The Science of Stopping Rust: Choosing the Right Zinc Primer

Sacrificial vs. Barrier Protection

A zinc-rich primer is more than a coating—it is an engineered, sacrificial system. When the coating contains >80% metallic zinc by weight, it becomes conductive and sacrifices itself before the structural steel corrodes. Barrier primers, by contrast, rely purely on film build to keep oxygen and moisture away from the substrate.

Asset owners should evaluate the service environment: immersion, splash zones, or atmospheric C5 locations almost always warrant a zinc-rich epoxy or inorganic zinc primer beneath the build-coat system.