Copper Wire Embrittlement
Copper Wire Embrittlement
(OP)
I was wondering if anyone had experienced copper wire embrittlement. Working on a generator, I noticed that some of the wires (near a connection point) were stiff. In addition to this, the silver coated stranded copper wire had darkened (indicating silver oxide formation).
I believe that this had caused a high-resistance connection. Data collected indicates that temperatures approached 300°F. I think that this covers all the symptoms that I know of, but if you need any additional information/clarification, I will do my best to oblige.
Does anyone have any insight on how this happened and/or the metallurgy involved? Any and all insight is appreciated.
I believe that this had caused a high-resistance connection. Data collected indicates that temperatures approached 300°F. I think that this covers all the symptoms that I know of, but if you need any additional information/clarification, I will do my best to oblige.
Does anyone have any insight on how this happened and/or the metallurgy involved? Any and all insight is appreciated.






RE: Copper Wire Embrittlement
RE: Copper Wire Embrittlement
And no, no rotten eggs around. Could sulphur in diesel fuel (exhaust) cause this?
RE: Copper Wire Embrittlement
Okay so if you're not in some chemical plant or worse an oil field then HS probably isn't it.
However the rule mentioned above still applies. So if you have copper wires normally running around 300F then oxidation and chemical reactions between dissimular metals will speed (way) up. This is simular to your incandescent lamp holders puking-out after ten years and when you take them apart the copper wire is black and the screws are 'changed'.
Copper is embrittled by Hydrogen, Oxygen, Bismuth, Antimony and Mercury. Also apparently copper will become brittle due to inclusion of Sulfur molecules thru temperature cycling. You could find Sulphur in your diesel.
RE: Copper Wire Embrittlement
Since work hardening changes the crystal structure, it would be possible to get a resistance change.
TTFN
RE: Copper Wire Embrittlement
RE: Copper Wire Embrittlement
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RE: Copper Wire Embrittlement
"It is worthwhile to point out that the copper wire industry did not start making OFC wire for the needs of the audio industry! It was first made because the windings of large electrical generators, made from standard copper, would became brittle and fail due to their continuous exposure to high temperature, high g-forces and vibration. Generator windings made from OFC copper last longer. Apparently it is now routine for much, if not all, copper wire to be made under OFC conditions. Because of this, the difference in cost between ETP and OFC copper wire is small." http:/
RE: Copper Wire Embrittlement
IR - I don't believe it is work hardening as the wires are strain relieved fairly well. In addition, it only happened on some of the wires... likely the ones that got hottest.
Looks like I have some research to do with copper and silver reacting with sulphur. Thanks for the info!