Metal products undergo corrosion during operation. As protection against this, metal galvanization is carried out. The technology of such processing at home is quite affordable. It is important to choose the right treatment option.
What is galvanizing
All metal elements are subjected to varying degrees of corrosive processes. You can’t do without it. And this process can only be delayed. It is for this purpose that zinc treatment is used. This choice of substance is not accidental. The choice is made based on the characteristics of two components: steel and zinc. Zinc has a more electronegative charge than steel. When a zinc coating is applied to metal products, a galvanic bond is formed between the metal and zinc. Due to this, zinc reacts under the influence of external environmental factors. Chemical reactions involving steel slow down. And this will continue until the zinc coating is completely destroyed.
In those cases when the zinc coating breaks up, the protection continues to work. This is due to the fact that zinc reacts with atmospheric oxygen. As a result of chemical processes, zinc hydroxide is formed. And this substance also has protective properties. Thus, galvanizing the metal continues to work.
Galvanizing Methods
Galvanizing metal products is the most popular way to combat corrosion. This is due to the ratio of a high test result and affordable cost. The following methods of galvanizing metal are used:
- cold
- hot;
- galvanic;
- thermal diffusion;
- gas thermal.
To choose the most suitable option for yourself, you must first analyze the conditions in which the product will be used in the future. The quality of galvanizing depends on the thickness of the coating, time and temperature of protection. Do-it-yourself galvanizing of metal is possible only in two ways: cold and galvanic. It is worth noting that the durability of the part processed in this way will depend on the operating conditions. The zinc layer is easily subjected to mechanical stress.
Hot way
Hot galvanizing metal is the most practical option. Chemical agents are used to treat the surface of the product. With their help, the metal is prepared for the main part of the process. It is because of this that an environmental problem arises. For the process using expanded zinc. The prepared product is simply immersed in a bath of molten zinc.
This process requires special equipment. Therefore, this method is not suitable for galvanizing metal at home.
Thermal diffusion method
Galvanizing a metal by this method involves the penetration of zinc atoms into the structure of a metal product with the formation of a zinc-iron alloy with a complex structure. The whole process takes place at very high temperatures. At a temperature of more than 2600 degrees, zinc goes into a gaseous state. The enclosed space where metal products are located is filled with zinc-containing powder. Suitable method for applying a layer whose thickness exceeds 15 microns. The resulting protective coating in terms of stability can be compared with a layer deposited by a hot method. Due to the need to create certain conditions, the method is not suitable for independent implementation.
Thermal method
In this method, zinc in powder form is sprayed with a stream of air over the surface of metal products. Before spraying, the substance melts due to high temperature and already in this state falls on the part. Galvanization of metal in a similar way is characteristic for those cases when metal products have large dimensions.
A feature of the method is that the protective layer has a large number of pores. To fill them, the product is covered with paints and varnishes. This layer of two materials is able to persist for 30 years. This method cannot be implemented at home.
Cold galvanizing at home
There is also galvanizing cold. Galvanizing a metal in this way involves applying zinc to a metal product in the form of paint. Manufacturers offer a wide selection of these tools. And the main indicators of the compositions (for example, the mass fraction of zinc in a substance) can differ greatly from each other. It becomes clear that the effect of processing will also be different.
Galvanizing agents have a number of features. Some require high quality product preparation. The second ones have low adhesive abilities, which is why after drying they begin to exfoliate. After application, the third ones are covered with a "cobweb" of cracks. Fourth can only work in conjunction with a particular type of solvent. Fifths require the application of special equipment.
This tool is a two-component. Therefore, before application, two substances (powder and binder) must be mixed together. Do this in a ratio of 3 to 1 or 1 to 1. The whole process should be carried out only in certain conditions. The air temperature should be positive and be in the range from 5 to 40 degrees. Furthermore, air humidity is from 30 to 98%. The room in which the process is carried out must have good ventilation. After work, it should be thoroughly ventilated. The product is applied in two layers at intervals of approximately 30 minutes. After a day, the product can be coated with paints and varnishes. When galvanizing, safety precautions must be observed. All work is carried out using personal protective equipment.
Galvanic method
Galvanization of metal at home can be carried out galvanically. To do this, the product must first be cleaned. After that, the part is lowered for several seconds (from 2 to 10) in sulfuric acid. After that, the product is washed in water. On this, preparation for anodizing is considered complete. For installation under galvanizing, it is necessary to choose dishes from inert materials, for example, glass. The container is selected in such a way that the part with the electrode fixed on it fits.
The current source will be a charger for 6-12 V and 2-6 A. Next, an electrolyte is prepared - a solution of any salt dissolved in water. In practice, it is better to take zinc salt. You can take diluted sulfuric acid (as in the battery) and add zinc there. As a result of a chemical reaction, the acid will turn into an insoluble salt and precipitate. And zinc will remain in solution. The precipitate must be removed simply by filtering the solution.
The zinc electrode is made from a piece of zinc, mounted on a copper wire. From the charger, the minus leads to the part, and the plus to zinc. Thus, the zinc electrode will dissolve, and all the zinc atoms will settle on the part.
Conclusion
Galvanizing metal at home is a very real process. For its implementation, you will need to purchase some materials. For example, zinc-based paint for the cold process or a piece of zinc for galvanic. By the way, zinc can be purchased at any scrap metal collection point.