Galvanic corrosion. What is the chemical compound of Aluminum/Stainless steel corrosion? Ph?

What is the chemical compound of Aluminum/Stainless steel corrosion? Ph? snipped-for-privacy@anadigics.com

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
dalehauck wrote:

Dale:
That depends on the chemical environment, although often it would be an aluminum oxide.
Aluminum is more active than other metals. If you couple it to stainless steel, then it will corrode (become an anode) in preference to the adjacent stainless steel (cathode) which will be prevented from corroding. The worst situation for galvanic corrosion is having a small area of aluminum connected to a large area of stainless steel.
This is briefly mentioned in the Alubook "How to avoid or minimize galvanic corrosion", Topic 11065. See: http://www.alu-info.dk/Html/alulib/modul/A00109.htm Click the arrows<< or >> to go either back or forwards in the topic.
In the UK the National Physical Lab (NPL) has a good general discussion of galvanic (bimetallic) corrosion in the Guides to Good Practice in Corrosion Control series in a big 579K file at http://www.npl.co.uk/npl/cmmt/ncs/docs/bimetallic.pdf
Also see the comprehensive lectures on aluminium, including corrosion, in the Talat series. Go to http://www.eaa.net/education/TALAT/index.htm And look first at Section 1252.
For more, also see the Talat lecture #5103, "Corrosion control of aluminium - Forms of corrosion and prevention": http://www.eaa.net/education/TALAT/lectures/5103.pdf
Also see Talat lectures #5104, "Basic approaches to prevent corrosion of aluminium" http://www.eaa.net/education/TALAT/lectures/5104.pdf
Pittsburgh Pete -------------------------------------------------------------------------------
DISCLAIMER We do not believe what we write, and neither should you. Information furnished to you is for topical (external) use only. This information may not be worth any more than either a groundhog turd, or what you paid for it (nothing). The author may not even have been either sane or sober when he wrote it down. Do not worry, be happy.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.