Artic silver corroding?

[DocClock aka MadClocker]

When I got my hot little cCO 700E, I took my alpha off my 600E, and when I took it off, I noticed that it (A.S.) had discolored...and I didn't have it on there but a couple of months, and now a freind had his cpu start to get too hot, and regreased his cpu (he is using A.S. as well) and the problem went away...have any of you had to "redo" your proc? and have you noticed the discoloration?
I am starting to think that about every two or three months, we should reaply the stuff, or at least inspect it.
So if you notice that your temps are rising (and not from the summer heat) suspect your A.S. compound.
Maybe Ed or Joe could take a survey on the subject...I think it might be worth while.

 

[Hoot]

Aside from recombining into small silver flecks, I've never seen anything out of the ordinary with older AS. The silver particles are passivated by being suspended in an oil based carrier, which keeps it from contact with air. Contact with moisture bearing air would be a source for bare silver corroding. Certainly an odd phenomenon you are experiencing.

Hoot

 

[Fink]

I noticed the same thing. I pulled my HS off after about 6 months and noticed that the AS had turned brown around the edges where it was in contact with the air. I also noticed that in one part of the contact area between the CPU and HSF, the AS had a very liquid look to it. And indeed when tilted this 'liquid' would slowly run to the low side.

This to me is rather ominous. It clearly indicates that (1) the AS is undergoing some kind of oxidation - which accounts for the brown coloration and (2) the AS appears to be undergoing some kind of separation of matrix and substrate.

how this effects cooling capacity, I don't know. But what I do know is that a CellII600 that used to run at 900/1.7V will no longer overclock at all, even after replacing the old HSF and cleaning off the old AS and reapplying fresh material. Could be anyone of a number of reasons for this though...

I would be very interested in hearing if anyone else had had this experence. And, if they had noticed any degradation of thermal performance over the course of a few months.

 

[Murphy]

Chemists

Fink (Apr 17, 2001 12:27 p.m.):
I noticed the same thing. I pulled my HS off after about 6 months and noticed that the AS had turned brown around the edges where it was in contact with the air. I also noticed that in one part of the contact area between the CPU and HSF, the AS had a very liquid look to it. And indeed when tilted this 'liquid' would slowly run to the low side.

This to me is rather ominous. It clearly indicates that (1) the AS is undergoing some kind of oxidation - which accounts for the brown coloration and (2) the AS appears to be undergoing some kind of separation of matrix and substrate.

how this effects cooling capacity, I don't know. But what I do know is that a CellII600 that used to run at 900/1.7V will no longer overclock at all, even after replacing the old HSF and cleaning off the old AS and reapplying fresh material. Could be anyone of a number of reasons for this though...

I would be very interested in hearing if anyone else had had this experence. And, if they had noticed any degradation of thermal performance over the course of a few months.

Hey Fink
here I am again, the fellow chemist. I have some AS @ home, but it arrived after I had my setup completed. I'm looking onto a big turn-around in one or 2 weeks and will apply the AS. Bad I don't have results very soon. A nice idea might be to run a XRD-spectrum of the brownish thing. I've seen a geologist in the forum with acces to a XRD, I can get one too maybe. Just some thoughts

Greetings!

 

[Fink]

My best guess for the brown stuff is some kind of oxidation of the oil based matrix carrier. This would make sense since it the AS is exposed to a high temp environment for a long time in an area where there may be ozone present. That, coupled with some kind of electrochemical reaction taking place between the 'silver' and the aluminum HSF, really leaves the door open for whatever this brown material is.

Once I find a job I might take the material, separate the carrier from the silver and run 1H NMR and GCMS to identify the components. CHNO analysis of the brown stuff compared to the original AS would also tell me if it is an oxidation process operating on the carrier matrix. Since there is no job anywhere in the future, guess it will have to wait.

 

[Nevin]

Hey guys,

A bright silver sticky grease in a windy, dusty environment is discolored over a few months when exposed to the air.

Think it through...

Nevin