Why use only Copper or Aluminum

Red Falcon

Red Falcon

[H]ard DCOTM December 2023
Joined
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Why is it that only copper and/or aluminum elements are used?

Is it not possible to have brass, steel, iron, nickel, silver, gold, or lead heatsyncs?

Obviously silver and gold would be expensive and lead would not be ROHS compliant, but if a person could, why or why not?

I would appreciate all info on this immensely. All thanks in advance!
 
Heat capacity... Copper is the second best "common metal" in terms of heat capacity and dissipation... It's beaten only by silver (and carbon nanotube, beryllium, sodium and diamond, etc.). Something like gold, or lead, with a low specific heat capacity won't wick heat away from the hot component, nor release it fast enough, to be an effective sink.

Aluminum is used because of it's weight and ease of machining.
 
I always thought copper was second to gold. Interesting on the silver.

I wonder what happened to that silver heatsink that guy was making a while back here.
 
colinstu said:
I always thought copper was second to gold. Interesting on the silver.

I wonder what happened to that silver heatsink that guy was making a while back here.
Click to expand...

oh he is working on that project alright, hope to hear news from him soon :)
 
I just learned about this a few weeks ago in chem class. :)

You could make a silver core surrounded by copper, similar to how Intel stock coolers have a copper base surrounded by aluminum. I'm just not sure the benefits outweigh the cost.
 
I want Titanium or Tungsten Carbide cooling components... even if my hardware dies, it will look cool doing so!

Oh, and I really want to see a Carbon Fiber case: Please link if there is one available!
 
bholstege said:
I just learned about this a few weeks ago in chem class. :)

You could make a silver core surrounded by copper, similar to how Intel stock coolers have a copper base surrounded by aluminum. I'm just not sure the benefits outweigh the cost.
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The thermal capacity of silver is less than 5% better than copper, so... No.

The best would be a magnesium core, lapped perfectly flat, surrounded by copper fins. Magnesium is too brittle to use alone though.
 
You can stick any lump of metal on your CPU in theory, but it comes down to both economics and physical characteristics, yes.

This may help for thermal conductivities, although most of the data is only at 25C:
http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

We see, therefore, that making your heatsink out of cotton would be a very bad idea. At the other end of the scale, silver is best, but only by a little. Then copper. Gold is significantly worse than copper, and aluminium a little worse again. Then it's beryllium, and it starts dropping quickly through magnesium, iridium, molybdenum, zinc, brass, cadmium, nickel, sodium, iron, platinum, cobalt, tin, steel and lead. Carbon is way down.

At 25C:
Magnesium: 156 W/mK
Beryllium: 218
Aluminum: 250
Gold: 310
Copper: 401
Silver: 429

Based on that, a heatsink made entirely out of silver would be best, but also rather on the expensive side. Copper is both very conductive and also more feasibly-priced, making it a good option, but it's still expensive; aluminium is decently conductive and also a lot cheaper, so aluminium/copper combinations are popular. A gold heatsink would be a waste since it would be better and cheaper made of copper. No other metal is worth considering.
 
Mithent said:
Carbon is way down.
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If you were implying that carbon == carbon nanotubes, it's not quite the case.

There's some debate on values, but most figures I've seen put carbon nanotubes @ > 3000 W/mK.

Although it's obviously infeasible to make a heat sink out of them .. seen figures like $7000/gram
 
nickel is used on waterblocks now.

Thermal conductivity, heat dissipation, and cost of materials all play a part in it.
 
tgrimley said:
If you were implying that carbon == carbon nanotubes, it's not quite the case.
Click to expand...

Ah, no, carbon nanotubes have different properties; this would presumably be putting a large block of carbon on your CPU.
 
Yea actually carbon has several types.Diamond has a conductivity above a thousand .Synthetic diamond is actually used for thermal management for large output fiberoptic drivers.....also , graphite , in the direction paralell to the planes of it's crystal , is a very good conductor of heat ,exceeding that of silver as well....

:D
 
hmmmm how about a heatsink made entirely out of a semi-stable blob of arctic silver 5? perhaps in the shape of ghostbuster's stay-puff marshmellow man?
 
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