Axxanol™ 718-ESS vs. Conformal Coatings: Choosing the Right Corrosion Protection Solution

Corrosion protection is critical in electrical and electronic applications. Moisture, contaminants, and environmental exposure can quickly damage sensitive circuits and components. Two common approaches used to protect electronics from corrosion include conformal coatings and ZERUST® Axxanol™ 718-ESS, a multi-metal electrical corrosion inhibitor spray. Conformal coatings create a thin polymer barrier over electronic assemblies, while Axxanol™ 718-ESS forms a corrosion-inhibiting protective layer on metal surfaces. Each method offers advantages depending on the application environment, maintenance requirements, and stage of the product lifecycle.

Understanding how conformal coatings compare with Axxanol™ 718-ESS can help engineers and maintenance teams select the most effective corrosion protection strategy.

Understanding Conformal Coatings for Electronics Protection

Conformal coatings have long been used in the electronics industry to protect printed circuit boards and assemblies from moisture, chemicals, and airborne contaminants.

These coatings form a thin protective film that follows the contours of electronic components. When properly applied, conformal coatings help isolate circuitry from environmental exposure.

However, several factors must be carefully controlled to ensure reliable performance.

Application Methods for Conformal Coatings

Original equipment manufacturers commonly apply conformal coatings during the electronics manufacturing process.

Typical application methods include:

• Brush coating
• Spray coating
• Dip coating

More specialized processes, such as vacuum deposition, may also be used for certain coatings, although these methods are less common in commercial electronics due to higher cost and complexity.

Surface Preparation Requirements for Conformal Coatings

Conformal coatings require extremely clean surfaces for proper adhesion.

If contamination remains on the circuit board before application, the coating may fail prematurely. Poor preparation can lead to:

• Adhesion loss
• Osmotic blistering
• Pinholes in the coating film
• Moisture penetration that leads to corrosion

For this reason, electronics manufacturers often implement strict cleaning and inspection procedures before applying conformal coatings.

Mechanical Properties of Conformal Coatings

Conformal coatings are designed to remain flexible while resisting environmental stress.

High mechanical strength is usually unnecessary and may even be harmful. Rigid coatings can create stress on sensitive electronic components and potentially cause:

• Component malfunction
• Cracking of the coating layer
• Delamination from the surface

Flexibility helps the coating withstand vibration, thermal expansion, and mechanical shock.

Glass Transition Temperature Considerationsfor Conformal Coatings

Traditional conformal coatings often have a glass transition temperature (Tg) in the range of 10 to 20°C (50 to 68°F).

At temperatures near or below this range, coatings may become brittle or lose flexibility. This can present challenges in electronics exposed to cold environments or temperature cycling.

For example:

• Coatings may become rigid and crack when exposed to low temperatures.
• Thermal cycling can cause expansion and contraction that stresses the coating layer.
• Brittle coatings may separate from surfaces and expose electronics to moisture.

Moisture Permeability for Conformal Coatings

Even when conformal coatings appear intact, some materials allow moisture to slowly diffuse through the coating layer.

For example, silicone conformal coatings are hydrophobic but can still permit moisture migration through defects or micro-permeable areas. Over time, this moisture exposure may allow corrosion to develop on exposed metal surfaces.

Key considerations include:

• Microscopic defects can allow moisture to penetrate the protective layer.
• Long-term humidity exposure may gradually increase corrosion risk.
• Moisture trapped under the coating can accelerate localized corrosion.

Understanding ZERUST® Axxanol™ 718-ESS

ZERUST® Axxanol™ 718-ESS provides an alternative approach to corrosion protection for electrical and electronic systems.

Rather than forming a rigid polymer film like conformal coatings, Axxanol™ 718-ESS creates a corrosion-inhibiting protective layer that shields metal surfaces from moisture and corrosive contaminants.

This makes it particularly useful for field maintenance, aftermarket corrosion protection, and situations where traditional conformal coatings may not be practical.

Field Application Advantages

One major advantage of Axxanol™ 718-ESS is its ease of application.

Technicians can apply the spray directly in the field without the specialized equipment often required for conformal coatings. It can also be applied to surfaces that may contain light oils or residues.

This flexibility makes Axxanol™ 718-ESS useful for:

• Electrical cabinets
• Control panels
• Connectors and terminals
• Industrial electronics exposed to humid environments

Performance in Humid Environments

Unlike many conformal coatings, Axxanol™ 718-ESS can be applied even when humidity levels are elevated.

The formulation displaces moisture and forms a protective barrier that helps prevent corrosion in challenging environments.

This capability makes it particularly valuable for equipment exposed to:

• Outdoor conditions
• Marine or coastal environments
• Industrial humidity
• Condensation cycles

Stress-Free Protection for Electronics

Because Axxanol™ 718-ESS does not cure into a rigid coating, it does not introduce mechanical stress to sensitive electronic components.

This can reduce the risk of coating-related failures in assemblies where thermal expansion, vibration, or mechanical movement may occur.

This approach offers several advantages:

• Flexible protection that adapts to thermal expansion and vibration.
• No rigid film that can crack or delaminate from the surface.
• Reduced risk of coating stress affecting sensitive electronic components.

Temporary Corrosion Protection

Unlike conformal coatings, Axxanol™ 718-ESS functions as a temporary protective coating (TPC).

It provides effective corrosion protection but may require periodic reapplication depending on environmental exposure.

In contrast, conformal coatings are generally treated as permanent protective coatings (PPCs) applied during the manufacturing process.

Typical use cases include:

• Short to medium-term corrosion protection during storage or transport.
• Maintenance protection for electrical cabinets and field equipment.
• Interim corrosion protection before permanent coatings are applied.

Temperature Considerations

Axxanol™ 718-ESS performs well in electronics operating at temperatures up to approximately 80°C (176°F).

Higher temperatures may reduce the longevity of the protective film, so application conditions and service environment should always be considered during product selection.

When evaluating temperature limits:

• Elevated temperatures can gradually reduce the life of the protective layer.
• Equipment operating within recommended temperature limits maintains optimal corrosion protection.
• Periodic inspection helps confirm continued protection in high-temperature environments.

When to Use Conformal Coatings vs. Axxanol™ 718-ESS

ZERUST® Axxanol™ 718-ESS was not designed to replace conformal coatings in electronics manufacturing. Instead, it complements them by addressing situations where traditional coatings may not be practical.

For example:

Axxanol™ 718-ESS is ideal for:

• Field maintenance of electrical systems
• Aftermarket corrosion protection
• Temporary corrosion protection during storage or transport
• Protecting connectors, terminals, and exposed electrical contacts

Conformal coatings are typically used for:

• Factory-applied protection during electronics manufacturing
• Long-term protection of circuit boards in sealed devices
• Applications requiring a permanent protective layer

In some situations, Axxanol™ 718-ESS can even support repair or maintenance of systems that already use conformal coatings, particularly when localized corrosion protection is needed.

Choosing the Right Corrosion Protection Strategy

Selecting between conformal coatings and Axxanol™ 718-ESS depends on several factors, including the stage of the product lifecycle, the environmental conditions, and the maintenance strategy for the equipment.

Manufacturers may rely on conformal coatings during production, while maintenance teams often benefit from the flexibility and ease of application offered by Axxanol™ 718-ESS.

ZERUST® corrosion specialists can help evaluate your application environment, corrosion risks, and equipment requirements to determine the most effective protection strategy.

Our team can visit your facility, review your current corrosion management practices, and recommend products and procedures that improve reliability while reducing maintenance costs.

With the right corrosion protection approach, electronics and electrical systems can operate reliably even in challenging environments.

Tom White

Tom White is the Marketing Manager at ZERUST®, bringing almost a decade of expertise in Vapor Corrosion Inhibitor (VCI) technologies and corrosion prevention solutions. He leads strategic marketing initiatives that showcase ZERUST®’s global product portfolio, from sustainable VCI packaging films to advanced rust preventatives and cleaners. Tom is deeply involved in product launches, trade show planning, digital marketing, and customer engagement, ensuring that ZERUST®’s innovative solutions reach the right industries and decision-makers. With a strong focus on aligning technical expertise with customer needs, he helps drive the brand’s growth and strengthen its position as a leader in corrosion protection worldwide.

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