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Powder coating on top of MAO coating [India] 

November 21, 2007

I am an MAO technology researcher. I heard powder coating is being carried out on the top of MAO coating (on Al) probably to reduce friction and to impart smooth surface finish and/or to reduce the ill effects of surface defects. Is any one had an idea of what powder coating is done, how it is applied and what is the basic requirement of such a coating?

Rama Krishna Lingamaneni
Plating technology researcher - Hyderabad, Andhra Pradesh, INDIA

What I love about this forum is that some of the questions make you wonder, "What is this guy talking about". This time, it really did make me question what an MAO coating is. After a Google search, you find out that MAO equates to "Micro-arc Oxidation". For further information on this subject, see letter #685. I found Ted's remarks after the first few entries quite humorous as the contributor's letters became more commercial than informative.
Anyway, back to the question of who is PC MAO coatings, how are they applying the powder and powder characteristics? One would expect that it would be an architectural quality polyester powder, applied using either tribo or corona PC equipment. My thoughts are why MAO in the first place because an approved applicator can obtain a 25 year guarantee from the powder manufacturer for all the PC aluminium extrusions that are processed.
Just read my reply, I have just committed the same sin – PC is short for Powder Coating.

Terry Hickling Martex Paints Ltd    Birmingham, UK