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Iron phosphate treatment of chromate treated electroplating

Does it make sense to use iron phosphate treatment on chromate treated electroplating prior to powder coating?

David Leyland
- Brooklyn, Connecticut, USA
2001

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David,

Chrome passivation of surfaces can make it difficult to get good adhesion of paint films. The typical operating conditions of an iron phosphate bath may not remove the passivation. If this is the case, then there is no benefit to treating the parts with an iron phosphate. Generally, when a paint is going to be applied, unpassivated materials are specified. Applying the powder coating to some test parts then checking the adhesion of the coating will tell if there is going to be a problem.

Roy Nuss
Trevose, Pennsylvania, USA
2001