While most homes and electrical applications are wired with copper, is copper really the best natural conductor of electricity? Other than copper, aluminum can also be found in electrical systems, especially in older applications. So what is the best natural conductor?
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Among all of the natural metals, there are four that are primarily recognized for their electrical conductivity. These include copper, aluminum, silver and gold.
Copper is an orange-colored metal that can often resemble bronze. Aluminum is a bright white metal that. when exposed to air, becomes oxidized and can develop a cloudy, dust-like film. Gold is a bright yellow metal that is not used in residential or commercial wiring applications. Silver is a bright white metal that is highly resistant to corrosion. It is also not found in wiring systems.
Many people believe that since copper is used in modern residential and commercial wiring applications that it is the best natural conductor. This is not true. The same applies to aluminum. Gold is used in high-end electronic connectors, which are gold-plated. But the truth is, gold is preferred for these applications not because it is a great conductor, but rather because it is highly resistant to corrosion. For the absolute best conductivity, silver is tops.
Silver has delocalized electrons that can move around freely. Since they are free to move, they are able to keep their metallic bonds intact and electricity can flow more cleanly through the metal, with very little resistance from other atoms.
While silver is the best natural conductor, it, like aluminum, will oxidize in an oxygen-rich environment. For this reason, silver is used quite often in specialized equipment built by NASA where it can deliver exceptional conductivity with no threat of oxidizing. Silver can be found within the circuitry of many satellites.
Even though silver is the best conductor of electricity, copper is a very close second. This, plus the fact that copper is relatively inexpensive and easy to work with, make it the conductor of choice here on Earth.