The Five Process Of Anodizing Aluminum

by Reece

Ddprototype is a leading company. The company works with a wide range of clients in various industries. Other than CNC machining services, Ddprototyping also offers rapid prototyping and anodizing aluminum services. The company offers varying types of each of the services mentioned above. In this post, we focus on anodizing aluminum services.

The process of anodizing aluminum

The process is not as complicated as you may think. Below is a break down of each step and how it is done;

Step 1: Cleaning

The first step of the process is the cleaning of the aluminum parts. The process can not be completed successfully without this step. Therefore, the parts must be cleaned and rinsed. This can be done with water.

Step 2: soaking in electrolytic solutions

In the next step, aluminum parts are placed into a bath containing an electrolytic solution. The solution can either contain sulfuric or chromic acid. The role of using these chemicals is to provide an electrically conductive coating made up of both positive and negative ions.

Step 3: The electrochemical reaction

Here, a positive electric charge is sent through the metal parts. At the same time, a negative electric charge is applied to the plates through the electrolyte. The electric current triggers the attraction of the negatively charged plates to the positive ions as the negative ions are attracted to the aluminum surface simultaneously. Note that the aluminum part is used as the positive anode. This is arguably the most important part of the process as it plays a significant role in achieving the primary objective.

Step 4: Formation of the barrier layer

The positive ions formed in the reaction need to find a way to escape. Therefore, pores open up on the aluminum surface. As the pores dig deep into the part’s surface, a reaction is triggered between the aluminum surface and the negatively charges ions. This results in the formation of a barrier layer known as aluminum oxide. This is the objective of the entire process.

Continued application of electric current causes the moderately weak and volatile areas of the pores to infiltrate even deeper into the substrate. When this happens, a series of column-like hollow structures are formed. The longer the application of electric current, the deeper these columns penetrate the substrate.

Step 5: Rinsing

When the process is complete, you can rinse the part in water. Doing this helps to seal the surface, leaving you with a hard, natural coating of aluminum oxide. According to the Mohs scale of hardness, aluminum oxide is rated at 9 out of 10. This makes it one of the hardest metals in existence. It also allows the part to withstand chemical attracts and scratches. It also enhances its aesthetic appeal.


Note that the process may differ from one company to the next. It may also vary from one type of anodizing aluminum to the other. However, regardless of the company and the type of process, the objective and how it is achieved in basically the same.

You may also like

Leave a Comment