A Brief Explaintion About Anodized Aluminum

Aluminum anodizing is one of the most durable post-treatment processes. This process improves the shape and function of CNC machine parts. Die-casted aluminum parts encourage the connection between the glue and primer. Anodized aluminum is one of the trendiest materials in commercial and industrial products. Here is more imminent into the pros of anodized aluminum in CNC machining.

But one thing that comes to mind is what anodized aluminum is? In a nutshell, we can say that anodizing is a method used to expand the oxide coating on the aluminum surface. But, that is not enough; you can’t easily understand this topic without details.

What is anodizing?

Anodizing is generally known as an electrochemical process. We clean the surface to anodize aluminum components for CNC machining and die-casting. This process converts the surface into a durable, decorative finish. Moreover, in corrosion-resistant, and anodic oxide finish. Aluminum is a material that is ideally suited. The other non-ferrous metals that are titanium and magnesium. They are also suitable for the anodizing process. Anodic oxide structure comes from the aluminum substrate. And it consists entirely of aluminum oxide. Moreover, aluminum has the power to produce its own corrosion-resistant coating.

We do not apply the aluminum oxide to the surface like plating or paint. Instead, it integrates fully with the essential aluminum substrate. And also make it difficult to chip or peel. It has a highly-controlled, absorbent structure. That permits secondary processes such as sealing and coloring. We dip the aluminum into an acid electrolyte bath to complete the anodizing process.

Subsequently, there is also a need to pass an electric current through the medium. A cathode is mounted within the tank of anodizing. The aluminum works as an anode to release the oxygen ions from the electrolyte. The purpose of this is to merge it with the aluminum atoms at the component’s surface.

CNC Machining and anodizing:

CNC machined aluminum parts that have undergone the anodizing process are trendy. These are famous in the electronics and aerospace industries. They offer outstanding strength durability and are also attractive. Also, Anodizing makes it easier to include color on CNC machined aluminum components.

The main types of anodizing:

There are generally main four types of anodized aluminum;

1. Chromic acid anodizing (CAA):

The chromic acid anodizing process has a skinny coat, unlike other types of anodizing. It is gray and absorbs fewer colors when tinted. That’s why people don’t usually use it for decorative finishes. Normally tinted black as protective and a non-reflective caring coating.

2. Boric-sulfuric acid anodizing (BSAA):

We call BSAA an alternative to chromic acid anodizes. It is true that the BSAA shows positivity towards the environment. Moreover also towards the worker safety and good health. Paint bond is equal to or better than chromic acid.

Moreover, the method is more energy-efficient than chrome-based methods. Therefore, we see its use in precision machinings such as aerospace technology and vehicles.

3. Sulfuric acid anodizing:

This is the most normal process of anodized aluminum. This process is use as the best option. And appropriates for applications where we need friction and hardness resistance.

Yet, the probable presence of corrosive acid residue is objectionable in areas where parts are under considerable pressure. The parts of an aircraft are the best example of this.

4. Hard Anodizing:

The Hardcoat anodizing is significantly denser and thicker than sulfuric anodizing. Hardcoat anodizing is suitable for aluminum components. That needs safety from extreme wear, corrosion, and abrasion. It is also excellent for better electrical insulation. Moreover, also ideal for salvaging damaged or miss-machined parts.

Color options available for anodized aluminum:

The porous nature of aluminum oxide permits it to absorb dyes well. And later sealing helps to avoid color loss in service. Here are some of the best-anodized aluminum colors that are in use;

  • Black
  • Red
  • Blue
  • Green
  • Urban Grey
  • Coyote Brown
  • Gold

Anodized aluminum color chart:

Aluminum service providers offer you a complete aluminum anodized color chart. But, in common, you will search for a complete collection of anodized colors. Major airplane manufacturing companies use best-anodized aluminum colors. The three main types of coloring are as under;

  • Electrolytic coloring: The concluding outcome is resistant and suitable for the weather
  • Anodic coloring: The concluding outcome is an oxide coating that is harder and more resistant to scratch
  • Combined coloring: With this type of method, an extensive range of colors that we can achieve 

Available thicknesses and uses:

The component will be more or less resistant, depending upon the anodizing layer. As for its use, it is notable according to the width of the oxide coating, as follows;

  • Classes 5 – 10: for indoor use only, 5 – 9 micron and 10 – 14 micron
  • Class 15: for outdoor use only, 15 – 19 microns
  • Class 20: for use in marine and industrial conditions, 20 – 24 microns
  • Class 25: for use in marine and industrial conditions, 25 – 29 microns

We can find the following anodized aluminum products in the construction department;

  • Consumer electronics and technology
  • Household appliances
  • Sporting equipment
  • Electrical engines

The behavior of the different types of aluminum for anodizing:

Aluminum has other classes in sequence according to its hardness and alloy. Remember that the bigger the series, the more complex the material. In the following table, the behavior of the aluminum type according to its sequel is available in detail;

Alloy RefBehavior DescriptionDecorative MattDecorative GlowProtection
1050Aluminum Pure 99,5 %BadBadVery Good
1085Aluminum Pure 99,0 %GoodVery GoodVery Good
1090Aluminum Pure – BicapaBadVery GoodVery Good
1200Aluminum Pure 99,0 %GoodGoodVery Good
2011Aluminum – CopperBadBadGood
2014Aluminum – CopperBadBadRegular
2017Aluminum – CopperRegularRegularRegular
2024Aluminum – CopperBadBadRegular
3003Aluminum – ManganeseRegularRegularVery Good
3004Aluminum – ManganeseRegularRegularVery Good
5005Aluminum – MagnesiumVery GoodGoodVery Good
5019Aluminum – MagnesiumBadBadVery Good
5052Aluminum – MagnesiumGoodGoodVery Good
5083Aluminum – MagnesiumRegularRegularVery Good
5086Aluminum – MagnesiumRegularRegularVery Good
5154Aluminum – MagnesiumGoodGoodVery Good
5251Aluminum – MagnesiumGoodGoodVery Good
5754Aluminum – MagnesiumGoodGoodVery Good
5784Aluminum – MagnesiumVery GoodGoodVery Good
6005Aluminum – Magnesium – SiliconGoodGoodVery Good
6026Aluminum – Magnesium – SiliconGoodGoodGood
6060Aluminum – Magnesium – SiliconVery GoodVery GoodVery Good
6061Aluminum – Magnesium – SiliconRegularRegularVery Good
6063Aluminum – Magnesium – SiliconVery GoodVery GoodVery Good
6082Aluminum – Magnesium – SiliconRegularRegularVery Good
6101Aluminum – Magnesium – SiliconRegularRegularVery Good
6401Aluminum – Magnesium – SiliconGoodVery GoodVery Good
6463Aluminum – Magnesium – SiliconGoodVery GoodVery Good
7020Aluminum – ZincRegularRegularGood
7075Aluminum – ZincRegularRegularGood
7022Aluminum – ZincBadBadGood

The anodizing process of aluminum is very common. And is famous in the construction industry, aerospace, and vehicle manufacturing industries. And I am sure that the table as mentioned above will be helpful for everyone.

Significant benefits of anodized aluminum:

Following are the significant benefits of anodized aluminum;

1. Corrosion Resistance:

We can define corrosion resistance as the ability of a material to resist corrosion damage caused by oxidation. Moreover, also caused by other chemical reactions. Anodized aluminum is extra resistant to rust than standard aluminum. Of course, Anodized and standard are both best rust-resistant. But when we compare, the anodized aluminum wins the battle.

The difference is because of the thickness of the coating. The large multinational industries and manufacturing companies are aware of its benefits. And we cannot use this significant element.

2. Dyeing:

We can dye anodized aluminum in various colors to make aluminum products more attractive. We do not stain the standard aluminum products. And the original chrome color of standard aluminum remains active. But anodized aluminum looks very attractive because of its colors. Aluminum has to go through many processes to provide it with different colors.

3. Lubrication:

No doubt, the critical benefit of anodized aluminum is that it is rust-resistant. Moreover, anodized aluminum also has more lubrication quality than standard aluminum. That is why large manufacturing companies give preference to anodized aluminum parts.

4. Increased adhesion:

In the end, anodized aluminum offers superior adhesion for primers and adhesives. The reason for better adhesion is due to the oxide surface of anodized aluminum.

Standard aluminum does not have deeper pores. But anodized aluminum has deeper pores, and that makes it better. In this era, all well-reputed manufacturing and designing industries do not ingore its benefits.

Final words:

After reading this post, I am hopeful that you now have every detail about anodized aluminum. First, I explained the definition of anodizing straightforwardly. Afterward, the main types of anodizing are presented for better understanding purposes.

The classes described in detail are chromic acid anodizing (CAA), Boric-sulfuric acid anodizing (BSAA). Moreover, sulfuric acid anodizing, and hard anodizing are further classes. I also explained the detail about colors available in anodized aluminum.

In the second part, an explanation mentioned uses and thickness of anodized aluminum. You are now also able to understand the behavior of aluminum about different alloys. At the last advantages of anodized aluminum explained in a precise way. I need your feedback via valuable comments.

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