Example of coating failures: Common causes and prevention

Coatings are essential for protecting surfaces from corrosion, wear, and environmental damage. However, when coatings fail, they can lead to costly repairs, structural damage, and safety hazards.

For those looking for an example of coating failures, this guide explores common types of failures, their causes, and how to prevent them.

Understanding coating failures is crucial for industries such as construction, automotive, marine, and manufacturing, as well as for individuals maintaining their homes and lifestyle choices that involve surface protection and aesthetics.

What is coating failure?

Coating failure occurs when a protective or decorative layer does not perform as expected, leading to peeling, cracking, blistering, or corrosion.

Failures can result from improper application, environmental exposure, material incompatibility, or poor surface preparation. Identifying the root cause of coating failure is essential for implementing effective solutions.

Example of coating failures and their causes

Here are some examples of coating failures and their causes:

1. Peeling and flaking

Peeling and flaking occur when a coating loses adhesion to the substrate or underlying layer. This failure can expose the material to environmental elements, leading to deterioration.

Causes:

• Inadequate surface preparation (dirt, grease, or rust remaining on the surface)
• Poor adhesion due to improper primer selection
• Application in humid or wet conditions
• Using incompatible coatings over existing layers

Prevention:

• Properly clean and prepare the surface before applying coatings
• Use appropriate primers and ensure compatibility between layers
• Follow recommended application conditions for temperature and humidity

2. Blistering

Blistering appears as raised bubbles on the coating surface, often caused by trapped moisture, air, or contaminants beneath the coating. These bubbles can eventually burst, leading to further degradation.

Causes:

• Moisture trapped under the coating due to high humidity during application
• Application over an unclean or damp surface
• Excessive coating thickness prevents proper drying
• Heat exposure causes expansion and pressure buildup

Prevention:

• Ensure the surface is completely dry before application
• Apply coatings in controlled temperature and humidity conditions
• Avoid excessive thickness and allow proper drying time between layers

3. Cracking and crazing

Cracking occurs when a coating becomes brittle and develops fractures, often due to aging or stress. Crazing refers to fine cracks that resemble a web-like pattern.

Causes:

• Application of an overly thick coating layer
• Incompatible materials cause stress on the surface
• Exposure to extreme temperatures, leading to expansion and contraction
• Natural aging and UV degradation weaken the coating

Prevention:

• Apply coatings in the recommended thickness to prevent excessive stress
• Choose flexible coatings that can withstand temperature fluctuations
• Use UV-resistant coatings for surfaces exposed to sunlight

4. Discoloration and fading

Discoloration and fading reduce the aesthetic appeal of a coating and may indicate underlying degradation. It commonly affects outdoor surfaces exposed to sunlight and harsh weather conditions.

Causes:

• UV radiation breaks down pigments in the coating
• Chemical exposure altering the coating’s color and composition
• Use of low-quality or non-UV-resistant coatings
• Inconsistent mixing of coating components during application

Prevention:

• Use UV-resistant coatings with high-quality pigments
• Avoid exposure to harsh chemicals that can cause discoloration
• Properly mix coatings before application to ensure uniformity

5. Corrosion undercoating

Corrosion under coatings occurs when water or chemicals penetrate beneath the protective layer, leading to rust and structural damage.

Causes:

• Inadequate surface preparation, leaving rust or contaminants on metal surfaces
• Coating damage due to mechanical impact or wear
• Permeability of the coating allows moisture intrusion
• Poor edge coverage, leaving unprotected areas exposed

Prevention:

• Ensure proper surface preparation, including rust removal and priming
• Apply coatings with sufficient thickness and edge coverage
• Use corrosion-resistant coatings for high-risk environments

6. Adhesion failure

Adhesion failure happens when a coating does not bond properly to the substrate, leading to premature detachment.

Causes:

• Surface contamination from oil, grease, or dust
• Incompatibility between different coating layers
• Insufficient curing or drying time before applying additional coats
• Application at extreme temperatures

Prevention:

• Clean and degrease surfaces thoroughly before coating application
• Use compatible primers and coatings designed for the substrate
• Allow adequate curing time between layers

How to prevent coating failures

Preventing coating failures requires proper planning, application, and maintenance. Key steps include:

1. Proper surface preparation: Cleaning, sanding, and priming ensure strong adhesion.
2. Choosing the right coating: Selecting coatings designed for specific environmental conditions improves durability.
3. Following manufacturer guidelines: Adhering to application instructions, including recommended temperature and humidity levels, prevents application issues.
4. Applying the right thickness: Too much or too little coating can lead to performance issues. Use the recommended thickness for optimal results.
5. Regular inspections and maintenance: Routine checks help identify early signs of failure and allow for timely repairs.

Final thoughts

For those seeking an example of coating failures, issues like peeling, blistering, cracking, and corrosion highlight the importance of proper application and maintenance.

Understanding the causes of coating failures helps industries take preventive measures to enhance durability and performance.

By following best practices in surface preparation, material selection, and application techniques, coatings can provide long-lasting protection and aesthetic appeal.