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A North Carolina State University researcher has developed an efficient and inexpensive way of cooling electronic devices that generate a lot of heat, such as lasers and power devices. The technique uses a heat-sink made of a copper-graphene composite, which is attached to the electronic device using an indium-graphene interface film. Apparently, copper-graphene composite cools down things 25% faster than pure copper.

“Both the copper-graphene and indium-graphene have higher thermal conductivity, allowing the device to cool efficiently. The copper-graphene composite is also low-cost and easy to produce. Copper is expensive, so replacing some of the copper with graphene actually lowers the overall cost,” said Dr. Jag Kasichainula, an associate professor of materials science and engineering at NC State and author of a paper on the research.

The paper also lays out the manufacturing process for creating the copper-graphene composite, using an electrochemical deposition process.

Samples of graphene composites with matrix of copper were prepared by electrochemical codeposition from CuSO4 solution with graphene oxide suspension. The thermal conductivity of the composite samples with different thickness and that of electrodeposited copper was determined by the three-omega method. Copper-graphene composite films with thickness greater than 200 [micron] showed an improvement in thermal conductivity over that of electrolytic copper from 380W/m.K to 460W/m.K at 300K (27°C). The thermal conductivity of copper-graphene films decreased from 510W/m.K at 250K (–23°C) to 440 W/m.K at 350 K (77°C).

Effective medium approximation (EMA) was used to model the thermal conductivity of the composite samples and determine the interfacial thermal conductance between copper and graphene. The values of interface thermal conductance greater than 1.2 GW/m2.K obtained from the acoustic and the diffuse mismatch models and from the EMA modeling of the experimental results indicate that the interface thermal resistance is not a limiting factor to improve the thermal conductivity of the copper-graphene composites.

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Comments currently: 4
Discussion started: 04/12/12 06:32:15 AM
Latest comment: 04/13/12 03:44:21 PM
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Looks promising though the operating range seems some what limited for some applications with thermal conductivity dropping off at 77C.
0 0 [Posted by: beenthere  | Date: 04/12/12 06:32:15 AM]
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It's a relative comparison to thermal conductivity of the electrolytic copper. The fact that the Cu-graphene composite achieves pretty much same or better thermal conductivity levels at 77°C as electrolytic copper does on average at only around 27°C is a great deal, especially when it also introduces cost savings to the mix On a side note, those pictures attached are of Zalman CNPS8900 "Extreme Pure Copper" 110MM Fan CPU Cooler... I imagine the composite would absorb light a bit more than that.
1 0 [Posted by: MyK  | Date: 04/12/12 09:07:20 AM]
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2. 
We'll see if reality matches theory. That's always the challenge.

With Intel CPUs running at temps. above 77C, this material may still have limited application with non-linear thermal conduction dropping off at only 77C.
0 0 [Posted by: beenthere  | Date: 04/12/12 09:17:48 AM]
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I'd go out on a limb and speculate that adding graphene "to the mix" (no pun intended) reduces the drop in thermal conductivity performance, mostly due to it stretching a whole lot less under higher temperatures and thus retaining its thermal characteristics better than copper itself. Meaning, the higher the temperature the better it performs relative to pure copper designs. Still, this research is primarily important for OEMs and not as much for custom aftermarket coolers like the one on the photo above where it's more in the design itself and quality of manufacturing processes than the materials chosen. Especially when we're talking of only 10% better real-life performances at best (at temps till say 90°C). I can see this research finding ways into fanless power supplies in a few years time though, especially since they mostly use really simple heat dissipation plates that are easy to manufacture using various materials Adjusting a manufacturing line to produce complex designed aftermarket coolers and heatsinks using uncommon materials is a whole different ball game though and would introduce more costs to it than the material itself might save.
1 0 [Posted by: MyK  | Date: 04/12/12 10:17:30 AM]
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