What is the function of sacrificial pigments in coatings?

Sacrificial pigments in coatings are specifically designed to corrode before the underlying substrate, such as metal surfaces. This function is crucial because it acts as a protective measure against corrosion. When exposed to environmental elements, these pigments will oxidize and deteriorate in place of the substrate, thus prolonging the life of the coating and the material beneath it. This process ensures that the substrate is preserved, preventing structural damage and the need for costly repairs or replacements.

While the other functions listed, like improving adhesion or enhancing color, are important aspects of coatings, they don't directly relate to the primary function of sacrificial pigments. The enhancement of opacity also does not pertain to their sacrificial nature. Therefore, the role of these pigments is uniquely to protect the substrate by serving as a buffer against corrosion, making corrosion prevention their key performance attribute.