The waterblock being covered with carbon seems odd to me. Atmospheric CO2 breaking down due to high temperatures but then the carbon doesn't burn off again as the piece cools? Perhaps the black material is some component of the copper alloy that oxidized? I'd be concerned that the mass of the material, or composition of the alloy might have changed enough to skew results. It would be better to allow the test piece to cool in the Argon to prevent this.
Also, heating the copper to the point that it flows could skew results due to changes in resistance resulting from thinning or thickening the copper in spots.
I could probably measure the resistance of a White Water baseplate to about 1% accuracy, but most waterblocks would be too thick for me to get a useful measurement.
It's much easier to measure the resistance of a reasonably thin, long wire, but it would be easy enough (for me) to measure the resistance of something like a 4" X 0.5" X 0.05" strip with 0.25" long slots cut into each end of the strip. (The slots in the ends are to provide 4 connection points. Two for connecting a current source and two for connecting a voltmeter.)
If you want to send me a strip like this, of the alloy you are using, I will measure the resistance of it, and send it back. You can anneal it and send it back to me, and I'll measure the resistance again.
Alternatively, I can send you a strip of copper and you can anneal it and send it back, but what I have available is some ultra pure oxygen free copper that won't necessarily reflect the behavior of your alloy. Also, the stuff I have is already annealed, so I will have to bend it, pound it with a hammer, whatever, to get it hardened. (I don't know exactly what the stuff I can get is. It was imported from Japan for some hare-brained scheme by a former coworker.)
|