Mass production of aluminum structures and parts due to the unique properties of this material.It has a minimum specific weight, resistant to many corrosive environments and is easily processed.But for long life products should be anodized aluminum.
Why is it necessary to
during any interaction of metal with the oxygen in the atmosphere, on the surface of the oxidation of the upper layer.This is called the formation of the oxide film, which prevents the spread of rust inside the metal.
Depending on the type of material the oxidation of the surface takes place in different ways.Iron and steel is practically not form an oxide film, but the precious metals (gold, silver, platinum) are protected against corrosion.Aluminium holds a middle position, so in need of artificial creation of the film.This is especially important if the manufacture of windows will apply a similar profile.Anodized aluminum is resistant to external weather factors which can cause corrosion and rapid loss of performance properties of the structure.
technology
To surface profile formed an effective protective film required anodized aluminum.The essence of the process lies in carrying molecules of another material that is more resistant to the effects of oxygen in the product structure.In addition, possible to artificially increase the oxide layer without the addition of other metals.
Whichever method you must fulfill the conditions of the process.It consists of the following stages:
- Preparatory.
- anodizing process.
- Securing layer.
For each of them selected the appropriate equipment and supplies.The result is supposed to be high-quality anodized aluminum.This will give an opportunity to use the profile for facade and window designs.
preparatory stage
surface of the product is thoroughly cleaned from dust, dirt and debris.If there are irregularities or mechanical damage, they are eliminated prior to anodization.This is followed by the oxide layer to remove old, otherwise it would prevent the formation of a uniform protective film.
After machining (sanding and degreasing), the profile must be placed in an alkaline solution.To properly anodized aluminum, you must first perform a "etch" the surface.Formation mikrokavern irregularities and increases the overall area of the protective layer.Further, the acid solution is performed lightening products.Upon completion of all phases of aluminum should be thoroughly rinsed.
Anodizing
After the preparatory phase can begin the process of anodizing.For this aluminum product is immersed in a special bath.The procedure is performed with the help of crane equipment (for large structures) or manually by means of wires.
O bath design should be discussed separately.It is a large thick-walled container made of stainless steel, in which are placed two cathode.Technology immersing the profile must be such that the electrolyte in the bath in contact with the whole area of the article.As such a liquid sulfuric acid is used, which places special demands on safety.If the product has a complicated configuration, it is better to use oxalic acid.
After the dive profile by electrolysis begins to form a protective layer.Its thickness depends on the composition of the electrolyte, temperature and current density.The higher the final score, the greater the oxide film formed on the surface.After completion of the layer thickness can vary from 2 to 7 microns, depending on the process parameters.
Securing
However, this stop anodized aluminum is still too early - is necessary to fix the resulting surface layer.It will pristavlyat a porous structure which quickly without treatment exfoliates.In addition, she has certain characteristics of hardness.
Securing can be achieved by placing the product in fresh water, brought to a boil state.Another technology the surface is treated with hot steam.In any case there is a rejection of the oxide film and its molecular compound with the aluminum surface.
If further profile will be painted, then you can not perform consolidation.With the technology of applying powder color schemes, the film will be protected as a result of heat treatment.
We found out what anodized aluminum.Such treatment of metal - a guarantee against rust on the surface of the product.Anodizing technology is constantly improving, and today you can do the painting of aluminum products with the help of the cathodic reaction.
