Don't miss an insight. Subscribe to Corrosionpedia for free.


How and why should I measure the strength of a protective coating?

By Krystal Nanan | Last updated: January 20, 2023

Modern industrial processes continue to place heavy demands on tools, equipment and structures. As a result, the protective coatings used to shield these assets must be able to maintain their integrity, particularly in aggressive and challenging environments.

Coating strength is defined as the ability of the coating to withstand loading without a coating failure (e.g., peeling, adhesion loss, cracking, wrinkling, erosion, etc.). This property is a direct indicator of the effectiveness of the protection offered. If the coating does not possess enough strength to resist applied forces, then it can fail and put the asset at risk for severe corrosion. (Be sure to download our Coating Failures and Defects Guide.)

Coating strength is measured by several mechanical tests. These tests involve subjecting the coating to multiple load conditions while observing the coating's response. Various coating strength properties are measured using several tests methods, some of which include:

Hardness Test

Coating hardness measures the ability of the coating to withstand indentation or deformation from external forces (e.g., a sudden impact). This property is measured using several tools, including the Buchholz indentation, pendulum hardness and pencil hardness tests.

Abrasion Test

The abrasion test measures the coating's resistance to removal via scraping. This test determines the coating's ability to remain in place when rubbed against another surface. The Taber abrasion test and scrub abrasion test are most commonly used to measure this property.

Adhesion Test

The adhesion test, as its name implies, measures the quality of the bond between the coating and the substrate. If the coating lacks sufficient adhesion to the surface, it can peel or flake off, leaving the substrate exposed and vulnerable to corrosion. Coating adhesion tests include the pull-off adhesion test, the tape adhesion test and the crosscut adhesion test. (Learn more about adhesion testing in 4 Types of Tests that Measure the Strength of a Coating.)

Flexibility Test

When a coated material undergoes deformation, the coating needs to be able to deform likewise while maintaining its integrity. The most common way of measuring the flexibility of a coating is to bend a coated panel over a cylindrical or conical-shaped bar. If the coating is too brittle, it will develop cracks as a result of the bending.

Share this Q&A

  • Facebook
  • LinkedIn
  • Twitter


Preventative Coatings Inspection Procedures Paints and Plastics Coatings Metallic and Ceramic Coatings Corrosion Prevention Tools Physical Property Measurement General Procedures Coatings Inspection / Monitoring

Written by Krystal Nanan | Civil Engineer

Profile Picture of Krystal Nanan
Krystal is a civil engineer and project manager with an MSc in Construction Engineering and Management. Her experience includes the project management of major infrastructure projects, construction supervision, and the design of various infrastructure elements including roadway, pavement, traffic safety elements and drainage. Krystal is also a published author with the Transportation Research Board in Washington, D.C.

More Q&As from our experts

Related Terms

Related Articles

Term of the Day


Tungsten refers to a naturally occurring metal element with the chemical symbol W and an atomic number of 74. Tungsten has a...
Read Full Term

Don't miss the latest corrosion content from Corrosionpedia!

Subscribe to our newsletter to get expert advice and top insights on corrosion science, mitigation and prevention. We create world-leading educational content about corrosion and how to preserve the integrity of the world’s infrastructure and assets.

Go back to top