Would it be ok to fill the copper heatpipes with mercury on my cpu cooler since its the best metal conductor?

Question

and do vacuums transfer heat well. and what if there was a cpu coated in really coarse diamond dust. anyone feel free to add in your own ideas of cpu coolers.

Answer 1

A few misconceptions here. Mercury is not the best heat *conductor*, but can be used to cool more effectively than a passive solid heat sink because it expands when heated and, being fluid, rises due to buoyancy and *convects* the heat away. You need a vertically looped tube of copper, then, (well sealed for safety) where it rises on the hot end and falls on the cold.

Of course, CPU coolers are not "passive solid heat sinks", but are actively cooled by a fan. That's the standard solution. However, fans have moving parts that make noise and wear out. If you want to make a "heat pipe" (that's what it's called) system, avoiding those issues are the advantages. So, go for it.

Vacuum does not transfer heat well at all because it neither conducts nor convects. It can only transfer heat by IR radiation (very inefficient).

Scott just said copper dissolves in mercury. If so, maybe stainless steel will work. It's not a very great heat conductor, though.

Answer 2

Interestingly you can already get chips that are cooled by a liquid metals. Well alloys (normally gallium based). See the first source for a funky picture of these. The magnetic drive mechanism is quite interesting.

Secondly with the rapidly decreasing price of diamond coating (eg you can now get disposable diamond coated razors). Plus the growing ability to do thicker coats means diamond cooling will arrive very soon. It's already available to researchers in various fields as the second source shows. I myself have a high voltage diamond support.

So a liquid metal cooled solid diamond heat sink may not be quite available yet. But I bet it is within 10 years.

O by the way it has to be solid diamond not dust. In dust the phonons (the things that transfer heat so well in diamond) can not cross between dust particles so heat transfer is not good. This is why diamond dust does not feel cold like a solid lump of diamond does.  

Answer 3

Copper dissolves in mercury, so you would end up with a real mess!

Answer 4

Mercury is too dangerous to work with. Will you remember to dispose of it correctly years from now when you toss the PC?  Or if you sell it, will the new owner know to do that?

Vacuum is a very good insulator. Remember thermos bottles, which are only two containers separated by a vacuum?

edit: I don't know if water pipes take advantage of the huge amount of heat taken to boil water, but if they do, that might make them better than using Hg.

Diamond dust is not good, it is too irregular. A solid block of copper would be better, with a good thermal connection to the device.

Thermal conductivity table (W/m K):

Silver429

Copper401

Gold310

Aluminum250

diamond 2000–2500

Answer 5

Mercury is far too hazardous to your health to be used like this.  I would not recommend it.

Answer 6

Nope, Heat pipes Work By Convection.