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Carbon Black Experiment?
- Thread starter whitehat_optix
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Freeloader,
The advantage to water as a TIM is that it evaporates and carries away heat.
The disadvantage to water is that it evaporates and eventually you have a dry joint and soon a dead CPU.
A TIM based on a fluid that evaporates at the temperatures within the thermal joint will give excellent short-term performance, but will not last more than a few minutes, hours or days depending on the evaporation rate.
You have a good memory. For heatsink testing on hardware sites, I have considered releasing a short-term use only thermal compound that does not require any break-in. Since it achieves optimum performance within a few minutes of application, it allows more efficient and consistent heatsink testing. The downside is that it only lasts a week or two at most.
Kind of like a sprinter versus a long-distance runner. For heatsink testing you want a sprinter type of compound. For use in the real world, you want a marathon runner.
Nevin
The advantage to water as a TIM is that it evaporates and carries away heat.
The disadvantage to water is that it evaporates and eventually you have a dry joint and soon a dead CPU.
A TIM based on a fluid that evaporates at the temperatures within the thermal joint will give excellent short-term performance, but will not last more than a few minutes, hours or days depending on the evaporation rate.
You have a good memory. For heatsink testing on hardware sites, I have considered releasing a short-term use only thermal compound that does not require any break-in. Since it achieves optimum performance within a few minutes of application, it allows more efficient and consistent heatsink testing. The downside is that it only lasts a week or two at most.
Kind of like a sprinter versus a long-distance runner. For heatsink testing you want a sprinter type of compound. For use in the real world, you want a marathon runner.
Nevin
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climbski,
A silver heatsink would offer very little advantage over a copper one, but would be many times the cost. Still it is always fun to consider the possibilities.
In high-end audio, (Where I spent 20+ years of my carreer.) the expressed ultimate dream was to design a speaker that was an infinitely small pulsating sphere. When I finally made one, I dropped it in the carpet and could never find it.
Nevin
A silver heatsink would offer very little advantage over a copper one, but would be many times the cost. Still it is always fun to consider the possibilities.
In high-end audio, (Where I spent 20+ years of my carreer.) the expressed ultimate dream was to design a speaker that was an infinitely small pulsating sphere. When I finally made one, I dropped it in the carpet and could never find it.
Nevin
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- Dec 29, 2000
This discussion while interesting/amusing is still in need of one clarification. The paper (which was written by Dr. Chungs Grad Student most likely BTW) has not yet been submitted for a formal peer review.
Here is a link that mentions that the paper is going to be published in the journal 'Carbon'.
http://www.sciencedaily.com/releases/2003/07/030714092651.htm
Dr. Chung (and presumably her grad student) are materials people and as such they may need some more expert help to be able to put these findings in a cooling perspective. The results really need to be reproduced and then 'poked and proded' by peers as well as other interested parties (like us) before we get to excited or factionalized by this.
I know we all want the latest greatest stuff but some times academic papers don't lead to any real world applications.
O
Here is a link that mentions that the paper is going to be published in the journal 'Carbon'.
http://www.sciencedaily.com/releases/2003/07/030714092651.htm
Dr. Chung (and presumably her grad student) are materials people and as such they may need some more expert help to be able to put these findings in a cooling perspective. The results really need to be reproduced and then 'poked and proded' by peers as well as other interested parties (like us) before we get to excited or factionalized by this.
I know we all want the latest greatest stuff but some times academic papers don't lead to any real world applications.
O
Nevin: I would love a quick settling paste. Most people who have the resolution needed for any sort of testing would.
All: There seems to be a backlash against this particular researcher on the forum for whatever reason. Dr. Chung has nearly 200 peer reviewed publications:
http://www.sciencedirect.com/scienc...=1069128&md5=be90d4735935ca482cee62e0d8676cf1
so it isn't just some kook clamoring for attention. Looks like the vast majority of her work deals with carbon additions to concrete though and not in the field of heat transfer. You should interpret the article that Owen just linked as saying "the research HAS undergone peer review, WAS accepted after consensus, and WILL BE published in the journal Carbon as soon as they can get to it. You don't say that a paper is to be published in a journal unless it has been reviewed and accepted.
All: There seems to be a backlash against this particular researcher on the forum for whatever reason. Dr. Chung has nearly 200 peer reviewed publications:
http://www.sciencedirect.com/scienc...=1069128&md5=be90d4735935ca482cee62e0d8676cf1
so it isn't just some kook clamoring for attention. Looks like the vast majority of her work deals with carbon additions to concrete though and not in the field of heat transfer. You should interpret the article that Owen just linked as saying "the research HAS undergone peer review, WAS accepted after consensus, and WILL BE published in the journal Carbon as soon as they can get to it. You don't say that a paper is to be published in a journal unless it has been reviewed and accepted.
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pHaestus,
You are right. But, even though it was peer reviewed for publication in Carbon, I doubt that it has been reviewed by the IC Component Cooling community. My point is that even though the testing of Carbon Black is perhaps under the materials specialty the application to CPU cooling is not.
The conclusions the paper makes are very far reaching, hence the controversey. Even after the paper is published people will need to reproduce the results. As I recall peer review does not usually include a reproduction of the tests, but I could be wrong.
O
You are right. But, even though it was peer reviewed for publication in Carbon, I doubt that it has been reviewed by the IC Component Cooling community. My point is that even though the testing of Carbon Black is perhaps under the materials specialty the application to CPU cooling is not.
The conclusions the paper makes are very far reaching, hence the controversey. Even after the paper is published people will need to reproduce the results. As I recall peer review does not usually include a reproduction of the tests, but I could be wrong.
O
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Reproduction of results is probably one of the most vital things in the porcess of disproving or proving hypotheses. Since it has not been broadcast to the scientific community yet, I think it would be a bit rash to critique or criticise her work. We do however have a rather unique perspective on the issue - we are her market audience. We also have access to her paper and more importantly the substances used in the production of her wonder TIM.
I say we mix some up and test it for ourselves. The components are not hard to come by and so with some decent measuring equipment (probably all we need is a pipette that measures down to 0.01cm^3 and a top-pan balance that does 0.001g precision - these should be available in most colleges) we should be able to get some results that we can convert to comparable numbers.
There are however some other issues with this TIM - first is the evaporativity of the solvents used - like Malpine Walls said, they will probably dry up fast in a hot CPU junction.We should also test the electrical conductivity of this stuff as well - just to be on the safe side. If this stuff is proven to be good on her claims then I think corporations and marketers can research some more into alternative solvents that do no dry out as easily.
I say we mix some up and test it for ourselves. The components are not hard to come by and so with some decent measuring equipment (probably all we need is a pipette that measures down to 0.01cm^3 and a top-pan balance that does 0.001g precision - these should be available in most colleges) we should be able to get some results that we can convert to comparable numbers.
There are however some other issues with this TIM - first is the evaporativity of the solvents used - like Malpine Walls said, they will probably dry up fast in a hot CPU junction.We should also test the electrical conductivity of this stuff as well - just to be on the safe side. If this stuff is proven to be good on her claims then I think corporations and marketers can research some more into alternative solvents that do no dry out as easily.
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- Dec 29, 2000
L337 M33P,
To use a term from your side of the pond, I believe. You are 'spot on!'
You have articulated what I did not. My concern is for our application (CPU cooling) not an academics lab test, so what better way to test it than to make some up and let someone test it with a die simulator, JoeC perhaps? Would he have access to the materials and apparatus? I can see a lot of issues with shippping the mixture premade as it might evaporate away if it were shipped. Perhaps if the mixtures were made and put in sealed containers they could be shipped and tested in a "grease off" a-la Dan's data?
O
To use a term from your side of the pond, I believe. You are 'spot on!'
You have articulated what I did not. My concern is for our application (CPU cooling) not an academics lab test, so what better way to test it than to make some up and let someone test it with a die simulator, JoeC perhaps? Would he have access to the materials and apparatus? I can see a lot of issues with shippping the mixture premade as it might evaporate away if it were shipped. Perhaps if the mixtures were made and put in sealed containers they could be shipped and tested in a "grease off" a-la Dan's data?
O
I stand corrected, got the info off of direction. com, obviously a missprint. In any event the whloe discussion here may be moot and we may all be using this in a couple of months URL=http://theinquirer.net/?article=10678]A better thermal interface, 70.0W/m°[/URL]
The smart lads at RNT have an interesting technology. They are working on a foil, composed of nano thin layers of aluminum and nickel, that when ignited, heats up to 1500° C in less than 10 milliseconds. Combine that with a bit of solder, and you can bond a heat spreader or heat sink directly to a chip without damaging the chip.
The bond is good for at least 70.0W/m°K.
An astute reader will notice that this is about 10 times better than the current best available solution. To use my favorite phrase, this is an order of magnitude better than anything else on the market.
The smart lads at RNT have an interesting technology. They are working on a foil, composed of nano thin layers of aluminum and nickel, that when ignited, heats up to 1500° C in less than 10 milliseconds. Combine that with a bit of solder, and you can bond a heat spreader or heat sink directly to a chip without damaging the chip.
The bond is good for at least 70.0W/m°K.
An astute reader will notice that this is about 10 times better than the current best available solution. To use my favorite phrase, this is an order of magnitude better than anything else on the market.
You would have to feel extremely strongly that someone was full of **** to go to the lab and try to reproduce experiments when reviewing a paper. I have on occasion run some calculations to suggest an alternate explanation to authors, but it would take weeks to get to the lab and try to do experiments myself.
I honestly hadn't read the whole paper in any detail and merely noticed the tables showing a range of applied force vs performance. If they are using a substrate that will quickly evaporate then this is of course not good for real world use.
I honestly hadn't read the whole paper in any detail and merely noticed the tables showing a range of applied force vs performance. If they are using a substrate that will quickly evaporate then this is of course not good for real world use.
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Owenator said:L337 M33P,
To use a term from your side of the pond, I believe. You are 'spot on!'
You have articulated what I did not. My concern is for our application (CPU cooling) not an academics lab test, so what better way to test it than to make some up and let someone test it with a die simulator, JoeC perhaps? Would he have access to the materials and apparatus? I can see a lot of issues with shippping the mixture premade as it might evaporate away if it were shipped. Perhaps if the mixtures were made and put in sealed containers they could be shipped and tested in a "grease off" a-la Dan's data?
O
Thank you
We could petition Joe for a test of the stuff, and the materials can probably be ordered online. Most of those chemicals used for solvents will be fairly widespread and most chemical retailers will have them. I don't think the stuff will evaporate quite like fairy gold, as in shipping cartons the temperatures don't get above 50C for example. My main worry was that it would evaporate in the high-temperature environment of an overclocked CPU.
As for the equipment, if colleges can own them then I think joe could at least rent the pan balance - the pipettes are as common as muck - we have 3 in a jar in a downstairs room on display
Malpine Walis
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Owenator said:
Do you think they can make it in Black?
Sorry to be a wisenheimer but I just couldn't resist. I haven't been sleeping much lately also ....
O
Black was, is and will always be cool. However, from google I learned that the most common substance for staining stuff black is Carbon Black. I also learned that Carbon Black is sold as an insulator in blast furnaces. It helps to keep all that expensively generated heat inside. Perhaps that is part of the reason why anything more than a vanisingly small amount of the stuff hurts the performance of Dr Chung's miracle compound.
I just got home from work and I have many active threads to look at so it may take me a while to hunt down the links. Check back later.
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When I tested the water as a T.I.M.,I encircled the Die with with a bead of thick non-conductive grease which created a seal to prevent evaporation. It is my theory that the water worked better because it was better able at filling the micro crevises in the heatsink and die and ,or it allowed a smaller gap with the two surfaces providing more direct physical contact. If the main strength of the carbon black is the small particle size, then this may explain why I saw an improvement with the water.
Now I'm not saying that people should use water, but that maybe we should look in a different direction for making a better paste. Potential evaporation of such a substance is easy enough to solve.
I thought of trying Fluorinert since it's like water but isn't conductive, but I don't know how to get a hold of some (and I'm too lazy to find out). Maybe someone more thermally obsessed than me will give it a try.
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What is the main reason for the short life? Is it evaporation? Do you think a makeshift seal would extend the lifespan?
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Freeloader said:
I'll try to explain this phonomena. I don't think evaporation is excatly the correct description. A better word would be boiling. At the temperatures a die reaches the water will be boiling. The effects of boiling on cooling are actually very good because water changing to a gas (what boiling is) is a great way to remove heat. I work at a power plant and we use this idea daily. We lwt the water just start to boil on the surface of our fuel this removes orders of magnitude more heat that simple conduction. In effect you have a convective cooling as well as the energy absorbed by the phase change from liquid to a gas. It is similar to the phonomena in a refrigerant system where the working fluid boils to absorb heat in the evaporator.
This is the single biggest problem I have with the paper. If you don't account for this kind of cooling effect CB looks great. If you realize that the physical state of the CB compound is changing and greatly affecting the cooling you realize that it dosen't directly compare to current thermal compounds that remain solid. It is kind of like saying that alcohol is better because it boils faster on my stove than water. But in realirty alcohol evaporates at room temperature so of course it boils easier. This does not however make alcohol a better coolant in a open room temperature system.
Does this make any sense? I am open for quesitons on this because water phase changes and water steam mixtures is what I do for a living whereas electronics cooling is my hobby.
BTW Did you see any water outside of the CPU core or did it stay where you put it. Actually it might have been converted to a gas and only been perceptable as a slight increase in the humidity in the air behind the seal.
O
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