Beryllium Oxide Heat Sink Compound

[Halcyon]

I have a small jar of BeO from years and years ago (sometime in the 90's). It hasn't dried out and still of usable consistency. I'm wondering, is it still any good to use after all this time or would it have lost its thermal conductivity properties? Should I just chuck it? I used to swear by the stuff for CPU's etc...

I also have a tube of Dow Corning 340 compound. Will this work just as well as a replacement for the BeO? Can BeO still be purchased by end-users?

[nctnico]

I'd dispose of it properly because it is pretty toxic stuff. If you want high heat resistance thermal compound then look for Sigraflex.

[Halcyon]

I'd dispose of it properly because it is pretty toxic stuff.

People seem to be scared of the stuff. Although it's classified as a carcinogen, the biggest threat to health is when its in a solid/powdered form. Inhalation and ingestion is bad. But in the form of a thermal grease, it's fairly harmless unless you go deliberately sticking it into cuts or eating the stuff. If you get it on your hands, washing is all that is needed. (Yes, I'm a nerd who reads MSDS's.)

It's a bit like asbestos; It's scary stuff, but when it's burnt it becomes denatured and no longer poses the high health risk as if it were fibrous.

Handled correctly with a bit of common sense; it's harmless.

[German_EE]

MOST things are harmless if handled with a certain degree of common sense including mercury and some radioactive materials. Unfortunately the Health and Safety people now rule the roost which is why a broken mercury thermometer now needs a full hazmat team for 'correct' disposal. Just think, I used to play with mercury when I was a kid.

Beryllium Oxide? If it's still a paste then it should still be safe for use on your own stuff. If you use it on someone else's equipment then attach a small warning label to the back just in case someone decides to eat it or use it as antiseptic ointment. I prefer Arctic Silver.

[wraper]

I prefer Arctic Silver.

I wonder why people still use it. Not the best or cheapest paste from Arctic cooling and it's conductive. MX-4 is cheaper, better and is not conductive.

[Ian.M]

I would say - make sure the jar is properly labelled as a schedule 6 poison and with the correct CAS number (1304-56-9) in case you pop your clogs and someone else has to deal with it, and only use it on equipment that you are not going to sell or give away, where an ordinary thermal compound isn't good enough, and as German_EE has pointed out, put a warning label on anything you use it in.

Would it be good practice to use a smear of neutral cure silicone round the edges of a heatsink joint using such a toxic compound to minimise the risk of it drying out, flaking and contaminating the area?

[TerraHertz]

It's a bit like asbestos; It's scary stuff, but when it's burnt it becomes denatured and no longer poses the high health risk as if it were fibrous.

Asbestos is dangerous because of the tiny size of the fibers, that can penetrate and disrupt cell function. Melt the fibers, and it's OK. Though, takes a pretty high temp to do that.

But Beryllium is an element. Toxic in itself. And BeO is very stable but carcinogenic for metabolic reasons. Very incorrect to suggest burning it will make it save. In fact burning BeO thermal paste would probably break down the binder and turn the BeO content into an airborne power - exactly the opposite of safe.

[Halcyon]

Very incorrect to suggest burning it will make it save. In fact burning BeO thermal paste would probably break down the binder and turn the BeO content into an airborne power - exactly the opposite of safe.

I didn't suggest that at all and I have no intention of burning it. I just made the point that hazardous substances can sometimes be safe in other forms.

My original question isn't regarding the safety of BeO, those aren't my concerns. My question is, will it still be suitable as a thermal compound after 20+ years? It shows no signs of "splitting" or drying out. I won't bother hanging onto it if it's gone "bad".

[SeanB]

Would still be usable, but only where you can not get access to the paste without tools. Apply using disposable gloves, as it will be adsorbed through the skin in the grease carrier, and will not be healthy. Best is to double bag it and dispose of as hazardous waste instead.

[Carrington]

The best stuff that I could try was:

PAD:
   Fujipoly SARCON XR-m 17W/mK 0.49ºCcm^2/W @ 100kPa (50X-m Series)

PUTTY: 
   Laird Technologies Tpcm 780 5.4W/mK 0.025ºCcm^2/W @ 350kPa (~ 0.2mm Thickness)
   Laird Technologies Tpcm 580 3.8W/mK 0.1ºCcm^2/W @ 300kPa (~ 0.2mm Thickness)

GREASE:
   Dow Corning TC-5026 2.89W/mK 0.032 ºCcm^2/W (Hard to find)
   Shin-Etsu X23-7783D 6W/mK 0.1ºCcm^2/W (Hard to apply)

The best by far, to use with CPUs GPUs or similar.


The BeO thermal conductivity is prety high ~200 W/mK, however, it supports high temperatures.

My question is, will it still be suitable as a thermal compound after 20+ years?

No idea!