Tips For Anodization And How The Process Works

by Angel Waldrop

Aluminum is one of the most popularly used manufacturing metals in various industries. Its popularity can be attributed to its superior qualities. While the metal is incredible in many ways, its main downside is that it is prone to corrosion. Most users employ the anodization process to help with this. In this post, we discuss tips for anodization and how the process works.

The anodization process

The anodization aluminum process takes the following steps;

  • Pre-cleaning– this is where the aluminum is cleaned. The cleaning is usually done using an alkaline detergent. The detergent works by removing all foreign contaminants on the metal. It also removes oil on the surface, leaving it clean and smooth. It also leaves the coat even and ready for anodization.
  • Removal of top layer– after cleaning, the top layer of the metal is removed using the chemical etching technique. Here, the native oxide film on the aluminum metal is eliminated using acid. The role of this step is to ensure that the process of anodizing is perfect. Some people go the extra mile of dipping the etched aluminum inside nitric acid to remove any residue left behind after the cleaning and etching.
  • Anodizing– the next step is creating the protective oxide layer. Here, the aluminum is submerged inside an electrolytic cell. Direct current is also passed through the metal. The aluminum becomes the positive terminal of the cell, initializing an electrochemical reaction. The reaction occurs on the surface of the metal. Aluminum atoms are extracted from the bare metal, creating a porous structure. As the reaction continues, oxygen reacts with the free atoms forming an aluminum oxide layer.

Tips for anodizing aluminum

The tips below should come in handy when anodizing aluminum;

1. Consider elements that influence the thickness of the barrier layer

The applied voltage usually determines the barrier layer (oxide layer) thickness and the solution used. The type of solution applied in the electrolytic cell plays a significant role in the thickness and other oxide layer qualities, like elasticity, flexibility, and resistance to wear and corrosion.

2. Look into various methods of anodizing aluminum

There are three main methods of anodizing aluminum and they are categorized depending on the solution used. Sulphuric acid is the most commonly applied solution. It is used in two of the three methods. The method of anodizing aluminum determines the qualities or characteristics of the resulting oxide layer. For instance, the Type I anodizing method results in a thin, ductile, slight wear and corrosion-resistant oxide layer.

On the other hand, the Type III anodizing method, also known as hard, results in the thickest oxide layer. The ease of coloring or dying the metal after anodizing is also influenced by the method. Therefore, it would help if you considered the basics of each method before selecting one.

3. Consider the applications of the anodized metal

However you wish to apply the anodized metal will impact the voltage you apply, temperature, and the method of anodizing you select.


Anodizing metals like aluminum are highly beneficial. It results in wear, rust, and corrosion-resistant material. It also helps improve the metal’s aesthetic appeal, allowing you to apply it in various industries.

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