finishing.com logo
    HOME / sitemapFAQsBOOKSHelp WantedsAdvertiseContact   you are here: Hotline/Forum => Letter 34579
most fun in metal finishing

Gold or Silver -- 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


+++++

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). 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 and gold must be used instead.

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
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 it's resistivity is higher, then it's conductivity is lower by definition. However, whereas "better conductor" means higher conductivity, "better" conductor could be interpreted differently :-)

Maybe "better" per unit of weight, maybe more current-carrying capacity per dollar spent, etc.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
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 of 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 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.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

ADD a Q or A to THIS thread START a NEW THREADView This Week's HOT TOPICS

disclaim

 seek

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & DevicesUsed & Surplus


©1995-2014 finishing.com     -    Privacy    -    Search