Zinc Phosphate

Zinc Phosphate Zn₃(PO₄)₂ is a highly effective white anticorrosive pigment used in paint and coating formulations to protect metal surfaces from corrosion. It is a fine white powder with excellent hiding power, strong adhesion, and high resistance to aggressive environments.

This zinc-based pigment is an environmentally friendly alternative to chromates and is widely used in anticorrosive coatings for steel, aluminum, and galvanized surfaces.

Applications

• Anticorrosive primers and enamels (including waterborne)
• Powder coatings
• Cold galvanizing systems
• Industrial coatings for machinery and steel structures

How zinc phosphate works

Due to its ability to interact with metal, zinc phosphate forms a passivating phosphate film.

The resulting film:

• Protects metal from oxygen and moisture
• Reduces electrochemical reaction rates
• Improves adhesion of subsequent coating layers

Dosage recommendations

The recommended dosage of zinc phosphate depends on the coating type:

• Epoxy primers: 15–25%
• Alkyd and acrylic systems: 10–20%
• Waterborne coatings: 5–12%
• Zinc dust combinations: 3–8%

Technical tips

• In water-based systems, pre-dispersing in binder or with surfactants is recommended
• Use milling or high-speed mixing for a stable suspension
• Can be combined with zinc dust, calcium phosphates, or organic inhibitors
• In powder coatings, added during mixing and dispersed in an extruder

Packing and storage

Zinc phosphate is supplied in 25 kg bags. Store in a dry, well-ventilated area, away from moisture.