Anodized aluminium. Special coating for material

2024 Author: Howard Calhoun | [email protected]. Last modified: 2024-01-02 13:48

The use of aluminum profiles for finishing some sections of the house, as well as its use for interior manufacturing, has been going on for quite some time. The metal itself is characterized by high ductility, good appearance and light weight, but it oxidizes very quickly and becomes covered with a gray coating if it interacts with oxygen.

What is anodized aluminum?

In order to preserve the bright luster of metal products, a special coating had to be used. Due to the application of an additional coating, the appearance has not changed much, but at the same time, such troubles as corrosion can be forgotten for a very long time.

In order to understand what anodized aluminum is, it is necessary to find out how the metal is covered with a protective film. Usually, metals are protected from the effects of the external environment with the help of various protectors and other things. In this case, the protective film is ordinary, but already oxidized aluminum, which has the following chemical formula: Al₂O_{3. However, it should be noted that in this casewill be presented not as a soft and thin amorphous film, but as a crystalline structure, which is very similar to spinel, for example.}

What characterizes the film?

It turns out that anodized aluminum is covered with a film of already oxidized material. This protective agent is characterized by the following properties:

• microcrystalline type structure;
• the base is presented in the form of an ultra-dense film, and the outer layer is a film with a large number of pores;
• The adhesion of this oxidized compound to aluminum is very strong.

The last point is very important. It means that anodized aluminum will be able to maintain its protective layer under any load for 40 years or more. This greatly distinguishes this composition from such as paint or nickel coating, which peels off aluminum simply over time.

It can be added that the result will depend on the selected technical layer. That is, the properties of the film can change. It can be ultra-thin and be only 10-25 microns across the thickness of its structure. In this case, it can not even be seen with the naked eye. However, even such a layer is able to protect the metal from any aggressive influences and at the same time transmit up to 95% of the light.

Anodizing technology

The uniform color of anodized aluminum means that the material has the thinnest protective layer. The process of obtaining such a protective layer is based on the fact thatanodic oxidation of aluminum occurs in the electrolyte solution. Depending on what kind of anodized aluminum you need to get at the end, three types of electrolytes are used:

• treatment with very low current in the presence of constant voltage and weak acid type electrolyte;
• this type of coating can be applied under the influence of a dichromate acid electrolyte;
• Oxidation of a substance can also take place in an alkaline electrolyte.

In order to change the properties of the final film, parameters such as acidity, bath temperature, and operating voltage at the anode and cathode can be changed.

Anodized aluminum cookware

It should be said right away that only three types of technological process are used for the production of dishes: stamping, casting and forging. In the presence of aluminum with such a crystal structure, all three types can be used. All manufacturers of kitchen appliances and utensils claim that the use of this material allows you to create things of a new generation. The main reason why such a light and convenient metal could not be used before was the oxidation process. The moment of contact with food worsened their quality, and they could not be consumed. Anodizing solved this problem.

Aluminum sheet

In addition to dishes and other parts, anodized aluminum sheets are also produced. In addition to the fact that such a layer helpsget rid of corrosion, it also protects the metal from fading. Another property is increased wear resistance. Thanks to this, it was possible to improve the quality of all duralumin parts. This is very important in the manufacture of, for example, dashboards. The parameters of the produced sheets are as follows:

• sheet thickness is 0.5-2mm;
• sheet dimensions - 500 × 600 mm;
• minimum number of sheets per batch - 1.

As for the use of anodized aluminum, immediately after its invention, it was widely used for the production of aluminum (duralumin) parts for aircraft. Another use for this type of aluminum is as a protective layer for other elements, as well as a base for paint application. It is also worth adding that such a protective layer is much harder than aluminum itself. This significantly increases the wear resistance of all elements. The protective shell helps to make aluminum a good electrical insulating material, however, the possibility of a small local breakdown is still present, and therefore this somewhat limits its use as an insulator.