copper reaction to sulfuric acid

[zahc]

I need to make a bubbler plenum for my anodizing bucket. It would be cool to use a coil of copper tubing with tiny holes in it, but will copper be attacked by the acid? it's battery acid diluted 1 part battery acid and 2 parts water. It's probably possible to tell by considering the reduction potential of copper if you are smart with chemistry.

[K Frame]

The way I read it it, no, that's a dilute enough solution that the acid won't attack the copper.

[dogmush]

This paper: https://www.nickelinstitute.org/media/4122/alloy-selection-for-service-in-sulphuric-acid-10057.pdf says no.

On Page 9:

Copper and its alloys
With rare exceptions in which the acid is kept in a reducing condition, copper-based alloys cannot be used in weak sulphuric acid. The corrosion is autocatalytic, the accretion of dissolved copper providing increasing levels of cupric ions which are themselves oxidising contaminants.

That's from the section on intermediate and dilute acids. (5%-25% H₂SO₄ )  Your solution should be around 12% (Battery acid is 37%, mixed 1:2 with water should be 12ish)

It looks like 304 Stainless would be a decent choice, and it's pretty available in tube form for not too much money.  That might be my choice.