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Name: Rodney
Status: other
Grade: other
Location: PA
Country: USA
Date: Winter 2013-14


Question:
I have been fascinated by the growing list of materials that are said to be stronger than steel and enjoy reading about how such materials are changing the way many products are made. The articles tend to focus primarily on the strength of such materials, but they often go on to discuss other properties. One of the properties often pointed out is the electrical conductivity, often with the materials having excellent conductive properties. I am curious to know whether any material that is as strong, or stronger than steel, happens to have very poor electrical conductivity.



Replies:
Hi Rodney,

Thanks for the question. Spider's silk and Kevlar are materials that are stronger than steel and have poor electrical conduction. For more information, I would recommend doing a patent search or a literature search of scientific and engineering journals.

I hope this helps. Thanks Jeff Grell


Hi Rodney,

In fact, most materials that are pound-for-pound stronger than steel, are not particularly good electrical conductors. Many, such as some high strength composites, are good insulators.

Materials such as carbon fiber and carbon nanotubes can have excellent electrical conductivity by themselves, but when bonded together by (insulating) resins into useful parts, their conductivity is mostly lost. Note that some sources claim that carbon nanotubes have superconducting properties, but this has not been verified, and to date, carbon nanotubes are still just a laboratory curiosity!

There are numerous high strength metals and alloys (for example, titanium and its alloys), but none has significantly better electrical conductivity than steel; in fact most are worse than steel. None (including steel) even come close to the electrical conductivity of ordinary copper.

Perhaps you have some examples of high strength materials that you feel have excellent electrical conductivity?

Regards, Bob Wilson


"Strength" can mean many different things. When you're talking about fibers, strength usually means tensile strength (pulling). The tensile strength of aramid (Kevlar) is higher than steel, and aramid is a poor electrical conductor. Another kind of strength is compressive strength (pushing). Many minerals and ceramics have higher compressive strength than steel, and they are typically nonconductive as well.

Hope this helps, Burr Zimmerman


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