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What is Anodized Aluminum? A Complete Guide to the Process and its Advantages

What is Anodized Aluminum? A Complete Guide to the Process and its Advantages
Before we talk about what is anodizing aluminum, we have to understand the term anodizing. If explained in simple words, anodizing is an electrochemical process in which an oxide film forms on the metal surface. The process changes the surface chemistry of metals, rendering them durable, decorative, and corrosion-resistant. Anodized metal has improved aesthetic quality, a durable surface finish, and protection against corrosion. Anodized metal has improved aesthetic quality, a durable surface finish, and protection against corrosion.

Magnesium and titanium are nonferrous materials that can be anodized. However, aluminum is the most suitable metal. It is immersed in a number of tanks and when a chemical reaction takes place, an anodic layer is formed at the surface that is produced by the metal itself.

The layer has durability because it hasn’t been applied or painted but takes a form from aluminum. Anodized aluminum is three times harder than the raw material, giving long-lasting strength and aesthetic appeal to the metal.

All You Need to Know About Anodized Aluminum

Process of Anodizing Aluminum

Before aluminum is anodized, its surface is thoroughly cleaned and rinsed. Then, it is placed in the electrolytic solution of sulfuric acid, and an electric current is flown through it. Sulfuric acid is an electrically conductive solution, with many positive and negative ions that are used for swapping.

When an electric charge is applied, a chemical reaction takes place that thickens the oxide layer on the surface of the aluminum. Not only does this increase the durability of the metal but also provides a clear finishing. In some cases, anodizing can introduce a different color to the metal.

The first sulfuric acid anodizing process was patented by Gower and O'Brien in 1927. The chemical process has remained pretty much the same since this time and sulfuric acid remains the most common anodizing electrolyte. In aluminum anodizing, plenty of protective layers are added to the material. A cover is formed when positive ions are removed from the surface layer, giving the metal sheet a perfect finish and prevents wear and scratches.

Currently, there are four variations of the aluminum anodizing process:
  • Type I – Also known as the most basic type, chromic acid is used as an electrolyte to produce a thin anodized layer on the aluminum part.
  • Type II – In this type, sulfuric acid is used to produce a thicker anodized layer.
  • Type III –  Similar to type II because it uses sulfuric acid but produces a thicker layer because electric current is passed until the depth of the pores exceeds 10 microns. Also called ‘Hard Anodizing’, this process is expensive but produces better results.
  • Chemical Film/Alodine – Alodine is used for chemical baths to produce results that are comparable to anodizing.

Need for Corrosion Protection

While aluminum doesn’t rust, it can oxidize when oxygen is present. Oxidization means reacting with oxygen, which is a very reactive element. Oxygen is capable of readily forming compounds with other elements. When it reacts with aluminum, an additional layer of aluminum oxide is formed, which is further corrosion resistance.

Being exposed to more than just water and air, aluminum must withstand being affected by the environment. Owing to global warming and changes in the climate, there are factors like acid rain and saltwater that can exploit the weaknesses on the surface. Such exposure may lead to many problems ranging from mere surface discoloration to serious mechanical failures.

Color of Anodized Aluminum

In its natural state, anodized aluminum is bright silver in color and may have a matte or a bright finish. We think of colored anodic films when we picture anodized aluminum in our minds. The pores found on the surface facilitate the introduction of pigments or tints, allowing you to give the color of your choice to the metal.

The material has such versatility that it can be made to look like other metals like copper, bronze, stainless steel, gold, and brass. The nature of the anodized aluminum allows the product to stay true to its color for a lifetime. No matter what color you choose, it will never chip or peel.

Advantages of Anodized Aluminum

Aesthetic Appeal

When aluminum is anodized, it provides beauty to any item. Usually, people find a metallic look of the surface that is caused by uniform electrochemical etching and reflection of light. The deeper the pores are, the rougher will be the surface but that will also increase the durability of the color and cause abrasion resistance. 

When lighting hits the surface, it interacts with the color and the surface, bouncing back at different wavelengths. That is why when it reaches your eye, you can see the distinctive shine on the surface. However, you can look for various texture options like brushed, pebble, stone, or stucco. This helps in giving your product a unique look.

Light in Weight

One of the main reasons that anodized aluminum is suitable for product manufacturing is its lightweight. As compared to metals like brass, copper, or stainless steel, it is 60% lighter in weight. Not only does this reduce the shipping cost but also resolves plenty of design issues.

Whether we are talking about consumer goods or architecture designs, anodized aluminum presents plenty of options being a durable, light-weight, and attractive material. In addition to this, anodizing is done under strict conditions and following best practices. Thus, its production conforms to all safety and environmental policies.

Maintenance Ease

There is no denying the durability of anodized aluminum parts that provide them with a long lifespan and bring economic gains with it. Because of all the durability traits, minimum effort is required for the maintenance of anodized alloys.

They can easily be used in strained conditions and do not have to be replaced often. To restore the metal to its original anodized profile, all one needs to do is wash and rinse with mild soap and water. For challenging deposits, mild abrasive cleaners can be used.

Minimum Cost

The other benefits attributed to anodized aluminum also help in reducing overall costs. Because of low maintenance, one doesn’t need to spend a lot of money on keeping the product in its best shape. 

The minimum weight of anodized aluminum also makes it easier to ship to the manufacturing facility or job site. Its high strength-to-weight ratio makes it an ideal choice over other metals while providing the same visual effect. As it is the only metal that is 100% recyclable, its renewability also makes it cheap and environment-friendly.

Get Anodized Aluminum Profiles from BK-ALPROF

BK-ALPROF was founded in 1999 and since then, it has become a world-class aluminum extrusion company. It is an experienced Russian aluminum profile manufacturer which supplies profiles of all shapes and sizes — glazing systems, aluminum beams, extruded aluminum tubes of any shape and size, aluminum angles, etc. Our raw materials comply with the quality certificates and international standards.

Specializing in anodic coating and anodizing aluminum shapes, BK-ALPROF offers attractive aluminum finishing techniques. We also deal in the casting of solid extrusion billets and the production of translucent structures. All the extrusions are made from alloys 6060 and 6063. Custom packaging solutions are available for all extruded aluminum shapes.

Equipped with modern and technologically advanced machinery, our company provides fast manufacturing of machinery starting from 7 business days. To top it all, we offer affordable prices and convenient delivery terms. All you need to do is assess your needs and get in touch with the custom design service.