Conflicting problem...galvanic corrosion and floating metal!
Conflicting problem...galvanic corrosion and floating metal!
(OP)
I am running into a conflicting problem. I am trying to bolt down a small aluminum casing on a large nickel plate....due to the fact that we need to ground this aluminum casing to the Ni plate. In order to accomplish that, I need to rid of the anodized surface of the Al.... now I got a new potential problem--galvanic corrosion. How can I resolve this? If I prime the Al surface with some sort of conductive primer such as the black BR127 esd or a conductive paint of some sort, will this help with the galvanic corrosion issue? Or anyone has any other ideas?
Much thanks in advance for your help!
Much thanks in advance for your help!





RE: Conflicting problem...galvanic corrosion and floating metal!
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Conflicting problem...galvanic corrosion and floating metal!
Right now the Mechanical folks decided instead of getting rid of hard anodized on the bottom of AL in contact with Ni, they decided to rid of the top layer. bolt it down with a CRES washer in contact on the top surface. Now I am more worry about the huge EMF difference between CRES and bare Al. Thus a new question arise...what is a good surface ratio of cathode(CRES) vs anode(Anode) where you are comfortable to say that your risk of anode corrosion is going to be small?
Thanks!
RE: Conflicting problem...galvanic corrosion and floating metal!
RE: Conflicting problem...galvanic corrosion and floating metal!
Thanks in advance for anyone's input!
RE: Conflicting problem...galvanic corrosion and floating metal!
If the ref. I am looking at is correct then you have a potential difference of over ~0.8 [V SHE] between Ni and Al.
Also, is it possible to insulate the Al casing from the Ni plate with a non-conductive coating or plate ? and use ceramic washers and / or bolts. Its not an ever lasting solution since over time you will still get galvanic coupling but as a last resort it could help.
libriut99