Chromate based Paints versus Surface treatments

A. Hi Michael,

I don't think that you ever consider chromate conversion processes and paint primers as the same, interchangeable or even equivalent. These coatings are different on so many levels.

Often you will find conversion coatings called up as a key for paint. The typical next coating would be a chromated primer (for Defence and Aerospace anyway).

I don't think you will find specific texts that will tell you that the two processes are not equivalent, probably because the technologies are so very different.

If you want a few references then look in the books section on this site, but maybe as a start you can look at the Metal Finishing Guidebook, The Organic Finishing Guidebook, Electroplater's Engineering Handbook, Canning Handbook just to mention a few to get you going.

A. Dear Michael,

There are chromate post treatments (as chromate conversion coatings over zinc, zinc-nickel, zinc-iron, tin or other metals that can be passivated) that are complementary to electrolytic (or, in some cases, hot dip) surface treatments.

And, there are chromate based paints. Chromate based primers are paints, it is the first layer of coating you must apply, and it is the layer that gives corrosion resistance. Over the primer you apply one or more layers of different paints or topcoats.

Hope this distinction can reply your inquiry! Regards,