Passivation

Metal surface passivation treatment is a common method of metal surface treatment, which aims to change the chemical properties of the metal surface to form a protective layer with good corrosion resistance and wear resistance, thereby improving the corrosion resistance and service life of metal materials. This article will introduce the principles, common methods, and application fields of passivation treatment.

1. The principle of passivation treatment

Metal materials are prone to oxidation reactions in the atmosphere, producing metal oxides, which can lead to metal corrosion. And passivation treatment forms a dense oxide film on the metal surface, blocking the contact between the metal and the external medium, thereby playing a protective role for the metal. This type of oxide film can reduce the activity of the metal surface, making it less prone to oxidation reactions under certain conditions, thereby improving the corrosion resistance of the metal.

2. Common passivation treatment methods

1) Acid pickling passivation: This is one of the most common passivation treatment methods. By immersing metal materials in a dilute acid solution, the metal surface reacts with acid to form a dense oxide film. Common acids include nitric acid, phosphoric acid, and sulfuric acid. The acid pickling and passivation method is suitable for surface treatment of metal materials such as iron, copper, and aluminum.

2) Electrochemical passivation: This method utilizes the principle of electrochemistry to apply an external current to the metal surface, causing an oxidation-reduction reaction to occur on the metal surface, generating a dense oxide film. This method has the advantages of good passivation effect and simple operation, and is suitable for different types of metal materials.

3) Chemical deposition passivation: This method involves depositing a layer of metal compound on the metal surface to form a protective thin film. Common chemical deposition passivation methods include galvanizing, chromium plating, and nickel plating.

3. The application areas of passivation treatment

Passivation is widely used in various fields, especially in the manufacturing industry, playing an important role. The following are several common application areas:

1) Automotive manufacturing industry: For the manufacturing of automotive components, passivation treatment can improve their corrosion resistance and extend their service life. For example, metal components such as the chassis and body of a car often undergo passivation treatment to enhance their corrosion resistance.

2) Electronic and electrical industry: In the manufacturing process of electronic and electrical appliances, metal components often require passivation treatment to improve their corrosion resistance and conductivity. For example, metal contacts and circuit boards in electronic products can be passivated to increase their stability and reliability.

3) Construction industry: In the manufacturing of building structures and equipment, metal materials often require passivation treatment to improve their corrosion resistance and service life. For example, steel structures, pipelines, etc. can be treated with passivation to prevent corrosion.

4) Aerospace field: In the manufacturing process of aerospace vehicles, metal materials need to have good corrosion resistance and wear resistance. Therefore, passivation treatment has important application value in this field, which can improve the service life and safety performance of aircraft, rockets, etc.

Different passivation treatment methods have wide applications in different application fields. In practical applications, appropriate passivation treatment methods should be selected based on the characteristics and specific requirements of metal materials to achieve the best results.