# Exotic heat sink materials?



## AaronM (Nov 29, 2008)

Tellurium Copper: What good is it? From what I can find on the web, it's just easy to machine...is that it?

Any other Krazy materials out there?


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## TigerhawkT3 (Nov 29, 2008)

Diamond! Won't scratch, break, or spark, and has ten times the thermal conductivity of aluminum. Mmm, tasty.


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## AaronM (Nov 29, 2008)

Well, that certainly is exotic...too much so.
I'd never be able to work with that or afford it.


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## csshih (Nov 29, 2008)

you can buy diamond heatsink paste out there.
http://innovationcooling.com/

it's decently cheap for diamond.


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## snarfer (Nov 29, 2008)

I got samples of carbon fiber and graphite heatsink materials from several manufacturers, only to discover that they aren't nearly as good thermal conductors as they're cracked up to be. Those massive thermal conductivity numbers (two or three times the conductivity of copper along the fibers) really only come into play at temperatures far above what you could run an LED at. 

I saw another exotic solution with some promise in a patent filing from a Taiwanese company. They sintered vacuum grown carbon fibers into a copper matrix. Supposedly the resulting material had excellent strength, machinability, and thermal conductivity in all directions.


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## modamag (Nov 29, 2008)

Tellurium Copper is easy to machine. BUT! IT'S VERY DANGEROUS!

In my infancy I made couple PXR2 out of it.

What I would do for an affordable solution is to use diamond paste and aluminum backing. That way it'll get the heat away from the source quicker and not retain it (eg. copper)


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## AaronM (Nov 29, 2008)

How do you mean dangerous?
Will it explode? kill your firstborn if you don't heed astrological signs?


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## PCC (Nov 30, 2008)

I did a Google search for "Tellurium copper dangerous" and found this:

http://www.espi-metals.com/msds's/Tellurium%20Copper.htm



> *IV FIRE AND EXPLOSION HAZARDS DATA*
> 
> 
> *Flash Point*: N/A *Autoignition Temperature*: N/A
> ...


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## qwertyydude (Dec 1, 2008)

It's not the tellurium copper that's dangerous, it's the fact that it's a metal dust. Toxicity you're thinking beryllium copper, now that's a real carcinogenic hazard. Metal powders themselves are dangerous, even thermite is only aluminum powder and rust dust.


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## starburst (Dec 1, 2008)

I alway's wanted to try silver, I got some .999 % around here somewhere.


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## hank (Dec 6, 2008)

Here are some heat sinks meant for fixed lighting:

http://lsgc.com/products/peripherals/thermacool-heat-sinks/

That page links to: 

http://www.laminalighting.com/ProductsandSolutions/ProductsandSolutions/Accessories/HeatSinks.aspx

Gotta say, they could create an interesting looking flashlight if the fins aren't too fragile, or with a collar or something to protect the fins but leave airflow open from the sides.


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## yellow (Dec 8, 2008)

is there anything that has better thermal capacities and - at the same time - less weight than Aluminium?

(additional _less cost _is not possible, eh?)


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## qwertyydude (Dec 8, 2008)

If you design it right a heatpipe system can be more efficient at removing heat from a small area and distributing it to a larger area. It may not necessarily be lighter than an equivalently sized block of aluminum but if designed properly it'll be lighter than a traditional heatsink of equivalent cooling value.


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## sector_cleared (Dec 8, 2008)

On the Lighting&Building Fair in Frankfurt some months ago I saw this heatsink material:

http://www.ceramtec.com/index/produ...gh_power_led_systems/01114,0123,0453,0741.php

http://www.ceramtec.com/index/products/ceramcool_ceramic_heatsink/materials/01122,0123,0453,0746.php

Looks pretty cool to have a white heatsink :twothumbs 
The thermal resistance approx. the same as the one of AL6061 but the density is slightly higher.


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## VegasF6 (Dec 8, 2008)

snarfer said:


> I got samples of carbon fiber and graphite heatsink materials from several manufacturers, only to discover that they aren't nearly as good thermal conductors as they're cracked up to be. Those massive thermal conductivity numbers (two or three times the conductivity of copper along the fibers) really only come into play at temperatures far above what you could run an LED at.
> 
> I saw another exotic solution with some promise in a patent filing from a Taiwanese company. They sintered vacuum grown carbon fibers into a copper matrix. Supposedly the resulting material had excellent strength, machinability, and thermal conductivity in all directions.


 

Snarfer, have you had the opportunity to use any carbon/graphite filled thermal pastes? The claims I have seen say it can improve contact with a traditional heatsink material more effectively than regular metal filled thermal pastes, IE arctic silver. I wonder if the same is true with this as what you discovered, only at very high temps.


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## PhotonFanatic (Dec 8, 2008)

modamag said:


> Tellurium Copper is easy to machine. BUT! IT'S VERY DANGEROUS!
> 
> In my infancy I made couple PXR2 out of it.
> 
> What I would do for an affordable solution is to use diamond paste and aluminum backing. That way it'll get the heat away from the source quicker and not retain it (eg. copper)



Jonathan,

I think you are overreaching here--tellurium compounds can be mildly toxic, with the most serious problems arising from ingestion or injection. 

Inhalation could be a problem, but not from normal machining of tellurium copper--we aren't making dust, we're making chips. 

Simple precautions can be taken, i.e., wear latex gloves, long sleeved shirts, etc., even a respirator, if you were really worried, that should eliminate any problems with the machining of tellurium copper.


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## greg_in_canada (Dec 9, 2008)

starburst said:


> I alway's wanted to try silver, I got some .999 % around here somewhere.



This is my favorite homemade cooler on Overclockers.com (sterling silver) http://overclockers.com/index.php?option=com_content&view=article&id=4044&catid=52:cooling&Itemid=34

Greg


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## snarfer (Dec 9, 2008)

> have you had the opportunity to use any carbon/graphite filled thermal pastes?



I looked through lots of overclocking sites and stuff for some benchmarks and it seems that the actual performance difference between the best thermal paste available, and the cheapest thermal paste available is not more than a few degrees. Given that I had a relatively huge interface area (on a fixed lighting project) testing thermal paste quickly declined on my priority list.


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## KowShak (Dec 9, 2008)

snarfer said:


> I looked through lots of overclocking sites and stuff for some benchmarks and it seems that the actual performance difference between the best thermal paste available, and the cheapest thermal paste available is not more than a few degrees. Given that I had a relatively huge interface area (on a fixed lighting project) testing thermal paste quickly declined on my priority list.


I remember a thermal paste benchmark where they showed that toothpaste was significantly better than the best thermal paste, or at least it was before it dried out when it became worse.


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## VegasF6 (Dec 9, 2008)

KowShak said:


> I remember a thermal paste benchmark where they showed that toothpaste was significantly better than the best thermal paste, or at least it was before it dried out when it became worse.


 

I would have to imagine that was only because of the moisture? After all, wouldn't submerged in water be the best possible heatsink? Or frozen water  Or frozen gas....


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## qwertyydude (Dec 9, 2008)

Water is the best heat conductor it's why they use it for cars, with of course antifreeze and anticorrosion in a sealed system. The incredible heat capacity and heat conduction properties of water make it ideal but the fact that it dries out makes it only a short term solution. It's why toothpaste, vegemite, spit, and even chocolate syrup outperform the oil based stuff. At least until it dries out.


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## snarfer (Dec 10, 2008)

> The incredible heat capacity and heat conduction properties of water make it ideal but the fact that it dries out makes it only a short term solution.



Sort of. Actually water in liquid state has low heat conduction properties. See here. However the fact that it "dries out" is what makes it useful as a heat conductor. This is how heat pipes work, and how our bodies conduct heat to the atmosphere when we sweat. Heatpipes can use water, but other liquids/vapors can be equally or more effective, for example propane and butane are often used.

Bottom line is that a cooling solution such as for lighting has to be thought of more in terms of a total system rather than a particular construction material. You could make a flashlight out of a gigantic diamond, or a solid piece of copper, but that doesn't mean you'd have a good cooling system. In fact, I bet that you could outperform either of these with a construction made entirely out of plastic, but with better design.


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## qwertyydude (Dec 10, 2008)

I didn't mean water alone as a heat sink but as a thermal transfer compound. Water may not have the highest thermal conductivity but the fact that it can make perfect contact with the heat suface means it draws heat faster plus with it's high specific heat it won't get nearly as hot as quickly so that it cools better. If you look at all the other readily available liquids that you can use as a thermal paste of some sort water beats them by a fair margin.


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## yellow (Dec 11, 2008)

is there any comparison data between the capabilities of thermal paste vs. Arctic glue?


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## Blindasabat (Dec 12, 2008)

I made a table to compare materials recently when I looked into the best heat sinking material. I started just wanting to know if copper really was better than aluminum & brass for the same weight, but since I found tables of lots of materials, I just copied all of them into my Excel spreadsheet.

Then I combined the properties I was interested in (density, thermal conductivity, & thermal capacity) to get some factors addressing total thermal performance per unit weight and volume.

Copper wins by volume, and Beryllium wins handily over AL by mass, but Beryllium is somewhat hazardous to work with on an industrial scale and very expensive.

Copper-Alu is horrible, oddly enough.

<Edit> Table re-added as picture:


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