corrosion, and steel reacts practically without any reaction. The anti-corrosion protection of the metal will last until the zinc coating is destroyed.

There are several galvanizing technologies. Some technologies allow do-it-yourself galvanizing with obtaining an acceptable result.

There are the following methods of galvanizing metal:

cold;
hot;
galvanic;
thermal diffusion;
gas-thermal.

You need to choose one or another method for galvanizing steel parts or structures depending on the conditions of use and the characteristics of the protective layer. Regardless of the galvanizing technology used, it is necessary to determine the thickness of the protective layer. It depends on parameters such as the period of exposure of the working environment to the metal and the processing temperature.

When using steel structures on the surface of which a layer of zinc is applied, you must remember that they cannot be subjected to strong mechanical stress, since the protective metal coating is highly brittle and can be destroyed.

Let's look at different types of metal galvanizing.

Hot galvanizing method

Hot galvanizing of metal allows us to achieve maximum quality of products and ensure their durability. This method has a key drawback - its implementation involves the use of chemical reagents to treat the surface, and the procedure is performed in molten zinc.

The hot galvanizing method of steel includes preparing the surface of the product and the actual procedure of coating the metal with zinc.

Steps to prepare the surface to be treated:

cleansing;
degreasing;
application of acid solutions;
washing and fluxing;
drying the surface.

When the surface goes through all the stages of preparation and dries, the product is placed in a special bath with molten zinc. A thin layer of zinc and iron is formed on the surface of the steel, which reliably provides anti-corrosion protection. When the product is removed from the bath, it is blown with compressed air to dry it and remove excess zinc from the surface.

The disadvantage of this method is that the dimensions of the products are limited by the dimensions of the bath with molten zinc. This method is practiced at large production facilities when working with power transmission poles, scaffolding or lighting masts.

The method involves a lot of labor and the use of complex equipment, so it is not suitable for home use.

This method of processing metal with zinc has gained wide popularity in recent years. The main reason is the high manufacturability and simplicity of the method, coupled with the high protective properties of the layer on the metal surface. The option is suitable for galvanizing metal with your own hands, since no special equipment is required for the work.

Cold galvanizing technology involves applying a zinc-containing mixture, for example, zinconol, to the surface of the product. It must be applied with a roller or brush. If you need to cover structures of complex shapes or hard-to-reach places, you can use a spray gun. Thanks to special compounds, a protective layer is formed on the surface, consisting of more than 90 percent zinc.

This galvanizing method is the only one acceptable for providing anti-corrosion protection to structures that cannot be galvanized in any other way. For example:

installed pipes;
elements of railway tracks;
power line supports and other structures in a stationary or mounted version.

Zinconol and other cold galvanizing compounds are used during repairs if there is a need to restore the damaged zinc layer on metal structures. For example, this is relevant for the purpose of restoring the galvanization of a car body.

Cold galvanizing of steel products is carried out over a wide temperature range; the resulting coating has high protection, elasticity, and resistance to mechanical stress and temperature changes.

Cold galvanizing has its disadvantages. For example, the formed coating does not have high enough resistance to mechanical stress; safety precautions must also be strictly observed if the procedure involves the use of organic solvents.

Galvanic galvanizing method

During galvanic galvanizing, an electrochemical effect is applied to the surface of the product. The resulting coatings have high thickness accuracy and exceptional smoothness. Also, a protective layer with a thickness of about 20–30 microns is formed on the metal surface.

With the help of such galvanizing, the thickness of the protective layer can be adjusted, while the layer is uniform and has high decorative qualities. Metal and zinc are combined at the molecular level during galvanizing; the coating has high adhesion to the base material. The degree of adhesion is affected by the presence of oxide and fatty films on the surface, which are almost impossible to remove.

Galvanic galvanizing is carried out as follows:

the structure and zinc plates are placed in an electrolytic solution, then the positive and negative contacts of the current source are connected to the wall of the bath and the plates;
due to the potential difference, the plates dissolve in the electrolyte, and zinc molecules settle on the surface of the product and form a uniform protective layer.

The key advantage of this method is that in this way a protective layer is formed on the surface, which has special decorative characteristics. The thickness of the layer can be adjusted. But the method also has its drawbacks. In particular, this is a high cost.

Thermal diffusion galvanizing technology

This technology is also called sherardization. It was developed in the 20s of the last century, but for a long time it was not widely used. It was only in the 90s that the method gained popularity.

The essence of the method is that the part, together with a dry zinc-based mixture, is placed in a sealed container, where a temperature of about 2600 degrees is created. At this temperature, zinc goes into a gaseous state, and accordingly, the process of diffuse penetration of zinc atoms into the surface layer of the product is accelerated. This galvanizing technology is used in cases where it is necessary to form a protective layer with a thickness of 15 microns on the metal surface.

The preparation of metal products for thermal diffusion coating with zinc does not differ from the hot method. Advantages of this method:

Disadvantages of the thermal diffusion method:

the finished coating does not have a metallic sheen and has a dirty gray tint;
low productivity;
zinc dust in the air during work can harm the body;
The zinc coating is not uniform in thickness.

Thermal spraying

The gas-thermal galvanizing method is suitable for coating a three-dimensional part or sheet of metal with zinc. Its essence is that zinc, in the form of a dry mixture or wire, is sprayed in a gaseous environment onto the surface of the workpiece. The technology is used to apply a layer of zinc to large-sized products that cannot be processed otherwise.

Zinc plating process:

The parameters of zinc coatings applied by the methods listed above are established by the relevant GOST.

Do-it-yourself galvanizing

As already mentioned, some types of galvanizing can be done independently at home. This applies to cold galvanizing technology or the electrochemical method.

To perform galvanizing yourself using an electrical method, you need to carefully prepare the surface of the workpiece. Preparation includes:

cleaning;
degreasing;
acid pickling;
rinsing under running water.

You can make an apparatus for galvanic galvanizing yourself based on a direct current source with a voltage of 6-12 V at a current strength of 2-6 A and a capacitance based on a dielectric device and a device for fixing the product and electrode. Any salt solution containing zinc acts as an electrolyte. To prepare the solution, zinc is placed in a battery electrolyzer and dissolved in it. Before use, the composition is filtered.

When performing galvanizing with your own hands, you need to take into account that the quality and thickness of the coating are influenced by the following factors:

Galvanizing metals allows you to slow down the process of corrosion of products. Galvanizing methods depend on the operating conditions of the products. You can galvanize materials at home.