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Subject: Sorry to say - but isnt copper as good a conductor ...
Name:
Celstk855
Date: 10/19/2001 7:17:32 PM (GMT-7)
IP Address: 210.84.108.100
In Reply to: Re: That much, really? posted by
 ludicrous
Message:
of heat as Ag?
My book here says...(Wcm-1K-1)
Al=2.4
Cu=4.0
Silver=4.3
at 25-75oC....
I wouldnt be quibbling over 0.3 in 4...<10% but if your chasing a degree or two - then might be important....maybe not worth the extra $$$ though.
Im not sure the statement - Arctice Silver is a better conductor of heat than Silver or Copper is valid Either....any figures for the stuff compared to the above - units provided.
I think the main advantage of the arctive silver stuff is that is provides neater interface for heat transfer by filling in any "asperities" that my be evident on the surface of both the HS and the Chip. If you can improve the contact by 20% with this stuff then that will make all the difference. Also its almost impossible to get stuff perfectly flat - so the compound will fill those microns of difference too.
So The Silver is good....Copper paste probably just as good - but "Arctic Copper" isnt as "cool sounding" (pardon the pun) as the "Arctic Silver" either.
The heat capacity issue isnt important unless your talking "non-steady state". If it has a high heat capacity the it will stay at the same temp for a longer time, so it will take longer to heat up and longer to cool down....could be problem in some cases....say if your've just over heated.
The holes.....well....filling them up could be argued as to be the same as filling your HS vanes with Silver compound too. If there is any air moving through the holes - then let it move - dont stop it by pluggin them!! Almost non sensical.
Anyway - that's my opinion. Im not an expert in Thermo but messed around with a 300tonne steel ladles and refractory modelling about 20 years ago....;>)most probably forgotten most of that. I do rememeber thermal diffusivity though and finite element analysis....
Anyway if I can have a look at a pick of one of these "holy" (;>) HS's then I would appreciate it.
my2c sorry 'bout the speeling.;>)
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