Etch aluminum

The etching of aluminum is used in various fields with different objectives. How the process of aluminum etching works and what should be considered, we have summarized the following for you.

Fundamentals of aluminum

Aluminum is a versatile light metal. After oxygen and silicon, it is the third most common element, but was discovered only in the 19th century. Today, light metal with its extremely high thermal and electrical conductivity is becoming increasingly important. Aluminum is an extraordinarily reactive metal.

The oxidation of aluminum

Therefore, upon contact with oxygen, an oxide layer forms on the light metal within a few minutes. But water and oxygen together lead to oxidation, in which case a multilayer oxide layer is formed. In many cases, the oxidation layer is the reason for the use of aluminum, but this layer protects the aluminum from further reactions. Depending on how the aluminum is to be treated further, this oxide layer may also have to be removed.

Ways to remove the oxide layer

This oxide layer can be removed chemically or mechanically. The latter by simply grinding the aluminum. During etching, this process is carried out chemically, taking advantage of the reactivity of the light metal. There are numerous applications where it is essential to remove this oxide layer:

  • welding aluminum
  • when brazing aluminum (soft and brazing)
  • before painting aluminum
  • before controlled oxidation of aluminum, anodizing
  • chromium plating, coppering, nickel plating, brass cutting etc. in front of the aluminum

Etch aluminum

The easiest way to etch aluminum is with sodium and oxygen (NaOH etching). The reactive properties of aluminum are used. Because of the natural oxidation, only a passivation of the oxidation takes place, which ultimately also constitutes an etching. So first the oxide layer on the aluminum has to be removed to be able to etch the aluminum itself.

The use of a sodium hydroxide (NaOH) for aluminum etching

Therefore, sodium and water are mixed into a lye. The sodium now etches away the oxide layer, while the aluminum can now react directly on the water. At the same time, sodium prevents the immediate formation of a new oxide layer. In this process, the reaction of the aluminum workpiece is relatively violent.

When etching aluminum, take adequate safety measures

Therefore, it is important to wear appropriate protective clothing when etching aluminum. In addition, harmful vapors may form during etching. Good ventilation and respiratory protection are therefore mandatory. Under no circumstances should you handle aluminum with other chemicals as aluminum is really highly reactive. Even when aluminum is melted, hydrogen is released, which can lead to violent reactions.

Tips & Tricks

In the house journal you will find guides and instructions for all conceivable processing methods of aluminum. This includes the high-gloss polishing of aluminum.

Video Board: How To Etch Aluminium