I am running a peltier element, and on the cold side an aluminum heat sink to effectively spread out the cool surface to the maximum possible surface area.
I just bought this new thermal paste: Coolermaster Nano, and whenever it touches the cold side of the peltier (less than 10 Fahrenheit) it freezes into a rock, while thermal paste such as Arctic MX-4 does not.
I had a hunch that this freezing affect was causing problem as temperatures using the Coolermaster Nano thermal paste were far far higher than the Arctic MX-4 (16 Fahrenheit vs 0). So, I ended up removing all thermal paste and saw that even with no thermal paste between cold side and heat sink, the temperature was lower than with using Coolermaster Nano, at 10 Fahrenheit.
I was wondering if someone could explain this to me: are some thermal pastes not designed or suited for low temperatures? Is there something I should look out for when purchasing a thermal paste (carbon based?)
Best Answer
Yes, of course. A thermal paste intended for CPUs is rarely used below 25C. You need to read their datasheet or search for cryogenic thermal compounds.
It is probably cheaper to select some of the consumer grade ones through their datasheet and test the best for your application. Arctic Silver 5, for example, claims to be stable down to -50C.