20% H2O2 Wash Down on 6000 Series Extrusion

[MadMango]

I'm reposting this question here from forum404.

I have never dealt with a 20% hydrogen peroxide wash down environment before. I know hydrogen peroxide is acidic. Working with 6000 series aluminum extrusions, what would be a recommended finish for the extrusions? I need to clarify with the customer, there specs mention "occasional wash down", and I'm not sure if that is weekly, monthly, or other.

These extrusions will be attached to painted steel racks, do I need to isolate them to prevent further corrosion? The contact area will probably be very small, perhaps 8sq inches over a length of 9ft.

Some replies suggested a clear powdercoat over clear anodize, a nickel/teflon infused matrix coatings, and a recommendation that I contact General Magnaplate to see what they have to say.

To add to the above, these extrusions are being used in an agricultural application, being part of LED growth fixtures for an indoor "tobacco farm."

Thanks in advance.

"Art without engineering is dreaming; Engineering without art is calculating."

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[TVP]

In general, hydrogen peroxide is not corrosive to aluminum. Here is datasheet from Solvay describing suitable materials for storing hydrogen peroxide:

http://www.solvaychemicals.us/static/wma/pdf/6/6/0/9/HH-958.pdf

If the aluminum extrusions are going to be directly connected to painted steel, then you may not need any additional coatings. However, if you do need some type of coating for corrosion resistance, etc., then the recommendation for a powder coating is a good one, since they tend to be thick and offer good isolation. There are multiple pretreatments that can be used with this, including anodic coatings, phosphates, and newer chrome-free coatings. Keep in mind that many powder coatings require curing at temperatures above the T6 tempering temperature for 6XXX series alloys like 6061, so you need to specify a low cure temp version if you want to avoid softening of heat-treated extrusions.

 

[strider6]

I've found this interesting article on material selection for hydrogen peroxide handling:

http://www.gkllc.com/home/AIAA-2005-4551_Long_Term_Storability_of_Hydrogen_Peroxide.pdf

there are data also for aluminum alloy 6000.

hope this help

S

Corrosion & Rust Prevention Control

 

[MadMango]

Thank you both for the informative PDF links. Seems the customer has dropped this requirement, though I'm not sure if that was a good thing or bad. I'll keep this info in my back pocket.

"Art without engineering is dreaming; Engineering without art is calculating."

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