Diamond TIM

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A DIY – Joe

I happened to come across some diamond powder and thought it might be interesting to see what it could do mixed with some plain white thermal grease. Diamond has terrific thermal conductivity – far better than the usual suspects:

Thermal Conductivity of Selected Common Materials

Material

Thermal Conductivity (W·m-1·K-1)

Diamond

895-2300

Silver

429

Copper

386

Gold

317

Aluminium

237

Air

0.0262

Up to four times better than silver – impressive!

The reason diamond is so much better has to do with its crystalline structure – apparently the strong linkages within this matrix conducts heat very efficiently; it also accounts for its other properties, such as its hardness.

The diamond powder I used was 9 microns in diameter – there are many sizes available, including sub-micron diameters. It looks like a fine, gray talcum powder. This material is not cheap, so I only tried the 9 micron size. I used a Glaciator Lite on the die-tester for this test – results below:

The Test

Thermal Grease

Die Temp

Ambient Temp

Delta

Plain White

45.2

22.2

23.0

Diamond + White

47.5

22.5

25.0

This was the best I could do after trying various mixtures – this was about 1 part powder to three parts white grease – other mixtures were worse.

CONCLUSIONS

Making thermal grease is a lot more than just mixing some stuff together – it takes time to test out various formulations, not to mention life-cycle testing. Diamond’s thermal properties are tantalizing and I bet there’s a way to make a superior TIM with it.

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