Heat sink question

hondgm · 2010-10-24T15:03:12+00:00

I've searched and searched and all I find are tests about exoticthermal pastes that PC overclockers use.What I'm wondering is: In general, is zinc oxide thermal paste orthese silicone pads better at heat transfer? This is for a TO-220voltage regulator. One problem is the pads I have are from a surplusdistributor so I don't have any technical info on it. For anyoneinterested, here they are hereThere is no need for electrical isolation between heat sink and thedevice. My instinct is the thermal paste is better.I really don't like when silicon gets hot to the touch, but maybe I'mbeing overly cautious. It's a 7805 regulator and it's dissipating maxof 1 Watt. My heatsink is about 20C/W no forced convection.

Oct 24, 2010 42 Replies

Rate this thread:

Tim Williams 15 years ago

Hmm, zinc oxide is ZnO. Zirconia is ZrO2 though.

Silicone grease should burn with a bright yellow flame, producing white "soot", which is silica fume. If it's starved for oxygen, black (carbon) soot will also be produced.

Tim

Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms

Vote

Fred Abse 15 years ago

Lots of things turn yellow when hot, but they don't all come in tubes marked "Heat Sink Compound".

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

Vote

PeterD 15 years ago

Typically a light silicone grease or silicone oil. Both are relatively insensitive to heat issues, and don't oxidize readily. Some are volatile however, and seem to 'vaporize' off over the years. We've all seen crumbly heat sink compound...

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required