Table of Contents
- How vapor corrosion inhibition works
- VCI forms and applications
- Choosing VCI by cargo type
- VCI for ferrous and multi-metal goods
- Correct use and combining with desiccant
- Common mistakes
- Related articles
- Frequently asked questions
- Contact ICD Vietnam
- VCI Product Types and How to Choose
- VCI vs Traditional Anti-Corrosion Methods
Reviewed and updated by ICD - Week 38/2026
VCI (Volatile Corrosion Inhibitor) is an anti-rust chemical impregnated into packaging film, paper, bags or tablets. Once sealed, the VCI vaporises and deposits a protective molecular layer on metal surfaces, blocking the moisture and oxygen that cause rust - with no oils or greases and no cleaning when opened. It is a common rust-prevention solution for metal parts and machinery in storage and export.
How vapor corrosion inhibition works
VCI molecules have enough vapor pressure to leave the packaging material, fill the enclosed space and adsorb onto metal as an ultra-thin, invisible monomolecular film. This layer repels moisture and interrupts the electrochemical reaction that drives corrosion. A key advantage: the vapor reaches gaps, hidden corners and internal cavities that oils cannot coat; when opened, the VCI dissipates, leaving the metal clean and ready to use.
VCI forms and applications
| VCI form | Main application |
|---|---|
| VCI paper | Interleaving and wrapping machined parts, bearings, steel coils; separating metal from acidic carton/wood |
| VCI film / bags | Sealing parts, large machinery, container liners; anti-static grades for electronics |
| VCI powder | Dosed into empty cavities, tanks and large pipes by volume |
| VCI tablets / emitters | Placed in electrical cabinets, control boxes and tight spaces for local protection |
| VCI foam / oil | Cushioning plus rust protection; VCI oil for spraying or dipping parts |
Choosing VCI by cargo type
Small parts (bearings, screws, stampings) should use sealed VCI bags or film to create a stable-concentration environment. Large machinery with cavities (engines, cabinets, tanks, pipes) needs outer VCI film plus powder or tablets placed inside the cavities - because vapor struggles to diffuse deep into sealed cavities from an outer wrap alone. Sensitive electronics should use anti-static VCI bags.
VCI for ferrous and multi-metal goods
There are VCI types specific to ferrous metals (steel, cast iron) and multi-metal types that also protect non-ferrous metals such as aluminum, copper and zinc. Using the wrong type may be ineffective or react with non-ferrous metals, so choose the formula matching the metal you need to protect.
Correct use and combining with desiccant
A tight seal is critical: use a heat sealer or specialised tape for bags and film, because leaky packaging lets the vapor escape and lose effect. Metal surfaces must be dry and clean before sealing. For long sea voyages, combine desiccant to lower overall humidity - VCI and desiccant complement each other. Protection typically lasts 12-36 months depending on type and seal quality.
Common mistakes
First, leaky packaging, so parts still rust despite using VCI. Second, only wrapping a large machine’s exterior and forgetting powder or tablets inside the cavities, which stay damp and rust. Third, sealing while surfaces are still damp or oily. Fourth, using ferrous VCI on aluminum or copper goods. Fifth, opening to inspect and not resealing, letting the active agent escape.
Related articles
Frequently asked questions
How is VCI different from anti-rust oil?
VCI protects by vapor, reaching gaps and internal cavities, leaves no grease and needs no cleaning; oil only protects contact areas and must be removed before use.
Which metals can VCI protect?
There are ferrous types (steel, cast iron) and multi-metal types for aluminum, copper and zinc. Choose the formula matching the metal.
Why do parts still rust with VCI?
Usually leaky packaging lets the vapor escape, or a large machine is only wrapped outside without powder/tablets in the cavities.
How long does VCI protect?
Typically 12-36 months with a sealed package and dry, clean surfaces; add desiccant for long sea voyages.
Should VCI be used with desiccant?
Yes for sea freight: VCI lays an anti-rust vapor layer while desiccant lowers overall humidity - the two complement each other.
Contact ICD Vietnam
ICD Vietnam Industrial Manufacturing Co., Ltd - pallets, plastic crates, stretch film, forklifts and packaging solutions.
Hotline: 0983 797 186 / 090 345 9186
Email: sales@icdvietnam.com.vn | Zalo: Chat on Zalo
VCI Product Types and How to Choose
VCI packaging comes in several physical forms, each suited to a different metal type, part geometry or shipping scenario. Choosing the wrong form - for example, using a flat sheet when a sealed bag is needed - reduces effective protection and shortens corrosion-free shelf life well below the rated 2-5 years. The table below maps each VCI form to its protection range and the applications it handles best.
| VCI Form | Protection Range | Best For |
|---|---|---|
| VCI PE bag | Small to medium parts, sealed enclosure | Machined parts export, spare parts kitting |
| VCI paper | Wrapping irregular or complex shapes | Machined metal, flanges, castings |
| VCI film (shrink) | Large equipment, full surface coverage | Heavy machinery, engines, steel coils |
| VCI emitter | Enclosed space, air volume up to 1 m3 | Container shipping, toolboxes, cabinets |
| VCI foam | Contact and vapour protection combined | Sensitive electronics, PCB protection |
For export shipments where humidity and temperature fluctuate across multiple transit legs, VCI PE bags rated to MIL-PRF-3420 or DIN 55474 provide the most reliable baseline. Emitters are added when parts cannot be individually bagged but must share an enclosed container space.
VCI vs Traditional Anti-Corrosion Methods
Oil and grease have protected metal parts in transit for decades, but VCI technology offers three practical advantages that matter to modern production and logistics teams handling industrial packaging supplies.
- No degreasing step before use. Parts protected with VCI film or bags can go directly into assembly or further processing. Oil-coated parts require a solvent cleaning cycle that adds labour time, chemical cost and disposal requirements - typically 15 to 30 minutes per batch depending on part complexity.
- Cleaner handling throughout the supply chain. VCI vapour leaves no residue on protected metal surfaces. Warehouse staff, quality inspectors and end customers handle parts without contamination risk, reducing rework and complaint rates on outgoing shipments.
- Reusable packaging containers. Because VCI-treated bags and films are dry, the outer cartons, crates and pallets used to ship the parts remain clean and can be returned and reused without decontamination. With oil-based protection, packaging is often single-use due to contamination, which raises per-shipment materials cost.
The trade-off is that VCI protection depends on maintaining a sealed enclosure - any breach in the bag or film allows the protective vapour to escape and corrosion inhibition drops. For parts stored in open racks or environments with heavy air movement, a supplementary emitter or a more robust VCI film gauge (typically 100-150 micron) is recommended.
Reference
Volatile Corrosion Inhibitor (VCI) mechanism protecting metal surfaces - NACE International.
