Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne CuO Conduction
Name: Glenn C.
Status: Educator
Age: 30s
Location: N/A
Country: N/A
Date: 2001

I am a safety instructor for 45 electric co-operatives in Minnesota. Recently I was asked by a power line worker, which is a better conductor- Copper or Copper Oxide. While I have been cruising around the web, I seem to find mostly that the copper oxide works best in superconductor applications. The line workers I instruct deal in kilovolts in various aluminum and copper wire conductors on a daily basis as they work at an electric utility. What is a straight forward answer I can use? Is the copper oxide better? Is that only in superconducting applications? Is the copper oxide found in corroded (when exposed to the weather) copper connections related? If so, then why does it act as resistance at typical ambient temperatures?

At temperatures your workers will encounter, copper metal is a MUCH better conductor than copper oxide. The new "high temperature" superconductors (which actually are superconducting only at temperatures far below that of dry ice) contain copper and oxygen, but they also must contain other elements, such as yttrium and barium, as well. Copper oxide alone doesn't do the trick.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois

Metal oxides are generally not very good conductors, in fact, most are dielectrics and hence non-conductors. Some metal oxides are semi-conductors (and also super conductors at low temperature in some cases). Certainly, copper and aluminum are much better conductors than their corresponding oxides at any temperature linemen will encounter.

Copper, lead, and aluminum oxides formed by corrosion are decidedly poor conductors. I am not an electrical engineer but I know if I let the terminals of a battery become corroded, the battery no longer delivers electricity (i.e. the corrosion products are insulators).

Superconductivity -- the disappearance of electrical resistance -- only operates at very low temperatures obtainable only in labs at the present time -- although there is a lot of research seeking higher temperature superconductors.

Most metals, including copper and aluminum, form thin metal oxide film layers when exposed to air for even a brief time -- this is what makes a new penny turn dull after a few days or weeks. These oxide layers are so thin however that for all practical purposes they do not interfere with the conductivity across such layers.

Vince Calder

Click here to return to the Engineering Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory