question about metal mixing corrosion

copper brass and nickle, will a mixture of these cause corrosion

I hear alot of bad things about aluminum so im just gonna stay away from those

im more concerned with those three metals because i have the mcr320, ST apogee xt, ST komodo, and mcp355. Using bitspower brass barbs. Is this a conoction for trouble? what additive should i add if so

also what about silver? cani use truesilver barbs as a biocide but will it cause corrosion

Brass is an alloy of copper, and silver is not going to give you problems with galvanic corrosion. I think the nickel should be fine as well. It doesn't look like you have anything to worry about there. As long as you avoid aluminum, you shouldn't have any problems that I know of.

Actually, I've been doing some checking in that area recently ...
(Two weeks ago I would have agreed 100%)

Silver in our loops is skirting the edge of acceptability when using brass fittings. Typically, a difference of 0.15 in the anodic index of a metal is safe for virtually any environment while a difference of 0.25 is considered safe for normal environments (indoors but uncontrolled temp/humidity). I'm not sure our loops are "normal" because once the water becomes charged they're about as high humidity as you can get and provide conductivity in increasing amounts as time goes by. Whether it's sufficient to warrant raising an alarm is something that needs investigation.

Most modern plumbing fittings fall between brass and high brass for zinc content, so the difference is 0.25-0.30 - at or slightly past acceptable for "normal" conditions. That being said, most brass fitting for water cooling are nickel plated in which case they fall under "nickel", not "brass". Standard brass plumbing fittings and heater cores are problematic (which is why I was looking into it - I use heater cores).

(Metal)
(anodic index)
Silver, solid or plated; monel metal, high nickel-copper alloys
0.15
Nickel, solid or plated; titanium an s alloys; Monel
0.30
Copper, solid or plated; low brasses or bronzes (~20% Zn); silver solder; German silvery high copper-nickel alloys; nickel-chromium alloys
0.35
Brass and bronzes (~30% Zn)
0.40
High brasses and bronzes (~35% Zn)
0.45
Tin-plate; tin-lead solder
0.65
Aluminum, wrought alloys of the 2000 Series
0.75
Iron, wrought, gray or malleable, plain carbon and low alloy steels
0.85
Aluminum, wrought alloys other than 2000 Series aluminum, cast alloys of the silicon type
0.90
Aluminum, cast alloys other than silicon type, cadmium, plated and chromate
0.95
Hot-dip-zinc plate; galvanized steel
1.20




BTW - While browsing around Bitspower fittings I found some that were gold plated. Why Bitspower would do this is beyond me.
Gold, solid and plated, Gold-platinum alloy
0.00


Source: http://www.engineersedge.com/galvanic_capatability.htm

You didn't mention aluminum and why we don't use it. In the chart you provided it's 75+ up to 90. And not sure what type of aluminum like Zalman uses.

So, I'm not a science guy, but a high number more than xx vs a low recieving metal you'll have leaching of the aluminum onto the copper. I'm sure it's even worse for us watercoolers because we recirculate the water for months, allowing a lot more ions to build up to higher concentrations.

I guess the values are close enough that as long as we don't use alum which is way off the chart we'll be okay.

Conumdrum said:

You didn't mention aluminum and why we don't use it. In the chart you provided it's 75+ up to 90. And not sure what type of aluminum like Zalman uses.

So, I'm not a science guy, but a high number more than xx vs a low recieving metal you'll have leaching of the aluminum onto the copper. I'm sure it's even worse for us watercoolers because we recirculate the water for months, allowing a lot more ions to build up to higher concentrations.

I guess the values are close enough that as long as we don't use alum which is way off the chart we'll be okay.

Click to expand...

I didn't mention aluminum because we harp on it so much (as we should!) that I didn't feel it was necessary here and I wanted to concentrate on the brass/silver issue, since it's new. But looking back I think you're right, I should include Al for completeness and information (edited).


So you don't think brass & silver pose a problem even though we're pushing a little past the "normal" mark here? Maybe it won't be an issue with just a few brass fittings. Note tin, which I would think includes the tin-antimony solder used for water pipes, is even higher on the list but I've seen zero issues using that with copper (difference of 0.30) - probably because there's such a small amount in contact with the water. Same would probably apply to brass fittings and silver. I do think mixing brass fittings with gold is going into the red zone, though. Not sure why Bitspower even offers that as an option when it's not an obvious plus.


I still have my doubts about brass heater cores and silver, though. Might be prudent to separate them as much as possible but I'm not sure how much it would help (but it can't hurt!). Guess I'll know in a year or so ...