Quote Originally Posted by Waterlogged View Post
There are active and passive versions of the stainless you are talking about BoxGods. The passive is most likely the variant they are using in the pumps as it's much higher in chromium. Also, here's a little food for thought, Gold is much higher on the nobility chart than the stainless we're discussing, why then did Koolance use it to cover their early copper blocks when used with aluminum rads? It's because it was so high on the nobility chart that it was actually impervious to the effects of corrosion. Once you get to a certain point on the chart, things have a natural immunity to the effects of corrosion, passive stainless isn't in that group but it's pretty close.

One more thing, I can't for the life of me remember where I saw it but, I saw something one time that showed there is some sort of voltage leak into the CPU block from the CPU, the person that found this showed that there was indeed a leak, but only when the CPU was in place. They tried testing without the CPU and the was no leak at all. IIRC, This was with C2D so I don't know if the same holds true for i7's.
I think maybe one of us is not getting the point. The 300 series stainless in the D5 would NOT be the anode...the copper in you block would be. The link I posted shows the relative voltage ranges of the various metals. Again, the LESS noble metal would act as the anode and show INCREASED corrosion while the more noble metal would be cathodic and have decreased corrosion. All of this is totally irrelevant because the 300 series stainless steel parts of the D5 are totally isolated from any other metal parts in you cooling loop ELECTRICALLY. My original point in bringing up the D5 was to demonstrate a REAL example of dissimilar metals that have been in everyone's cooling loops for years without any galvanic corrosion rather then resorting to the heard it from a guy who heard it from his brother type anecdotal evidence we normally see posted.

Here is the link again:

http://www.ceoe.udel.edu/seagrant/pu...corrosion.html

Keep in mind that that is written by a professor of applied sciences...

As for the CPU leaking an electrical charge to the block. I would doubt this but I can't say for sure. It would not matter if it HAD happened though because adding electricity to an OPEN branch still would not provide a closed contact electrical coupling. For that to happen the cpu block would need to be in contact with another dissimilar metal in the loop still...

Quote Originally Posted by Stuey View Post
For what it's worth, you don't need a complete circuit to achieve electrical contact, do you?
I am not EXACTLY sure what your asking...I am going to assume (yeah yeah I know) that you mean that for galvanic corrosion to happen you do not need a circuit because contact between the two dissimilar metals is enough...which is in its simplest terms a circuit lol.

Look at it like this.

Copper block>>>>>>>>>>tube>>>>>>>>aluminum block

That is obviously not a circuit...call it a branch and because the dissimilar metals are NOT coupled there is no galvanic corrosion happening.

Now if it went:

copper block with aluminum top>>>>>>>>tube>>>>>>>>copper radiator

you DO have the potential for galvanic corrosion because the copper and aluminum are in contact with each other AND the fluid...if you were using a non conductive fluid you would actually still be missing one of the three REQUIRED components for galvanic corrosion to happen.

See the link bellow as I think it explains it in very simple clear terms. In order for galvanic corrosion to happen you MUST MUST MUST have the following three conditions...and it lists them. At the bottom it lists how to preven them and one of them is to put something non conductive between the metal parts...like the tubing we use.

http://www.corrosionist.com/Galvanic_Corrosion.htm

I am really not making this stuff up guys...the links are from specialists and scientists, please just read it for yourselves and you will see...