BONDERITE® M-ZN - Zinc Phosphate Technology

There are three main steps in the pre-treatment of metals with a zinc phosphate conversion coating: Cleaning and activating of the metal surface, application of the conversion layer and sealing/post-passivation. The process coats the metal surface with a polycrystalline structure containing iron, manganese, nickel and zinc phosphates that provides excellent adhesion for powder paint, electrophoretic coatings or liquid paint and offers superior corrosion protection.

BONDERITE® has products for the three process steps; our long experience allows us to customize each process to meet your needs.

Process Summaries

Zinc phosphate conversion coating gives a high level of corrosion resistance and provides a perfect foundation for subsequent coating or painting. The BONDERITE® phosphate conversion coatings can be used on a wide range of metallic surfaces including galvanized steel, electrogalvanized steel, zinc-alloy-coated steel aluminium, zinc, cadmium, silver and tin.

The process has the ability to convert the metal surface into a non-metallic, polycrystalline coating containing iron, manganese, nickel and zinc phosphates. This coating provides high alkaline resistance and is preferred as a paint base offering superior adhesion and durability.

The HENKEL, tricationic phosphating process for steel, galvanised, alloyed coated (Zn/Ni) steel and aluminium (after bath-modification) generates a fine crystalline coating of manganese containing zinc phosphate. The crystalline layer has very good corrosion protection properties and is an excellent foundation for subsequent painting or organic coating. 

HENKEL supplies a range of BONDERITE® products specially formulated for specific applications including nickel-free coatings that still guarantee very firm lacquer adhesion and excellent corrosion protection on metal surfaces.

Conditioners for Zinc Phosphate

To ensure perfect adhesion for zinc phosphate conversion coatings, it is necessary to prepare the surface prior to treatment. This preparation removes oil and grease from the surface, using aqueous or solvent-based cleaning solutions, creating the ideal bonding surface for subsequent treatment.

Conditioners are used after rinses following the cleaning stage. The purpose of a conditioner is to add nucleation sites on the clean metal surface in order to promote a finer crystal structure. By increasing the concentration of the conditioner, finer zinc phosphate crystals are obtained and the overall coating weight is reduced. The conditioner stage immediately precedes the zinc phosphate stage.

Henkel supplies a range of BONDERITE® products specially formulated for preparing metallic surfaces for zinc phosphate coating thereby ensuring a tough, long-lasting, high quality surface finish.

Post Treatment and Seals

Further treatment following zinc phosphate conversion treatment has been proved to have a significant beneficial effect on the long-term performance of the coating.  Post treatment will reduce the porosity of the surface and increase its barrier performance against water and salt spray thereby improving its overall corrosion resistance long term.

Henkel supplies a range of BONDERITE® products specially formulated for the post treatment of metallic surfaces that have been undergone zinc phosphate conversion treatment designed to maximise the corrosion resistance of the surface.

Benefits of Zinc Phosphate Treatment

Zinc phosphate conversion coating is a trusted process designed to prepare metal surfaces for painting by providing an excellent foundation with the best possible paint adherence and a high level of corrosion protection.

Key features of the process include:

  • Suitable for use with a wide range of metals
  • Automatic control
  • Generates a fine crystalline coating as excellent foundation for subsequent paint coatings
  • Compatible with a wide range of solvent and water-based paints
  • Products available for use with a range of water types  

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