The Thermal Paste Revolution

arhines writes "ZZZ is running an article about an interesting new thermal paste which surpasses even solder in thermal conductance by 33 percent. If this paste makes it to the market sometime soon, we'll all surely be thinking about putting it in our boxes. In fact, if use of the paste becomes commonplace, it may even give the semiconductor industry a little speed boost."

Comments

Analysis

[fven]

This may help solve the problem that thermal compound applied badly is worse (in terms of temperature) than none at all.

In a thermal compound we are seeking somethng that:
(1) will conduct heat to the heatsink better than air
(2) will remain inert under extended high temperature exposure
(3) is non toxic (nice seeing as we have to deal with the stuff)

It is difficult for a material to conduct heat better than air if (large or many) air bubbles are present between the two surfaces, trapped by the compound itself.

So we all know how silicone performs, it meets 2 and 3 but there are some issues with 1, mainly because of the air bubble issue.

Carbon black, polyehtylene glycol and ethyl cellulose are both non-hazardous and ethyl cellulose is only mildly hazardous (Material Safety Data Sheets www.merck.co.th, criterion 3 met)
Particulate size is small (should lick the air bubble problem).
Spreadability should be a-ok (ethyl cellulose is a molding compound.
No polymerisation or other chemical reaction should occur (stable mixture, criterion 2 met).
Carbon is a brilliant conductor in this form ( criterion 1 met)

I think it'll work

Re: Actually...

[Fallen Kell]

Yep. If you peeled off that pad first, you would have probably gotten another 2-3 degrees. The pad uses a "wax-like" substance (i.e. a solid a room temperature, but liquid when lightly heated). The problem is with pads is that once you heat them after being installed, the wax-like substance just imbedded itself into all the microscopic cracks and holes on the top of both your processor and heatsink (doing its job). But now it is there, it doesn't just come off when you peel off that pad. It is there, and there pretty much for good, acting as a barrier between your heatsink and CPU and any other better thermal compound you use aftward.

Now, I didn't say it was there perminent, but it is close to it. You can get it off the heatsink, as you simply need to heat up the heatsink (a very hot hair-dryer will do this). Once you heat it up, you can start wiping the heatsink down with a cloth. Or you can lap your heatsink (use several grades of sandpaper to get a polished, flat, smooth surface, usually starting with 100-300 grit paper and working your way up to 1000-3000 grit paper, depending on how "anal" you are :) ). This will remove the outer layer of the heatsink metal as well as the microscopic cracks and holes on it, which will include your heat-pad substance.

The CPU is almost impossible to fully remove the heat-pad substance. You don't want to lap a modern day CPU, as all you will do is "create" microscopic cracks and holes. Modern CPU's are laser cut and pretty much perfectly flat. There are "some" cracks, but they are much smaller/finer then almost any sand paper you will ever find. You also risk damaging the CPU as the manufacturers now have traces and transistors located micrometers from the top of the CPU surface. Heating the CPU can easily damage it if you are not careful about how hot you let it get. So it is usually very dangerous for you to try to remove the substance from the CPU if you have not already done it several times (or don't mind wasting whatever you spend on that CPU when you need to go out and buy a new one).