Carbon Black Experiment?

[MILLTHERM]

Having actually soldered a heat sink to my test block I can tell you it outperforms ASGIII by a wide Margin. It appears that she also ran the same test and was 33% better.

Just because her baseline material comparison was not your prefrence does not make it any less valid.

Chung besides a solder junction comparison, also compared other graphite material some of which are probably close to copper. (do a google on graphite heat sinks = to copper)

do a google on carbon black, it can be bought - try you copier toner .03 particle size
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

"All thermal pastes previously reported are inferior to solder in providing high thermal contact conductance. By using carbon black as the thermally conductive ingredient, we have attained thermal pastes that are superior to solder in providing high thermal contact conductance."

conductive solid
0.46 MPa
0.69 MPa
0.92 MPa
Carbon black
18.94 „b 0.60
24.87 „b 1.00
25.74 „b 1.20
Graphite (5 ƒÝm)
3.03 „b 0.09
3.67 „b 0.08
4.02 „b 0.12
Graphite (1 ƒÝm)
1.52 „b 0.03
1.77 „b 0.04
2.04 „b 0.05
Nickel (3 ƒÝm)
1.85 „b 0.05
2.14 „b 0.02
2.84 „b 0.04
Nickel (1 ƒÝm)
0.91 „b 0.07
2.03 „b 0.10
2.66 „b 0.03
Diamond (25 ƒÝm)
1.15 „b 0.02
1.21 „b 0.09
1.54 „b 0.03
Carbon filaments (0.1 ƒÝm diameter)
1.09 „b 0.03
1.32 „b 0.02
1.51 „b 0.03
Single-walled carbon nanotubes*
13.5 „b 0.2
13.8 „b 0.3
14.1 „b 0.4

 

[AFIsoldier]

i wish i was smart..then i would understand this stuff....

 

[Malpine Walis]

i wish i was smart..then i would understand this stuff....

Then I have to ask you to trust me. You are being asked to assume that dog **** is the same as gold.

 

[LazyBratsche]

Then I have to ask you to trust me. You are being asked to assume that dog **** is the same as gold.

Not really. The whole point of publishing papers is so that others can see the results, run tests themselves, and either confirm or refute the conclusion. If you _read_ the article, or skimmed through the paper, you would have seen that Dr. Chung hypothesized that properties other than conductivity ("conformability" and "spreadability") make a good thermal interface. All I (and most of us here) can say about that is that the ideas of "conformability" et al. make some sense, even if we don't know they are absolutely true.

Dr. Chung says this stuff is better than solder. It's generally accepted that solder is better than the various thermal goops. Her claim is now up for peer (and our...) review. A few more ambitious/crazy tweakers here are gonna try making a carbon black compound. Dr. Chung has a patent on it... so she's probably gonna develop a carbon black compound in the near future and market it. _Then_ the big tweaker sites are gonna test it, against known and respected compounds, and it'll be available to the rest of us. Until then, calling it "dog ****" is just a sad attempt at a flame. And at that point, it'll be pretty obvious whether or not the carbon black compound is an improvement over AS3 and company. So even then, your flames will be pointless.

Let's keep this discussion rational... this is a new and interesting developement for us.

 

[kct2]

There is one assumption that was made in error in the front page article. .46-.92 MPa is not an unrealistic amount of pressure to be applied to a CPU.

AMD specs show an acceptable force of 24lbf on the core (up to 30lbf for a 6 point clip). The core has an area of ~80mm^2 to ~130mm^2 depending on model.

Pa = N/m^2
MPa = 1,000,000 Pa
24lbf = 106.76 Newtons
130mm^2 = 0.00013 square meter

therefore:

a 24lb force on a 130sq.mm core = 821,230 Pa = .82 MPa
a 30lb force on a 80sq.mm core = 1,668,125 Pa = 1.67 MPa

So we already have a significant pressure on the CPU cores. Similar to the pressures used in the research paper.

(check my math incase I really messed something up)

AMD Tech Doc



I've got alot more on this, but need to think about it more (less beer). We need the technical forum back!

 

[Owenator]

Seems really moot anyway

I have been looking into this, read the article, google'd etc. AS3 says that the Thermal Resistance of AS3 if 0.004 in^2*C/W. If you invert this it's 250 W/in^2*C. Convert inches to meters you get 387500 W/m^2*C or as listed in the paper 38.75x10^4 W/m^2*C. Bottom line AS3 is still better than the best CB mixture which was only 29.63x10^4W/m^2*C. It is just a matter of looking at the options out there with the same units and then you realize that so far CB compunds don't appear to be any better than the current state of the art. To top it all off the stuff is electrically conductive which makes me more than a little nervous about putting it on my cpu. A better solution is a flat heatpipe that spreads out the heat and makes your heatsink more effective. http://www.thermacore.com/thermabase.htm

O

 

[MILLTHERM]

Probably one of the more hotly debabated issues between TIM manufacturers is the thermal resistance measurement and calc. with little agreement anywhere. Statements that one is better than another are really moot. A problem with comparison testing as noted by Bill Adams the water king, You need a fair level of sophistication in test equipment and method to get worthwile results.

I actually get better results with CoolingFlow than ASGIII, approx. 1.8 C @ 60 watts consistantly on hundreds of tests over the last couple of years. Most on the people forums can not measure the difference between the two lacking equipment and method. Some other phase change materials are quite good also and should not be discounted


as pointed out this is open for peer review anybody can follow Chung"s findings on thier own. It may be good, it may not

A note of caution if you do. From her paper results are sensitive to minor variations volume and mixing procedure. If you do not get the result I would examine your procedure very carefully before drawing any conclusions.

Flat heat pipes from the data I have seen offer only marginal improvements. Thermacore heat sinks would not be a favorite among overclockers as most of the high perf. OC sinks beat it hands down.

From the Paper I actually find Chung's Idea of Carbon black as a filler used with a fluid in a heat pipe more interesting.

 

[Nevin]

MILLTHERM,

That would be the Cooling Flow that you are listed as a US distributor for, right?
http://www.coolingflow.com/distributors.htm

Nice pimp Andy. Been learning from Nanotherm have you?


Nevin

 

[pHaestus]

Nevin: Calling out people on the ulterior motives in their posts works both ways doesn't it? Millennium-thermal used to ship heatsinks with Arctic silver products in the past and have now switched to cooling flow, correct? And so I guess there would be a pretty strong motive for you to suggest that Andrew switched for financial reasons instead of performance ones.

I have always found Andrew's performance claims regarding his heatsinks to be pretty reproducible. I don't see why he would go out of his way to make up numbers to market thermal paste for which he's just a distributor. If he were making up numbers then it would make a lot more sense to do so for the products he manufactures.

Just playing devil's advocate here; I have never even used Cooling Flow.

 

[MILLTHERM]

Actually I Am not a PIMP

Nevin,

My last shippment of CoolingFlow went out to BILL ADAMS almost a Year ago. Despite being listed as a distributor on their site that is an assumed license on their part, I have no futher connection financial or otherwise, I no longer sell retail and nobody could buy it from me if they wanted to.

Any present or future products I sell are/will be of an OEM nature and not nanotherm,ASG or coolingflow

I Just Like the paste, Do you have a problem with that?

 

[kct2]

It seems the papers main point is that a material with inferior thermal properties, but far better spreadability/compressibility will show better heat transfer. The other materials used forced a significant gap between the plates, making it all but impossible for any metal to metal contact. The carbon black allowed the copper to touch copper on the other side. Makes sense.

Now, would AS3 allow this same thing to happen? Would the silver cause the same gap as the diamond or nanotubes? Is the silver small/malleable enough to fill the pits and not prevent surface to surface contact? Obviously core to copper is better than core to silver to copper. Same questions for any other commercial thermal compound.

Also this is a test of transient heat transfer; the copper plate is heated by a laser impulse, this test was finished in milliseconds. How will the carbon black based compound hold up to hours to years of steady state operation? Assuming Malpine Walis is right, and I think he is, the PEG will quickly evaporate, what will hold the carbon black powder (electrically conductive) in place once that is gone? It may stay in place with the heatsink on, but take that off and there could be conductive powder covering random parts of your computer.

Why not use a solder with some silver content? Or silver instead of nickle. It doesn't make the carbon black results less valid, just the comparison less meaningful.

“Chung is in the process of filing a patent for the thermal paste through the UB Office of Science, Technology Transfer and Economic Outreach (STOR).” Source http://www.buffalo.edu/news/fast-execute.cgi/article-page.html?article=63270009

That makes me think Dr. Chung will not own the rights to this product, chances are SUNY Buffalo will. I know universities generally own the rights to student’s work, and I think it goes for Professors work also. UB is listed on the research paper, which makes me think they paid for it, therefore own it. I could be wrong if her contract specifically gives her rights to her research, otherwise UB most likely owns this. Either way I would expect this patent to be sold to someone else and further research done, possibly followed by marketing. Even if this does turn out to be a great product I wouldn't expect to see it distributed for a number of years.



Edit: BTW - MillTherm I have one of the original Glaciators and am sad to hear you aren't selling anything retail anymore, you made a quality product.

 

[pHaestus]

Universities typically own all intellectual property that is developed by researchers. You have to sign those forms before you get benefits

 

[Nanotherm]

It appears that the thermal resistance of this thread is increasing rapidly, so it may be a good time to clean things up, re-apply your favorite TIM and cool the conversation down a few degrees

 

[Malpine Walis]

Re: Seems really moot anyway

I have been looking into this, read the article, google'd etc. AS3 says that the Thermal Resistance of AS3 if 0.004 in^2*C/W. If you invert this it's 250 W/in^2*C. Convert inches to meters you get 387500 W/m^2*C or as listed in the paper 38.75x10^4 W/m^2*C. Bottom line AS3 is still better than the best CB mixture which was only 29.63x10^4W/m^2*C. It is just a matter of looking at the options out there with the same units and then you realize that so far CB compunds don't appear to be any better than the current state of the art. To top it all off the stuff is electrically conductive which makes me more than a little nervous about putting it on my cpu. A better solution is a flat heatpipe that spreads out the heat and makes your heatsink more effective. http://www.thermacore.com/thermabase.htm

O

Thank you Owenator.

I could not remember how to do that calculation. What initially raised my eyebrows about the research paper was the materials that Dr. Chung used for comparasion to her CB mixture. There is a reason that nobody makes heat sinks from nickle. Above I posted a link to a periodic table with thermal conductivity of the various elements listed. So why would you use it for a thermal interface material?

The list of different materials reminded me of an old commercial for Skippy peanut butter where various actresses dressed as soccer moms asked retarded questions like "Does a baloney sandwich have as much protien as a skippy peanut butter sandwich?"

Of course not! Everyone knows that peanut butter is loaded with protien and baloney is deficient in comparasion. So (offering no academic slight) Dr. Chung appears to have written a paper about her new wonder mixture and compared it to samples of materials that her CB mixture is clearly superior to.

LazyBratsche:

You do make a valid point about the nature of research. However, it remains that CB is not a very good substance for use in cooling applications. In fact, thanks to some googling, I learned that it is sold commercially as a thermal insulator. In her paper, Dr. Chung even stated clearly if she used more than 1.25% CB in her mixture themal performance dropped rapidly. This leads me to think that the PEG plays a rather larger role than indicated.

 

[Lord_MiL]

I just read through the paper and she mentions solder several times. I have always wanted to try soldering a heatsink directly to a CPU just to see if it would work without killing the CPU but haven't had an extra chip floating around for a while. Another idea I had once was to use Indium which is a good thermal conductor and can be cold welded (it'll bond to things with enough pressure and no heat) but Indium is insanely expensive.

So, has anyone ever heard of someone successfully soldering a heatsink or WB to their chip? After reading Dr. Chung's paper, I am interested again and might have to pick up one of those cheap 1700's and try!

 

[MILLTHERM]

Just to note Nickel oxides are a component of several white greases currently used, radio shack for one. combined with silicon oxides they are quite effective ASGIII generally beats them out at only a degree ot two at 60W.

Sometimes the whole is greater than the Parts.

 

[Nevin]

Radio Shack heatsink Compound: (From MSDS)

Chemical Percent
Zinc oxide 30
Polydimethylsiloxanes (Silicon oil) 70

Like most inexpensive thermal greases, Radio Shack compound is zinc oxide suspended in silicone fluid.

It does not contain any nickel.

http://support.radioshack.com/support_supplies/doc2/2885.HTM

Nevin House
Arctic Silver, Inc.

 

[climbski]

I just want a good SILVER heatsink...Thats all I'm askin for.

 

[Nanotherm]

MILLTHERM,

Your point about the 'synergy of materials' (or the whole being greater than the sum of parts) is quite valid. Nickel oxide wouldn't be one my first (or second) choices for a synergistic component, though.

For anyone who may be interested, here's a link to the "Thermal Properties of Materials" page from MIT's AI Lab site, which is a compact and handy reference to the thermal conductivities of many materials (including air) - http://www.ai.mit.edu/people/tk/tks/tcon.html. Simply multiply the reference numbers by 100 to get W/m-K.

 

[Freeloader]

By kct2: It seems the papers main point is that a material with inferior thermal properties, but far better spreadability/compressibility will show better heat transfer. The other materials used forced a significant gap between the plates, making it all but impossible for any metal to metal contact. The carbon black allowed the copper to touch copper on the other side. Makes sense.

After testing water for a T.I.M., I noticed a 3C improvement over AS3, even though water is about 15 times less thermally conductive. This was with a athon xp @1830 and 1.95 volts. I repeated the test several times (4 each) and came up with the same results.

Now I'm fully aware of the problems with using a motherboard for testing, but nothing else I ever did gave me such a large change. The cpu temps were compared to a constant water temp of 20c in all tests.

It's for the reasons in the above quote that I think the improvement occured, but one could argue that poor as3 aplications were to blame. So has anybody else ever tested water for a T.I.M.?

Question for Nevin: Didn't you make mention of a paste that you were working on that showed a few C's improvement over AS3 but had a short applied lifespan? About 2 month if I remember right. The paste was supposed to be thinner and didn't require settling. I think the idea at the time was to come up with a paste for testing purposes, if my memory serves me correctly. (it usually doesn't)