Aluwindows24—Aluminum/Aluminium Window Coatings

Surface Coatings of Aluminum/Aluminium Profiles

The coating of aluminum/aluminium window profiles is carried out according to established international industry standards. Technical Guidelines for powder coating or anodizing window construction are, for example, determined by the Association of the Surface Finishing of Aluminum (VOA) and provided with corresponding seals of approval such as Qualicoat (aluminum/aluminium powder coating) or Qualanod (anodization/anodised). Organizations with international operations include the GSB, but which mainly focus on powder coatings for aluminum.

Aluminum/Aluminium Powder Coatings

Aluminium Window Coatings
The process of powder coating aluminum/aluminium takes place in four main steps. First, the aluminum/aluminium profiles are degreased and cleaned to eliminate grease or impurities and to provide an ideal primer for the finish coating. Second, the profiles are pre-treated and then undergo a type of chromate conversion coating. The natural surface of aluminum/aluminium is thus refined such that both an ordinary powder adhesion and corrosion protection is produced.
In the treatment of aluminum/aluminium windows for the sea-side construction, the alloy undergoes an even more specialized treatment. In this step, the surface of the aluminum/aluminium rods is pre-treated either by anodizing or with the use of a special kind of chromate. This gives the window a thicker corrosion-resistant layer between the metal surface and the actual powder.
The third step involves the actual powder coating of the aluminum/aluminium window profiles. The profiles are either run through a fully automated powder booth or coated by hand with a powder gun in small batches in a manual powder cell. The color grains are statically charged and become thereby perfectly distributed across the surfaces of the aluminum/aluminium profiles and sheets. Finally, in the fourth step, the aluminum/aluminium parts are then passed through a curing oven to obtain the final surface finish coating. The powder layer melts at a constant predetermined temperature to form a single integrated layer and is, so to speak, “brazened” into the surface of the aluminum/aluminium piece. The actual layer thickness for the range of architectural aluminum/aluminium and aluminum/aluminium window constructions usually ranges from 60-100 microns.

Aluminum/Aluminium Anodizing

Aluminium Window Anodization
The so-called ‘anodization’ of aluminum/aluminium windows makes use of a process in which the natural surface oxidation of aluminum is exploited. The aim is to build a decorative natural corrosion-resistant layer on the aluminum profiles through a controlled process, This layer has, in effect, similar properties to the natural oxidation layer of aluminum. Again, the process goes through four processing stages.
First, the degreasing of aluminum profiles and sheets provides for absolutely clean surfaces. In the second step, an ablation takes place, in which a combination of base and acid removes a few microns of aluminum/aluminium from the surface layer. This gives the profiles of the aluminum/aluminium window construction a uniform surface. In the third step, the anodic oxidation takes place through the influence of electric current and acid. One layer is built up on the aluminum/aluminium profiles, which depending on the duration and intensity of the current, amounts to 20-25 micrometers (windows and facade). This layer is ‘transparent’ and constitutes a change in the top layer of aluminum/aluminium. Then, in the fourth and final process, the so-called ‘sealing’ takes place. This step seals the surface of the aluminum/aluminium, which is still, at this point, porous. Now the surface of the aluminum/aluminium window profile is saturated and oxidized—in other words, will no longer corrode. In combination with anodizing, an organic coloring process can also take place (also known as C-31 to C35, for example, from brown tones to anodized black).

Other types of Surface Treatment

The surface coating of aluminum may be subject to additional mechanical or chemical treatments. Thus, options such as a stainless steel finish, wood structure, coloring or gloss are applied to the aluminum/aluminium window. These methods are usually carried out accompanied by an anodizing or coating.