December 3, 2009

Flake Filled Coatings

by Bob Murphy

This is a reprint of a blog originally posted in June of 2009

A favorite quote for me comes from “Corrosion Prevention by Protective Coatings”, written by Charles Munger.¬† Protective coatings “are the skin, over the skeleton, that both protects and beautifies the bone and muscle of the world’s essential structures”.¬† That is a good analogy of how protective coatings are used for control corrosion over a variety of substrates.¬† Different formulations can increase the longevity of a coating system and the method of protection they provide.

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All coatings are barrier coatings yet they are also semi-permeable, allowing moisture and oxygen to move through a coating.¬† These two ingredients are needed in order for corrosion to take place.¬† In order to slow down this movement, paint suppliers have used many different forms of “fillers,” such as micaceous iron oxide and glass flake, to help slow down this migration.¬† These fillers provide lamellar protection.

Along with slowing down the water and oxygen migration through a coating system, fillers impart other benefits to coatings.¬† These include better abrasion resistance, better tensile strength, better flexibility, as well as the ability of the coating system to be applied at thicker films.¬† These fillers can be post-added to paint components or supplied “pre-wetted” (already in the coating).

There is generally no difference in the application of these “filled” coatings other than possibly more pressure needed for proper atomization and larger tip sizes to allow the filler to pass through the spray tip.

The cost of filled coatings is relatively small compared to the increased performance you can see with these.

Next time you are looking for long-term protection in a harsh environment, take a look at filled coatings to “fill the bill”.

This was originally posted on June 22,2009

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