Anodizing is a technique for expanding the natural oxide layer of metals, specifically aluminum.  Anodizing can relate to both a specific aluminum alloy and a process. The process is called anodizing because the part to be treated forms the anode electrode of an electrolytic cell. It increases resistance to corrosion and wear, and provides better adhesion for paint primers and glues than bare metal does.

Anodizing is also a method for changing the surface chemistry of metals and other substances. This action of anodizing protects against corrosion, enhances aesthetic qualities, resists scratching, and as far as durable surface finishes, this is it. Anodizing can be used on many materials, however, for the purpose of this article, we will narrow the topic down to aluminum.

About Anodizing Aluminum

How Is It Done?

When prepping aluminum for anodizing, the product is rinsed and cleaned and placed in an electrolytic solution such as sulfuric acid. Out of this comes a positive electric charge which is applied to the aluminum. Meanwhile, the negative charge is applied to plates suspended in the electrolyte.

What Is A Barrier Layer In Anodizing?

The previous chemical reaction causes pores to form on the surface of the aluminum as extra positive ions escape. These pores begin to erode down into the substrate. A barrier layer forms when the aluminum at the surface combines with the negatively charged ions, creating aluminum oxide. 

What Is Hard Anodizing?

Also known as Type III, this offers greater corrosion protection in extreme environments or with moving mechanical parts. This requires more time and money but allows for a superior result.

How Color Is Added to Anodizing

Typically, aluminum is seen in its colored state. When all the processes prior to this are done correctly, stable pores create color. The pores are empty and absorb the color when poured in and permanently sealed off. The color is so durable, as it runs deep, so as to not allow any scratching off of the coloring.

For additional information regarding anodizing aluminum, contact the professionals at Decorative Electro Coatings.


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