Corrosion of aluminum-steel interface 1

[GrizzlyRancher]

Hi,

I'm helping to design a small liquid-cooling block which will have steel inlet and outlet pipes. For thermal considerations, we are hoping to build the block itself out of aluminum. The cooling fluid will be water (likely deionized/distilled, although I am not sure at this point). The fluid will be circulated slowly through the unit at low pressure, so we will be press-fitting the tubes into the block. From standard electrode potential tables, it appears that the aluminum would be at risk of corroding. I realize that this is based on being in contact with an electrolytic solution. So my question is, since there is only water in contact with the aluminum and steel, is there a significant risk of corrosion at the interface? If so, are there any coatings (zinc?) we could use to prevent it?

Any suggestions are greatly appreciated...thanks!

 

[israelkk]

See MIL-STD-889 Dissimilar metals

 

[strider6]

Yes, there is a potential for galvanic corrosion if you couple aluminium to stainless steel and the fluid is water.
In you case the area of the aluminium should be larger than the area of stainless steel, so the galvanic corrosion effect could be reduced. One thing you could do it to use an electrical isolating spool betwenn the two materials or use an isolating kit, like picotek.

http://www.farwestcorrosion.com/ccp/flange/pikotek01-vcs.htm

Galvanic Corrosion

Bimetallic (galvanic) corrosion risks from contact with galvanised steel or aluminium

http://www.bssa.org.uk/topics.php?article=89

hope this help
S



Metal Corrosion