Prevent Rust with Volatile Corrosion Inhibitors (VCIs)

Prevent Rust with Volatile Corrosion Inhibitors (VCIs)
Published On:April 27, 2018 Revised On:July 1, 2023

What is a Volatile Corrosion Inhibitor?

Volatile Corrosion Inhibitors (VCIs) effectively prevent rust on metal surfaces by releasing molecules that create a protective layer, thus delaying corrosion. Unlike traditional inhibitor coatings, VCIs possess diffusing properties, enabling them to absorb acid gases and offer a physical barrier.

This versatility makes them highly effective in a wide range of applications. To ensure proper use of VCI products for rust prevention, enclosing metal parts with VCI products, minimising airflow to enhance their effectiveness, and only removing the VCI protective layer when necessary.

Definition of VCI

A volatile corrosion inhibitor, commonly known as VCI, is a chemical substance that prevents the corrosion of metal surfaces by forming a protective layer on them. It releases molecules that evaporate into the surrounding atmosphere, creating a rust-preventing shield around metallic components. This organic compound vaporises and diffuses in the environment to reach all surfaces and crevices of metal objects, providing continuous protection against corrosion.

The properties of VCI emit an invisible protective layer which is non-reactive towards metals or chemicals and resists moisture, salt deposits, acid gases and UV rays. VCIs work in contact with the surface and do not leave any residue or require cleaning before use.

Minimising airflow when using VCI products is essential since proper application relies on constant exposure to target metals. This involves enclosing metal parts using suitable materials and adequate sealing methods to prevent air from seeping through interfaces between the protective layer material and metallic surfaces. Proper storage with appropriate labelling will also clarify usage instructions for other operators.

VCI technology provides a cost-effective solution compared to other methods that typically rely on frequent applications requiring disassembly, cleaning, reassembly and crane time resulting in downtime during assembly operations.

How does VCI prevent corrosion?

Volatile corrosion inhibitors (VCI) prevent corrosion by producing a protective layer on the surface of metals. This layer creates a barrier between the metal and its environment, inhibiting the electrochemical reactions that cause corrosion. The VCI molecules evaporate into the air above the metal and diffuse to all areas where moisture may accumulate.

VCI prevents corrosion and can form a molecular bond with the surface of metals for long-lasting effectiveness. This, combined with its non-toxic nature, makes it an effective and safe means of preventing rust across various industries ranging from automotive, military, marine, and aerospace to offshore drilling.

Advantages of Volatile Corrosion Inhibitors

Volatile corrosion inhibitor (VCI) diffuses in a specific pattern to form a protective layer on metal surfaces, preventing corrosion. The diffusing properties of VCI make it incredibly effective in rust prevention by creating an invisible barrier around metal parts enclosed within VCI products. Additionally, VCIs can be combined with desiccants to create further protection from corrosive environments.

Properties Details
Chemical Nature of Inhibitors VCI consists of anticorrosive compounds, which inhibit the transfer of electrons and prevent corrosion.
Molecular Weight Distribution VCI has a low molecular weight distribution, which enables it to diffuse over long distances and reach inaccessible areas.
Diffusion Coefficient The diffusion coefficient is the proportionality constant between the concentration gradient and the flux. VCIs have high diffusion coefficients that enhance their effectiveness in preventing corrosion.

Types of VCI solutions

Non-ferrous VCI Film

Non-ferrous VCI Film is a high-quality product with effective rust prevention benefits.

Properties Details
Material Polyethene
VCI molecules per sq/ft 43 grams
Film thickness in mm 0.0025 – 0.0228
Corrosion protection period (if stored sealed) Up to 5 years
Effective temperature range Between -18°C and +49°C

The film is unique in its composition and demonstrates superior penetrating abilities that enable it to prevent corrosion more effectively than traditional coatings. To maximise the effectiveness of the Non-ferrous VCI film, metal parts should be appropriately cleaned and free of contaminants before being encased with this protective barrier.

VCI Emitters

VCI Emitters have excellent diffusing properties and can protect metal parts from corrosion inside and outside enclosed spaces. They are specifically suitable for applications with limited access to all surfaces or areas that need protection. Additionally, the acid gas absorbing chemicals within the capsules neutralises corrosive gases in the surrounding air, further protecting the metal from oxidation.

Once the capsules’ contents vaporise, they form an invisible barrier between the metal surface and external factors such as moisture and oxygen. This barrier protects against corrosion without altering the part’s mechanical or electrical properties.

VCI Bags

Property Details
Type Flexible packaging bag
Material Compatibility Metals, Multi-Metals
Rust Prevention Duration Up to 5 years
Storage Environment Indoor, Outdoor
Temperature Range <50°F to >90°F

VCI bags are compatible with multiple metals and can prevent rust for up to 5 years. It can be stored indoors and outdoors from below 50°F to above 90°F. Additionally, this product offers an efficient and cost-effective solution for preventing corrosion in challenging environments.

Poly Coated Reinforced VCI Paper

Property Description
Composition Polyethene-coated reinforced paper
VCIs present Yes, Multi-Metal VCI Nanotechnology
Protection period Up to two years
Features Tear and puncture-resistant, water-resistant, and airtight seal

The reinforced VCI paper has tear and puncture-resistant properties due to its polyethene coating. It forms an airtight seal around metal parts and can prevent damage from water.

VCI Kraft Paper

Properties Details
VCI Type Multi-metal
Paper Weight (lbs) 30, 35, 40 or 60 lb.
Paper Color Natural Kraft Brown Color
Certifications RoHS compliant
No nitrites, no chromates
NSF certified for food-grade applications
MIL-PRF-3420-H qualified
Free from silicone
  • Metalworking and fabrication industry applications, including shipbuilding, military equipment preservation, transmission and engine component packaging and pipeline packaging solutions.
Sizes Available
  • 36″ x 200yds or custom slit width or length available in roll stock format
  • Die-cut sheets
  • Fabricated bags
  • Custom-size short rolls
  • Shrouds

VCI Kraft Paper is RoHS compliant and contains no nitrites or chromates. It is NSF certified for food-grade applications and MIL-PRF-3420-H qualified. The paper is free from silicone and can be used in various applications such as the metalworking and fabrication industry, including shipbuilding, military equipment preservation, transmission and engine component packaging, and pipeline packaging solutions.

Protecting metal surfaces from rust is essential for product longevity. VCI Kraft Paper provides a cost-effective solution without needing messy oils and coatings that may require additional cleaning before further processing.

How to use VCI products for rust prevention

Enclosing metal parts with VCI packaging solutions is a cost-effective and versatile method for preventing rust. There are numerous advantages of using VCI products over traditional inhibitor coatings. Below are the six key points to consider when enclosing metal parts with VCI products:

  • Use high-quality VCI packaging material to avoid corrosion.
  • Wrap tightly and seal all openings in the package so no moisture or dust can enter.
  • Clean the metal parts before placing them in the package, as dirt or grease may impede VCI penetration.
  • Choose a VCI product that can suitably protect against any atmospheric corrosion, irrespective of geographical location.
  • Ensure the package containing metal parts is warm, dry and reasonably protected from sunlight.

It’s essential to minimise airflow, as moving air can carry away vapour molecules of VCI chemicals. After enclosing the metal parts, store them in a dry place or follow recommendations for storage life specified on the label.

Importance of minimising airflow

It minimises airflow to ensure the effective prevention of rust using VCI products. This is because airflow can compromise the protective layer formed by the VCI product and expose the metal surface to oxidation. Thus, enclosing the metal parts with VCI products is crucial to minimise any exposure to air.

In addition to enclosing metal parts with VCI products, ensuring the packaging material is airtight and adequately sealed is also essential. Any openings or gaps in the packaging can allow air circulation and reduce the effectiveness of VCI protection.

Minimising airflow during storage or shipment of metal parts by using vacuum packaging. By removing all air from the packaging, there will be no chance of oxygen penetrating through any gaps or openings, thus ensuring maximum rust prevention.

Removal of the VCI protective layer

After the metal parts have been enclosed in VCI products, the protective layer of VCI must be removed before use. This can be done by wiping or washing off the VCI chemical residue with a mild solvent or water-based cleaner.

After removing the VCI protective layer, it is essential to re-apply it if the parts will be stored or put in transit for an extended period. This ensures no exposure to air and moisture, leading to rust formation.


Volatile Corrosion Inhibitor (VCI) is a highly effective and versatile method for preventing rust on metal surfaces. It involves using a VCI compound that forms a protective layer, effectively blocking water and oxygen to halt rust formation. This cost-effective technique provides long-term protection, even for hard-to-reach areas.

The applications of VCI are extensive, ranging from rust prevention during equipment transport to the extended storage of machinery. The method does not impact equipment performance and requires no pre-cleaning.

Compared to other rust prevention methods, using VCI saves time and money. It offers unique advantages, such as its effectiveness on various metals like aluminium and copper and its durability in different environmental conditions.

Overall, VCI presents a cost-effective and versatile solution for preventing rust and prolonging the lifespan of machinery. By opting for this method, individuals can protect metal surfaces, save money, and contribute to environmental sustainability.