Colors aluminum - anodized process :: Reynalco

Technical area > Colors aluminum - anodized process


The anodized term for this type of protective treatment, word comes from the anode. An anode is that the positive pole of an electrolyte.
Contrary to what most people think metal aluminum as it is susceptible to oxidation by oxygen present in the air.
What is then made to take advantage of these qualities of aluminum and increase its hardness is anodizarlo. You could say that it is a uniform surface layer of aluminum profile controlled artificial oxidation and, through the electrolysis.

Before that electrolysis, aluminum has to go through some early stages. First clean and degrease with a solution of soap and water and then are pickled with a solution of caustic soda. To mitigate the effect of etching agents, aluminum is neutralized in a solution of nitric acid.

The next step will move to the decisive phase electrolysis. The aluminum is immersed in a solution of sulfuric acid (15-20%) to which is applied a direct current of between 13 to 17 volts, an intensity of 1-1.5 amps per square decimeter. This current causes the release of oxygen going in an even layer in the profile, the thickness (microns) depend on the time of application of the current.

By increasing the thickness, the oxide layer becomes porous, which is why he was later applied one last process, called "sealed " to remove this porosity. Basically latter treatment involves immersing the aluminum in very hot water.

The anodizing process causes the resulting color or tone is directly integrated into the aluminum, so the strength of the tone or color will be greater than with any other treatment .


The anodized aluminum inferred a distinctly metallic colors, being the color of the aluminum itself after the process aspect. Anodizing gives added protection to color.

This variety of aluminum is the most resistant to corrosion, abrasion and suffering less wear compared to external agents and the meteorology. No dirty easily and cleaned with relative ease.

The anodized color chart is not as extensive as the RAL lacquer. Are the standard anodized silver, stainless steel, bronze, gold, black and burgundy. As we can find special anodized blue, green, titanium, etc. All these shades can be found in matte or gloss.