Zinc Phosphate Coating in Corrosion Control - A Review

Due to its wide areas of applications, ready availability and affordability, mild steel has become a very versatile metal in the industry, but it is usually exposed to different environments that can corrode it, thereby affecting its properties and performance.Hence, effective metal corrosion control is required before or during mild steel application.Zn₃(PO₄)₂ coating is a preferred method for surface treatment and finishing of both ferrous and non-ferrous metals, being highly regarded for its efficiency, rapid operation and ability to provide outstanding corrosion and wear resistance, adhesion and lubricative properties.In this review, components of Zn₃(PO₄)₂ bath, its detailed process, adsorption mechanism on metal surfaces, applications, thermodynamic and kinetic properties, are considered.