Application principle of rust inhibitor liquid

The application principle of a rust inhibitor liquid is based on preventing or slowing down the oxidation and corrosion of metals, typically iron and steel. Rust inhibitors achieve this by forming a protective barrier or neutralizing the factors that promote corrosion. Here are the key principles of how they work:

1. Barrier Formation:

Film Formation: Rust inhibitors create a thin, protective film or coating on the metal surface, which blocks moisture, oxygen, and corrosive agents (such as chloride ions) from reaching the metal. This layer can be made of oils, waxes, or other chemicals that resist water and air exposure.

Hydrophobicity: Many rust inhibitors contain hydrophobic (water-repellent) compounds, which ensure that water is repelled from the metal surface, reducing the chances of oxidation.

2. Chemical Passivation:

Passivating Agents: Some rust inhibitors contain passivating chemicals that react with the metal surface to form a passive, stable layer (e.g., iron oxide) that prevents further corrosion. This method effectively "inactivates" the surface, making it less reactive to oxygen and moisture.

Neutralizing Acids: Certain rust inhibitors neutralize acids that could accelerate corrosion. They may adjust the pH of the environment to make it less conducive to rust formation.

3. Chelation of Metal Ions:

Chelating Agents: Some rust inhibitors include chelating agents, which bind to metal ions such as iron (Fe²⁺ or Fe³⁺) and prevent them from participating in oxidation reactions that lead to rust formation.

4. Electrochemical Inhibition:

Cathodic Inhibitors: These inhibitors work by reducing the cathodic reaction rate (oxygen reduction or hydrogen evolution) that occurs during the corrosion process, which decreases the overall corrosion rate.

Anodic Inhibitors: Anodic inhibitors reduce the anodic reaction rate (metal oxidation), forming an adherent oxide layer that protects the metal surface.

5. Volatile Corrosion Inhibitors (VCIs):

VCIs are compounds that release protective vapors, which condense on metal surfaces and form a protective molecular layer. These are commonly used in enclosed environments such as packaging materials to protect metal parts during storage or transport.

6. Polymeric Additives:

Some rust inhibitors contain polymers that bind to the metal surface, creating a flexible and durable protective coating. These polymers can help the rust inhibitor adhere better and offer long-lasting protection.

Common Applications:

Industrial machinery: Protecting exposed metal parts and equipment from corrosion.

Automobile industry: Inhibitors are used to protect vehicle frames, engines, and parts from rust.

Marine equipment: Protecting ships, docks, and other structures exposed to saline environments.

Metalworking fluids: Added to coolants, lubricants, or cutting fluids to prevent rust formation during machining and storage.

In summary, rust inhibitors work by creating a protective barrier, chemically passivating the metal, or inhibiting the electrochemical reactions that lead to rust formation, thereby extending the lifespan of metal components and equipment.