http://216.33.240.250/cgi-bin/linkr...n=http://www.pocothermal.com/html/whatis.html
This is a link to a graphite foam material that may be applicable to heatsink apps.
Tony D.
This is a link to a graphite foam material that may be applicable to heatsink apps.
Tony D.
Bad link.
Foams in general do NOT make good heatsinks compared with the solid materials. "Normal" graphite is good for refractory applications (not an issue here, we're not running at 1200 Kelvin), but its thermal conductivity and heat capacity are rather mediocre compared to metals. The exception is pyrolytic graphite parallel to the molecular planes, but the anisotropy (about 1000:1) makes it impractical as a heat sink
The best conductor is still diamond. If I can convince deBeers to send me free samples...
Foams in general do NOT make good heatsinks compared with the solid materials. "Normal" graphite is good for refractory applications (not an issue here, we're not running at 1200 Kelvin), but its thermal conductivity and heat capacity are rather mediocre compared to metals. The exception is pyrolytic graphite parallel to the molecular planes, but the anisotropy (about 1000:1) makes it impractical as a heat sink
The best conductor is still diamond. If I can convince deBeers to send me free samples...
Sorry about the link, here it is:
http://www.pocothermal.com/html/whatis.html
I am not all that familiar with these types of foams although I think this may be a new type that can be used for heatsink apps.
SY, thanks for the info., I just wish I knew what you are talking about
.
P.S., one of the apps. mentioned on the website is cooling of electronic devices.
Tony D.
http://www.pocothermal.com/html/whatis.html
I am not all that familiar with these types of foams although I think this may be a new type that can be used for heatsink apps.
SY, thanks for the info., I just wish I knew what you are talking about
.P.S., one of the apps. mentioned on the website is cooling of electronic devices.
Tony D.
Believe it or not, I was in contact with PocoFoam about 4 years ago (IIRC) talking with them about this technology with regards to forced air cooling of cpus. At least back then, the cost was overwhelmingly prohibitive - like $150usd for a 3" cube of the material. They've likely gotten their production costs down some, but it's not going to replace or be any better than good 'ol aluminum any time soon.
I have a friend at Imperial College in London who is a metallurgist, he has a colleague who is working on this, no details at present because he is waiting for patent approval, but he has promised to get me some samples to try out.
Apparently they have a new technique that can cut the size of heatsinks by up to half, using some sort of esoteric foamed aluminium alloy, the efficiency gains being made by the doping of the ally with various other elements, and a new way of making open cell foams.
Apparently they have a new technique that can cut the size of heatsinks by up to half, using some sort of esoteric foamed aluminium alloy, the efficiency gains being made by the doping of the ally with various other elements, and a new way of making open cell foams.
These types of technologies will probably be of large benifit to Space research, the military and the Space Station and with any luck there will be some trickle down effects for us Earth bound folk as well.
-----------------------------------------------------------------------------------
fdegrove- graphite/carbon is actually an excellent electrical conductor, I use carbon extensively in my RC gliders and I have experimented with using carbon tow as an interconnect, the problem is attaching it to the RCA's.
Tony D.
-----------------------------------------------------------------------------------
fdegrove- graphite/carbon is actually an excellent electrical conductor, I use carbon extensively in my RC gliders and I have experimented with using carbon tow as an interconnect, the problem is attaching it to the RCA's.
Tony D.
CONDUCTIVITY
Hi,
Electrical conductivty is one thing ability to convect heat is quire another.
I'm aware that A.J.Van den Hul prososes this type of conductor but on a resistance per running meter graphite/carbon compostions don't fare that well.
Remember carbon composition resistors?
Which doesn't mean it can't sound O.K.
And as you state it yourself,connenecting them to plugs is a PITA.
Cheers,
Hi,
Electrical conductivty is one thing ability to convect heat is quire another.
I'm aware that A.J.Van den Hul prososes this type of conductor but on a resistance per running meter graphite/carbon compostions don't fare that well.
Remember carbon composition resistors?
Which doesn't mean it can't sound O.K.
And as you state it yourself,connenecting them to plugs is a PITA.
Cheers,
Diamond heatsinks
SY, I wouldn't have believed the diamond heatsinks item if I hadn't actually held one. This stuff is incredible. It was demonstrated to me using an ice cube held against the edge of a 1cm square with my finger on the opposite edge. I could feel the drop in temperature on my fingertip almost immediately.
Unfortunately I couldn't persuade them to part with an amount sufficient to my Aleph needs. Something about cost and military use....Hmmmm!
Paul
SY, I wouldn't have believed the diamond heatsinks item if I hadn't actually held one. This stuff is incredible. It was demonstrated to me using an ice cube held against the edge of a 1cm square with my finger on the opposite edge. I could feel the drop in temperature on my fingertip almost immediately.
Unfortunately I couldn't persuade them to part with an amount sufficient to my Aleph needs. Something about cost and military use....Hmmmm!
Paul
any heatsink would be slaughtered by a diamond heatsink because diamond conducts heat through covalent bond lattice vibrations not molecular collisions this is much more effiecient but until the price of diamond comes down or CVD technology improves it is sort of out of reach.
BTW CVD is chemical vapour deposition.
Where the diamond is synthetic and essentially created on a material.
BTW CVD is chemical vapour deposition.
Where the diamond is synthetic and essentially created on a material.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.