Which of the following describes the term 'Blistering' in coating failure?

Blistering in coating failure is primarily characterized by the formation of bubbles, which occur when solvents or moisture become trapped beneath the surface of the coating. This situation often arises due to improper application techniques, such as excessive film thickness or inadequate drying time, which allows solvents to be unable to escape during the curing process. As these solvents vaporize, they create pressure that lifts the coating from the substrate or from itself, resulting in visible bubbles or blisters.

The other choices indicate different types of coating failures. The first choice refers to partial adhesion loss, which leads to surface peeling but does not involve the formation of bubbles. The third choice highlights color change due to UV exposure, indicating a different failure mechanism relating to degradation rather than blistering. Meanwhile, the fourth choice describes surface roughness from contamination, which results in an uneven texture rather than bubble formation. Understanding these differences is crucial for identifying specific coating issues and applying appropriate remediation strategies.