Che cos'è l'anodizzazione del titanio: Una guida definitiva

Titanium anodizing is also a commonly approached method that alters the properties of titanium, which helps create a layer of protection against corrosion.

This article below discusses what is titanium anodizing, its process, pros and cons, and much more. You can go through it to learn more about titanium anodizing.

What is Titanium Anodizing?

Titanium anodizing refers to a process in which an oxide layer is formed over the surface of titanium components. This process is carried out through an electrolytic process, which changes the chemical, mechanical, and even aesthetic properties of titanium.

Anodizing enhances wear and corrosion resistance and slows down the process of corrosion for many titanium components. It even helps to make titanium more absorbent for coloring so that its aesthetic finish can be enhanced.

How Titanium Anodizing Works

Titanium anodizing works by building a layer of oxide on the component with the help of an electrochemical process. An oxide film is created to enhance the surface's durability and functionality.

Steps for the Titanium Anodizing Process

The steps involved in the anodizing process of titanium have the following steps:

Cleaning the Surface

Il titanium workpiece is first cleaned, and for this, it is immersed in an alkaline bath. It helps to remove all types of grease, dirt, or debris. It is a very crucial stage, as any contaminants on the surface may lead to problems with the anodizing process.

Setting Up the Anodizing Equipment

The cleaned titanium component is then set up in the anodizing equipment. The component is connected to the power supply at its positive terminal and acts as an anode.

Process of Electrolysis

The anode is dipped in an electrolytic bath, which is either phosphoric or sulfuric acid. This solution allows for the flow of current and helps carry out anodization.

Control of Temperature, Current, and Voltage

The layer of oxide created on the titanium surface is dependent on the current, temperature, and voltage prevalent during the process. When the voltage is high, the layers are thicker and have different colors. However, it needs very careful regulation to achieve the required outcome.

Post Treatment

Once the process of anodization is completed, the titanium component is rinsed properly to remove any electrolytes. Sometimes, a sealing step is also done in which the anodized component is immersed in boiling water, which closes its pores.

Pros and Cons of Titanium Anodizing

The pros and cons of titanium anodizing are as follows:

Pro

• It reduces the friction on titanium components and adds hardness, which helps reduce galling risk areas where the surface is abraded.
• It enhances the corrosion resistance.
• The surfaces become biocompatible and do not contain any contamination.
• The process is low-cost and durable.
• It offers a wide color spectrum followed by excellent cosmetic quality.

Contro

• It is very challenging to achieve precise color control and maintain it because the process is completely electronic.
• The electrochemical baths used for the process of titanium anodizing are toxic and harmful, and therefore health concerns are a problem.
• When the layer of anodizing is damaged, the time taken for repair is long and requires sufficient oxygen for oxidation purposes.
• By anodizing titanium, the chance of corrosion is not completely eliminated. Some exposures like methanol do lead to stress corrosion in titanium alloys.

Types of Titanium Anodizing

There are different types of anodizing, which are the following:

Type 1: Type 1 titanium anodizing builds a semi-conducting oxide layer, which proves to be useful for extrusion process and thermal control.

Type 2: Type 2 titanium anodizing creates a wear-resistant and thick layer of coating.

Type 3: Type 3 titanium anodizing adds a touch of different colors to titanium, ranging from gold to green.

Type 4: It adds a self-lubricating layer on the titanium surface, which helps in reducing friction.

Natural Oxidation: Titanium naturally also forms a layer of oxide over it, which is thin and protective and grows over a period of time.

What Are the Available Colors for Anodized Titanium?

The colors available for the anodized titanium are the following:

• Cyan
• Green
• Magenta
• Bronzo
• Yellow
• Blue

The color of the anodized titanium component is based on the thickness of the layer created. Hence, a wide range of colors is possible based on how thick the oxidized layer is.

Materials Needed to Anodize Titanium

The process of titanium anodizing requires some important materials, and these are as follows:

Electrolyte: The electrolyte solution consists of a mild sulfuric acid or sodium tetraborate solution.

Plastic Tank: This allows the component to be immersed. It can be lined using aluminum foil and filled with electrolytic solution.

DC Power Supply: A DC power supply that can supply a voltage of 0 to 30 volts to lead the anodizing process.

Wires: The wires will be used for connecting the aluminum foil to the power supply and the titanium component to the power supply as well.

Applications Of Titanium Anodizing

The anodized titanium is widely used in different industries, and some of these are discussed below:

Industria aerospaziale

Anodized titanium components offer lightweight and corrosion resistance. It is, therefore, suitable for fasteners, hydraulic systems, and aircraft housings. These components can withstand harsh conditions and enhance lifespan.

Industria medica

Il industria medica also uses anodized titanium as it offers excellent biocompatibilità. These components are suitable for use as implants and surgical instruments that need to work well with bodily fluids. These components can also be sterilized without corroding.

Industria automobilistica

In the automobile sector, anodized titanium offers a high strength-to-weight ratio; hence, it is suitable for components like connecting rods.

It offers a strength that is commendable and it is also lightweight. Various components like mufflers are also corrosion-resistant and also can work with high heat.

Beni di consumo

Consumer goods like frames, glasses, watches, and sports goods are also manufactured with anodized titanium. It ensures the aesthetic appeal of the goods and protects them from environmental factors, making them resistant to wear and tear.

Conclusione

Anodized titanium is used in various applications and offers excellent properties.

If you are looking forward to getting titanium components anodized for your applications, you can get in touch with DEK. We have an experienced team with advanced equipment that allows us to offer excellent anodizing on titanium components.

Titanium Anodizing FAQs

What are the key differences between type 2 and type 3 titanium anodizing?

Type 2 anodizing of titanium uses sulfuric acid, which helps in dying in every color. Type 3 anodizing is carried out with a hard coat, which creates a highly abrasion-resistant coating.

Does anodized titanium fade?

No, anodized titanium doesn't fade easily.

How long does anodizing on titanium last?

Anodizing on titanium lasts throughout if it is not scratched.

Why does anodized titanium change color?

Anodizing creates an oxide layer on the titanium component, which is then filled with a pigment to create the required color.

Does heat remove anodizing?

Heat doesn't remove anodizing, but when subjected to a very high temperature, the anodized titanium may end up discoloring.