Zinc Aluminum Phosphate ZAP-10 (Chrome-Free Anticorrosion Pigment)

Zinc chromate (Cr6+) provides superior corrosion protection through strong oxidizing action that repassivates steel scratches. However, Cr6+ is CMR (carcinogenic, mutagenic, reprotoxic) and banned for most applications under EU REACH. Zinc aluminum phosphate (ZAP) inhibits corrosion through phosphate ion adsorption and zinc passivation of anodic sites—a milder but environmentally acceptable mechanism. In severe service (marine, pipeline), ZAP primers need thicker film build and may require top-coat barrier support to match chromate performance. For mild-to-moderate industrial exposure, ZAP-based primers provide equivalent 5–10 year service life.