oxidation and cracking of copper

[Simon55]

This is sort of a two part question.
At what temperature does copper begin to experience rapid oxidation in atmospheric conditions? Is this temperature related to the type of oxide being formed? (eg CuO vs Cu203).

On a separate issue, has anyone come across branching transgranular type cracking in oxygen free pure copper - if so any idea what could cause that? I have observed this in some rotor bars from an induction motor.

 

[kenvlach]

Note: This question was answered on the Metal and Metallurgical Engineering Forum.
Additional temperature data would be welcome.

 

[metman]

Can anyone point me to the Thread that kenvlach has referenced above? Somehow I missed it on that forum.

Jesus is THE life,
Leonard

 

[kenvlach]

Here it is: oxidation and cracking of copper
thread330-38947
(Note: only required a keyword search: copper oxidation).

You may possibly be interested in
'What is the lower temperature limit for copper oxidation in ambient atmosphere?' [some good info] at

http://www.finishing.com/165/53.html

'Black copper oxide on aluminium and steel' at

http://www.finishing.com/186/05.html

'Copper Oxidization - The Thermal vs Chemical Causes' [little info, but a color photo] at

http://www.finishing.com/119/73.html