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Gold, Silver, Copper, Aluminum -- which is the better electrical conductor?


Q. I once read that Silver is a better conductor of electricity than Gold, the problem with silver however is that it is very rigid and tarnishes very easily. Am I correct?

Wellsley Over
- Johannesburg, Gauteng, South Africa


Electricity and Electronics

A. Yes you are correct.

Good luck!

Goran Budija
- Zagreb, Croatia


A. Also better than gold is copper. Metals are nature's better conductors. Of course modern physics has invented (or should I say discovered?) superconductors. Zero resistance and they're not even metals.

Guillermo Marrufo
Monterrey, NL, Mexico


Q. So, silver is a better conductor than gold but because it's not smooth and builds up a tarnish, the gold is better in the long run? Well the original question is if silver is a better conductor why do they use gold on cars' electrical components?

Justin Hansen
ase certification - Ogden, Utah, USA


A. You have to look at two different things, Justin: the resistance of the solid material that is the conductor, and the resistance of the joint (or connection / contact surface / interface, or whatever you want to call it) that the current also has to pass through. Silver has higher conductivity (lower resistance) than gold. But it tarnishes, which means a high resistance oxide/sulphide forms on its surface. Silver is fine for many things, but where a very low voltage and low current is involved (for example in some electronics signals) the tarnish can interfere with the signal at the joint, and gold must be used instead.

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

July 23, 2008

A. Silver is the best conductor, but usually not used due to expense. It would not surprise me to see it used in integrated circuits someday, however, like copper is now (and aluminum is/was). The difference isn't a lot, but 5% is 5%.
Tarnish could be a problem for high frequencies where skin effect becomes critical.

As for superconductors, most of the commonly used ones are in fact metals. A common one is an alloy of niobium and tin. The metallic ones are used for two reasons. First, wires can be easily made and coils easily wound. This on its face wouldn't be a deal breaker. You can easily imagine depositing films of superconducting material on drum,etching it,adding a insulating layer and repeating,thus creating a large number of windings.

The real problem is that the high temperature superconductors lose that property in high magnetic fields, which happens when you use them with high currents. The low temperature superconductors do this too, but at much higher currents so they are more useful. (Super conductors are mostly used for very high power magnets).

Tarnish on silver could become critical for applications where skin effect was important (high frequencies). In fact, in high powered RF amplifiers coils are often made from copper tubing and gold plated. Although gold is not as conductive as copper, it is resistant to corrosion. If the layer is thin compared to the thickness of the layer the current flows in, most of the current will flow in the copper anyway.

If skin effect was the only issue with silver, then we could find ways to deal with that. The easiest way to deal with it would be to deposit a thin layer of a inert material (alumina?) on the surface to prevent corrosion. If it was thin and robust enough,it could prevent corrosion while still transferring enough heat and not increase the size of the wire. The final answer comes down to cost. A silver wire would cost over 100 times a copper wire. While it might be useful in a semiconductor chip, where the actual cost of the silver would be very small compared to the cost of the chip, in a speaker cable it would be prohibitive (in a satellite, spacecraft, or weapon system, it might be ok, if the benefits justified it.)

Michael Michalski
- Kent Ohio

July 22, 2010

Q. Why is aluminium a better conductor when its resistivity is higher than gold?

Gary Low
- Subang Jaya, Selangor, Malaysia

July 22, 2010

A. Hi, Gary. If aluminum's resistivity is higher, then by definition it's conductivity is lower; so aluminum is NOT a "better conductor" than gold.

However, whereas "better conductor" means higher conductivity, " 'better' conductor" might be interpreted differently :-)

Aluminum is probably a "better" conductor than gold if by "better" we mean "per unit of weight", or "per dollar spent", or things like that :-)


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

January 31, 2012

A. Don't know if what I do is legitimate methodology, but when I am building Antennas, particularly high frequency stuff, I make the elements, waveguide, feedhorns, etc., out of copper, then electroplate them with silver, and then a thin layer of gold on top to prevent the tarnishing of the silver. I don't have the time or equipment to do precise measurement to see exactly what effect this has on the overall efficiency. I just figured that structurally the copper is good and easy to work with and cheap compared to the silver or gold. I figured that the silver plating would provide excellent characteristics considering the skin effect of UHF. Then to get away from the tarnish issue decreasing the conductivity of the silver, I plate a very thin layer of gold on top of the silver. I may be wrong but I felt that this should give one pretty close to the cost of the copper, with the conductive characteristics of silver and the non tarnishing characteristics of the gold. Maybe someone can tell me if the gold plate on top of the silver eliminates the conductivity of the silver? If so then the silver plate is a waste and one would be better off just plating a thin layer of gold on the copper. From what I can see it seems to work quite well, but then I reckon the gold would.

leonard legg
Leonard Legg
- Durango, Colorado, U.S.A.

November 20, 2012

A. I want to share my experiences.

YS Subramanyam
retired aviation specialist - Nellore, Andhra Pradesh, India

This site is primarily about metal finishing rather than aviation, but yes, please do share your experiences.

December 3, 2012

Q. Why does Gold not have a greater electrical conductivity than Silver? There is an s valence electron in both their valence shells. [And half filled s valence shell has fermi energy within its maximum energy state, which I think is the reason for their high electrical conductivity]. The reason I have this question is that, since the valence electron of gold must experience a lesser effective nuclear charge than that of silver [Because a Gold atom is bigger than Silver], it must be easier to excite right? Just curious.

Ranjit Raj
- Chennai, India

January 19, 2013

A. Silver is a purer metal than gold, it is a better conductor than gold but honestly I think it has a lot to do with time (money in the long run) and because society (humans) have invested so much into gold throughout the generations that you will never get the truth regarding which is better because we will never be told the truth and the fact that we have relied on gold as a currency (gold is just a better decoration than silver, it always has been, read the bible even God likes toys of gold). I think we have just stockpiled so much over the generations that we have to do something with it, just think about it: the ancient Egyptians stashed it because it was pretty and their pharoh liked it (it looked better on his slave girl than silver), but look at gold's weight, its high temperature to melt down is higher than other metals, it doesn't mix well with other metals nor chemicals, and to actually make gold a better decoration is to mix it with copper). The whole debate is currency and that is it.

And also take this simple little statement from a sales perspective: wants have always paid better than needs

Gabriel C Shrader
- Virgin Islands

June 26, 2014

Q. Hi there. I am sagar; my question is which is the best conductor gold or silver? If your answer is silver, how because the gold having corrosion resistivity know that's why, please clarify that to me.

Sagar R Malur
- malur, karnataka, India

June 2014

A. Hi Sagar. Silver is definitely the best conductor. If you had a wire of a given length and diameter made of silver and a wire made of gold with the same dimensions, you would find that the resistance of the silver wire is less.

But if you now painted the ends of the silver wire, such that you had a resistive layer of paint interfering with the ability to get electricity through the paint layer and into & out of the actual silver, you would report that there is a problem using painted silver wire for certain applications.

When silver is exposed to the atmosphere, the topmost layer reacts with the air to build a tarnish layer of silver oxide or silver sulphide which is not conductive. This tarnish acts like the paint -- it makes it difficult to get electricity into and out of the actual silver. It's not terribly important for high voltages and high currents which can just power their way through the tarnish, but for electronic circuits of very low voltage and very low current, the silver tarnish can be an effective insulator.


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

sidebar2 December 1, 2014

Q. What is the advantage of double bus bar system that indicates additional cost compared to single busbar system?

sovit raut
- kathmandu,Nepal

January 2015

A. Hi Sovit. Hopefully someone else has a clear picture from your question, but I don't :-(

I can't help you unless you expand upon your question and put it in context by describing your situation. Thanks.


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

Using copper-gold alloy for alternator wiring

January 9, 2015

Q. We all know that silver and gold are very good conductors of electricity. My question is: if we are using an alloy of gold and copper in Alternator coils, what effects are determined as compared to copper winding coils?

Vishant TG
engineering - meerut,utter pradesh,india

January 2015

A. Hi Vishant. I don't have the electrical engineering background in alternator design to answer your question. But I doubt that an alloy of copper and gold will be a very good conductor. My limited understanding is that copper and other metals must be of very high purity for good conductivity. I can't quickly locate a chart with the electrical conductivity of karat golds, but I do see at
that the conductivity of several copper alloys is the range of about 4% to 15% of pure copper.


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

Speaker cable copper oxidation or tarnish

February 28, 2015

Q. I have some PVC (Clear) insulated, stranded bare copper speaker wire. In some of the strand interstices there is visible black or green tarnish or oxidation. This is not just adjacent to cut ends, but far up the cable. These wires are just 4 years old.

What likely caused this?
Is this a manufacturing defect?
Should it be happening so soon (if at all)?
Is this detrimental to the performance of the wire?
Is this something that I should ask for my money back on?

Thank you for your help

Dave Philip
homeowner - St. Charles, IL USA

February 2015

A. Hi Dave. Although you consider cable that is four years old to be relatively new, most people and most manufacturers wouldn't. You could try sending photos to the manufacturer and see if they will do anything out of good will, but I don't think they will.

It is very hard to say what is causing the corrosion. There was a Chinese wall board scandal a few years ago where the plaster was so full of sulphides that it caused all the nearby copper pipe and wiring to turn green and black. Moisture wicking up from the uninsulated ends can cause the same thing. A very cold air conditioning duct nearby could cause some condensation on the cable ends and be drawn up under the insulation by capillary action. Unless the corrosion is in the middle of the wire in a spot which simply can't be reached by environmental factors it would very difficult to assert that it was a manufacturing defect.

Surface tarnish probably doesn't radically affect the current carrying capacity of the wire, and it's usefulness for driving large speakers; but it depends how bad because if it's serious corrosion to where a lot of the copper is gone, then a lot of the current carrying capacity is gone too.


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

October 8, 2015

Q. Is there a specific compound/allloy/allotrope that would work better than silver, gold and copper? I have searched the web for 30 minutes and can't get anything. I am doing a 6th grade SS project and would like an answer ASAP. Maybe you can help?

T. Trollington
I'm a kid - Wylie, Texas, U.S.A., North America, Earth, the Solar System.

October 2015

A. Hi T. Pure copper may be your best bet because it is far cheaper and far more available that silver or gold, whereas silver is only about 5% more conductive than copper, and gold is less conductive than copper. You could google "relative conductivity chart". Pure copper wire is available from every hardware store.

Generally, alloys are not good conductors compared to purer metals -- probably related to the way free electrons can easily "bounce" from one copper atom to the next, but the path is not as smooth and easy if an atom of a different metal is encountered.

But, to avoid demerits, be very careful about using phrases like "would work better" unless you can enunciate rather precisely what that phrase means to you.


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

November 2, 2015

Q. My question is, since gold has got high ductility property, why can't we use gold and Copper alloy as a cable wire?

kiran h kalmani
- karnataka , India

A. Hi Kiran. Who said you couldn't?

But alloys generally conduct electricity more poorly than pure metals. And what specific alloy of copper and gold are you thinking of which displays high ductility? And what exactly do you mean by "cable wire" -- because gold would be impossibly expensive for the cable wires I picture.

Abstract questions bring with them a dozen "ifs, ands & buts" that require a book to answer -- the relatively short length of forum responses mean that only very specific questions can be answered. Please get back to us with the full details of your situation. Thanks!


Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

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