Natural and artificial color of aluminum

The color of aluminum depends on the complementary metals also present in the alloy and on the degree of oxidation. Depending on where it is found and its purity, aluminum, as raw material, moves between light gray and dull silver. The starting color is also influenced by the oxygen supply and the age.

Artificial dyeing method

The central process that leads to the coloring of aluminum is the natural oxidation. When mining and extracting aluminum, in many cases the first oxygen contact of the metal occurs. In the first few days, the resulting oxidation without artificial action leads to a change in the natural color.

In order to change or influence the original color, four technical methods are possible:

1. Anodizing

The most common dyeing process is the controlled oxidation of aluminum, in which different dyes are integrated into the resulting oxidation layer. Depending on the process and alloying partners, the color layer may undergo a stronger and deeper or a very superficial molecular bond.

2. Painting

When aluminum sheet is painted, it resembles a superficial painting of aluminum. The color corresponds to external sealing and only holds on non-contaminated surfaces.

3. Darken chemically

When aluminum surfaces are to be darkened or even completely blackened, the chemical method of burnishing is usually used. The aluminum is placed in a heated dipping solution and the chemical reaction causes the color change. In this method, the type of alloy exerts great influence on the color.

4. Glue

A simple and simple way is to foil the aluminum. It is important to have special foil and the hermetic air seal of the aluminum to prevent further oxidation under the foil.

Tips & Tricks

If you encounter painted, painted or foiled aluminum and then paint it off or remove it from the film, natural oxidation sets in. The color developed after the work-up also changes without technical intervention and changes over time slower, but constantly.

Video Board: Artificial coloring is Killing American Red #40, Yellow #5 and# 6, Blue#1, Green#1