Understanding Volatile Corrosion Inhibitors & How They Protect Metals


Metals are widely used in various industries due to their strength, durability, and versatility. However, they are susceptible to corrosion, which can significantly compromise their integrity and functionality. To combat this issue, researchers have developed a range of corrosion inhibitors, including volatile corrosion inhibitors (VCIs). In this article, we will delve into the world of volatile corrosion inhibitors, exploring what they are, how they work, and their effectiveness in protecting metals.

Table of Contents

  1. What are Volatile Corrosion Inhibitors?
  2. How Do Volatile Corrosion Inhibitors Work?
  3. Types of Volatile Corrosion Inhibitors
  4. Advantages of Using Volatile Corrosion Inhibitors
  5. Applications of Volatile Corrosion Inhibitors
  6. Factors to Consider When Using Volatile Corrosion Inhibitors
  7. Best Practices for Applying Volatile Corrosion Inhibitors
  8. Challenges and Limitations of Volatile Corrosion Inhibitors
  9. Future Developments in Volatile Corrosion Inhibitors
  10. Conclusion
  11. FAQs
  1. What are Volatile Corrosion Inhibitors?

Volatile Corrosion Inhibitors (VCIs) are a class of chemical compounds that are designed to protect metals from corrosion. These compounds release vapors that form a thin protective layer on the metal surface, creating a barrier against moisture, oxygen, and other corrosive elements. The vapors emitted by VCIs are able to diffuse throughout an enclosed space, ensuring comprehensive protection for the metal parts within that space.

  1. How Do Volatile Corrosion Inhibitors Work?

When VCIs are exposed to the metal surface, they undergo a process known as adsorption. During adsorption, the VCI molecules are attracted to the metal surface and adhere to it, forming a protective layer. This layer acts as a physical and chemical barrier, inhibiting the corrosion process. The vapors emitted by the VCIs continuously replenish the protective layer, ensuring long-lasting corrosion protection.

  1. Types of Volatile Corrosion Inhibitors

There are various types of volatile corrosion inhibitors available in the market, each with its specific characteristics and applications. Some common types include:

3.1 Vapor Phase Inhibitors (VPIs)

Vapor Phase Inhibitors, also known as vapor corrosion inhibitors (VCIs), are the most widely used type of VCIs. These inhibitors release vapor molecules that form a protective layer on the metal surface, even in hard-to-reach areas. VPIs are particularly effective for long-term storage or shipping of metal components.

3.2 Contact Inhibitors

Contact inhibitors, as the name suggests, require direct contact with the metal surface to provide corrosion protection. These inhibitors are often applied as coatings, sprays, or oils. They are commonly used for short-term protection or in situations where continuous vapor emission is not feasible.

3.3 Multimetal VCIs

Multimetal VCIs are specifically formulated to protect multiple types of metals from corrosion. They are designed to be effective on a wide range of metal alloys, making them versatile for industries that deal with various metal components.

  1. Advantages of Using Volatile Corrosion Inhibitors

Using volatile corrosion inhibitors offers several advantages in the realm of metal protection. Some key advantages include:

  • Easy Application: VCIs can be applied through simple methods like packaging, spraying, or coating, making the process convenient and time-saving.
  • Cost-Effective: Compared to traditional corrosion protection methods, VCIs provide a cost-effective solution by reducing the need for complex coatings or constant maintenance.
  • Non-Destructive: VCIs do not alter the physical or mechanical properties of the metal, ensuring that the protected components remain unchanged and fully functional.
  • Environmentally Friendly: Many VCIs are non-toxic and biodegradable, making them environmentally friendly alternatives to other corrosion inhibitors.
  1. Applications of Volatile Corrosion Inhibitors

Volatile corrosion inhibitors find application in various industries where metal protection is crucial. Some common applications include:

  • Automotive: VCIs are used to protect automotive parts during transportation, storage, and assembly, preventing corrosion damage.
  • Aerospace: In the aerospace industry, VCIs are utilized to safeguard critical components, such as aircraft engines and avionics, from corrosion.
  • Manufacturing: VCIs are employed to protect metal parts, machinery, and equipment during production, storage, and shipping.
  • Military and Defense: VCIs play a vital role in preserving military equipment, weapons, and infrastructure, ensuring their readiness and longevity.
  • Electronics: Volatile corrosion inhibitors are used in the electronics industry to prevent corrosion damage to circuit boards, connectors, and other metal components.
  1. Factors to Consider When Using Volatile Corrosion Inhibitors

While VCIs offer effective corrosion protection, several factors should be considered for optimal results:

  • Compatibility: Ensure that the chosen VCI is compatible with the metal or alloy being protected. Some VCIs may not be suitable for certain metals, leading to reduced effectiveness.
  • Environmental Conditions: The surrounding environment, including temperature, humidity, and exposure to chemicals, can affect the performance of VCIs. Consider these factors when selecting and applying VCIs.
  • Duration of Protection: Different VCIs have varying longevity. Consider the required duration of corrosion protection and choose the appropriate VCI accordingly.
  1. Best Practices for Applying Volatile Corrosion Inhibitors

To maximize the effectiveness of VCIs, it is important to follow best practices during application:

  • Clean Surfaces: Ensure that the metal surfaces are thoroughly cleaned before applying VCIs to remove any dirt, grease, or existing corrosion.
  • Adequate Coverage: Apply VCIs evenly and ensure complete coverage of all metal surfaces to create a uniform protective layer.
  • Proper Packaging: When using VCIs for storage or shipping, choose appropriate packaging materials that facilitate vapor distribution while protecting the metal from physical damage.
  1. Challenges and Limitations of Volatile Corrosion Inhibitors

While VCIs offer significant benefits, they also come with certain challenges and limitations:

  • Limited Reach: VCIs primarily provide protection in enclosed spaces, making it challenging to protect large or open areas.
  • Sensitivity to Removal: VCIs can be removed or compromised by excessive handling, cleaning agents, or prolonged exposure to harsh environmental conditions.
  • Compatibility Issues: Certain metals may react with specific VCIs, leading to reduced effectiveness or even adverse reactions.
  • Shelf Life: VCIs have a limited shelf life, and their effectiveness diminishes over time. Regular inspection and replacement of VCIs are necessary to ensure continuous protection.
  1. Future Developments in Volatile Corrosion Inhibitors

Researchers are continuously exploring advancements in volatile corrosion inhibitors to overcome existing limitations and enhance their performance. Some areas of focus for future developments include:

  • Extended Longevity: Developing VCIs with extended protection duration to reduce the need for frequent replacement.
  • Nanotechnology: Integrating nanotechnology into VCI formulations to enhance their effectiveness and precision.
  • Environmentally Friendly Formulations: Emphasizing the development of VCIs that are eco-friendly, biodegradable, and pose minimal risk to human health.


Volatile corrosion inhibitors are valuable assets in the battle against corrosion in the world of metals. Their ability to create a protective layer and inhibit the corrosive process makes them indispensable for various industries. By understanding the different types of VCIs, their applications, and the factors to consider during their usage, industries can effectively safeguard their metal components and prolong their lifespan.


Q1: Are volatile corrosion inhibitors safe for human health? A1: Yes, many volatile corrosion inhibitors are non-toxic and pose minimal risk to human health when used as directed.

Q2: Can volatile corrosion inhibitors be used for outdoor metal protection? A2: While VCIs are primarily effective in enclosed spaces, certain formulations are designed for outdoor use and can provide protection in outdoor environments.

Q3: Do volatile corrosion inhibitors require reapplication over time? A3: The longevity of VCIs varies depending on the formulation. Some may require reapplication after a certain period to maintain optimum protection.

Q4: Can volatile corrosion inhibitors be used on painted or coated surfaces? A4: It is essential to check the compatibility of VCIs with painted or coated surfaces. Some VCIs may interact with paints or coatings, affecting their performance.

Q5: Can volatile corrosion inhibitors be used on different types of metals? A5: Yes, there are VCIs specifically designed for multimetal protection, making them suitable for a wide range of metal alloys.