Thermal Grease

[Scott Johnson]

I have seen ZnO in silicone grease, Indium washers, BeO washers, plain
silicone grease, and ZnO in petroleum grease, but NEVER BeO grease. Some
space hardware does, however make use of beryllium metal (it is light and a
good thermal conductor) as a backplane material.  It was used in Motorola's
Iridium program.
Scott
----- Original Message -----
From: "J. Forster" <jfor at QUIK.COM>
To: <BOATANCHORS at LISTSERV.TEMPE.GOV>
Sent: Wednesday, November 03, 2004 9:44 PM
Subject: Re: Thermal Grease


> It is possible that at one time BeO was used in grease, but I've never
> seen it and
> I've been using the stuff since 1963. I very much doubt it's in commercial
> use
> anymore. In the late 60s, I was using BeO washers on TO-3 transistors.
>
> FWIW,
> -John
>
>
> Garey Barrell wrote:
>
>> Wes -
>>
>> That makes me feel better.   I thought I remembered beryllium oxide
>> grease.  NASA certainly was well above us "mere mortals!"   At least in
>> the 60's when I was there...
>>
>> Garey - K4OAH
>>
>> W. Kranitz wrote:
>>
>> >
>> > The "new" style white silicon grease is called "Type Z9"
>> > Silicon Heat Sink Compound. Some special application versions
>> > of this compound used beryllium oxide, but these were not available
>> > to us mear mortals. Most common versions use aluminum or zinc
>> > compounds. Some of the newer types use Micronized Silver (eg, DYNEX
>> > Silver Thermal Compound). These are used for the high heat transfer
>> > needed for modern microprocessors.
>> >
>> >
>> > Garey Barrell wrote:
>> >
>> >> Jerry -
>> >>
>> >> There are at least two types that I am aware of.
>> >>
>> >> The "old" style was clear silicone grease.
>> >>
>> >> The "new" style is white silicone grease loaded with beryllium oxide.
>> >>
>> >> Both work pretty much the same, the purpose being to fill any  TINY
>> >> air
>> >> pockets trapped between what ideally would be two "perfectly" flat
>> >> surfaces.  The idea is that the grease is a better at heat transfer
>> >> than
>> >> air.  It is NOT a better conductor than metal, so a big blob of grease
>> >> isn't going to transfer much heat between two surfaces that don't
>> >> touch.!
>> >>
>> >> Proper use calls for only a VERY thin smear.  Most people use WAY too
>> >> much, which of course gets squeezed out when the two pieces are
>> >> clamped
>> >> together.
>> >>
>> >> By the way, beryllium oxide DUST is considered very toxic if inhaled,
>> >> so
>> >> I guess you wouldn't want to eat the stuff!
>> >>
>> >> 73, Garey - K4OAH
>> >> Atlanta
>
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