What is one function of a barrier coating?

A barrier coating is primarily designed to prevent various environmental elements from reaching the substrate it protects. One of its main functions is to act as a protective layer that inhibits oxidation, which can occur when metal surfaces are exposed to moisture and oxygen. By preventing oxidation, the barrier coating extends the life of the substrate and maintains its structural integrity.

The other options, while they illustrate concepts related to coatings, do not align with the primary purpose of a barrier coating. Allowing water vapor to pass could defeat the purpose of preventing corrosion and deterioration. Acting as a colorant addresses aesthetic considerations without providing the protective qualities essential to a barrier coating. Enhancing surface texture pertains to the physical feel or appearance of a surface, rather than its protective capability against environmental factors.