Passivation of Aluminum- Passivating Surface Finishing - Sunrise Metal


Passivation is the process of depositing a layer of oxide on the surface of the metal. In the context of corrosion, the passivation forms a non-reactive layer that protects against further corrosion attacks.

Further, due to air, a film layer forms on aluminum alloy die castings. After this, the surface state of aluminum alloy die castings becomes a passive state of corrosion resistance.

If you want to protect your aluminum alloy items, then the passivation of aluminum die casting is the cost-effective way. It is about a nanometer thick and causes no change to your metal alloy, be it aluminum or zinc.

Here are some benefits of our passivation for aluminum alloy die casting.

Preventing corrosion with ultra-thin layers of aluminum oxide

  • High-quality surface finish: After the passivation, the thickness of parts will not increase, and there will be no change in color.

Therefore, it adds value to aluminum products while making the operation more convenient.

  • Makes metal economical: The passivation process takes place in a non-reactive state. And, the continuous addition of a passivation agent during the process makes the metal more economical.
  • Self-healing from scratches: With the passivation, the oxygen molecular structure of film gets improved on the surface of aluminum alloy die castings.

This makes the film layer dense and offers a self-healing effect as well. It means the aluminum alloy gets hailed from scratch itself.

  • Offer stability: As compared to traditional anti-corrosion methods, passivation is a more stable and corrosion-resistant way to protect aluminum items.

Our High-Quality the Passivation Process

When aluminum is pure, it already undergoes a natural process of oxidation. During which a layer of aluminum oxide forms on its surface when it comes into contact with oxygen.

Unfortunately, not every aluminum alloy has the ability to form an oxide layer, which makes them more vulnerable to corrosion and other harm.

This is why Sunrise Metal prefers the passivation for aluminum alloy die castings. We are specializing in the passivation for aluminum alloy die castings.

Our skilled and experienced professionals ensure high-quality passivation for all your aluminum alloy finishing needs.

Sunrise Metal is in aluminum die casting manufacturing for over ten years.

Here is the process that Sunrise Metal follows for the passivation of aluminum alloy die castings:


Step 1: Clean the surface of aluminum alloy die casting

  • We clean the surface and do it with pre-degreasing on the surface, which will be followed by the main degreasing
  • Now, we do water rinsing of the metal part and dry it.

Step 2: Place the metal part in an acidic passivating bath

  • After cleaning the metal surface, we will submerge it into an acidic bath for about 20 to 30 minutes.
  • Next, we will neutralize the through a bath in aqueous sodium hydroxide.

Step 3: Rinse the metal piece with water

Passivation Production Line-Sunrise Metal

  • In the end, we will rinse the metal part with water

It is a complete process that is suitable for different aluminum alloy products and passivation environments.

Finally, with an advanced measurement lab, our professionals do a detailed inspection of aluminum parts after the completion of the passivation process.

It helps match the client’s high requirements and international standards.

What is the Difference Between Pickling and Passivation?

Pickling and passivation are two different terms. They basically are forms of chemical metal finishing that offer protective nature to metal, especially against corrosion.

In other terms, pickling and passivation are the processes where the metal or aluminum is submerged in a bathing liquid. It helps remove imperfections from the surface of the metal.

Let’s understand the difference between the two in detail.

●      Pickling uses acids to treat impurities or to remove imperfections from the surface of the metal. You will see a big change to the metal after pickling finishing.

●      The passivation applies either nitric acid or citric acid to remove imperfections from the metal surface. These two acids are less aggressive as compared to the acids used in pickling. And it does not change the properties of the metal and is the best use for aluminum alloy die castings. The oxide layer formed by the passivation is not so thick.

Is Passivation Necessary for Aluminum Casting Parts?

There are some imperfections and greasy things on aluminum casting parts. The surface of the components also has a naturally-occurring oxide film due to oxygen exposure.

Then when it is in operation, it is subject to abrasion and corrosion and can be weakened or damaged. To remove all and to give a new finish to the parts, passivation is necessary.

How Long Does the Passivation of Aluminum Last?

Passivation is a cost-effective and safe metal finishing process that prevents aluminum alloy die castings from damage and corrosion.

It can last up to many years and is best for all aluminum alloy items, including handles, machine parts, etc.

In addition to aluminum, a passivation is a great option for other metals, including steel, zinc, copper, and more.

Is the Passivation of Aluminum a Cleaning Process?

Yes, the passivation is a cleaning process, but in addition to this, it also protects the metal surface from corrosion. It forms a protective layer on the metal surface, which is very thin and not noticeable as well.

Further, it minimizes surface oxidation and offers some resistance to a light chemical attack on aluminum alloys.

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