Re: QDX MOSFET Heat Sinks
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How would I dispose of broken BeO?? Not sure.? For the intact block, as-is, I'd just put it back in the PA deck after my testing is finished?and documented.? Maybe someday we can use diamond for a BeO substitute.
The last time I looked into BeO disposal, the consensus of answers was to return it to the manufacturer of the product that contained it, with "BeO" written on the package.? I'd have to recheck that now. ?
One known BeO problem is that some ceramic bodied RF transistors have beryllium in their ceramic packaging,?and for the most part they're not marked. ?"Pink ceramic" is not a sure-fire guarantee that a part has BeO -- for example, my plasma cutter has pink ceramic nozzles?but they fail the best non-destructive test for BeO, which is thermal conductivity.
To test, get a thermal diamond tester from fleabay -- about $15 -- and test your mystery ceramic against known radio porcelain, like a tube socket or coil form, ?The BeO will be highly conductive,the porcelain not so much.
73 Jim N6OTQ ? ?
Oh my, Jim...
How do you dispose of something like that?
JZ
Yes, Jim? that is correct. Some day it could wind up somewhere that has no such control. My conscience is quieter if I don't use it.
BTW, do you remember the BeO envelopes on high power transmitting tubes? Same safety consideration noted.
73, JZ
John,?
The article you cited includes this:
"the material (beryllium oxide) is safe to handle as long as dust is not generated during machining or handling."
73 Jim N6OTQ
Hi Don,
I had a similar thought, but then did a bit more digging.
I found that Kyocera also offers a similar thermal product called Q-Bridge:
Most of those are also Aluminum Nitride, although some are made of Beryllium Oxide, which is quite toxic.
Unlike most electrical insulators, which have very poor thermal conductivity, those two ceramics possess thermal conductivity on par with metals.
Pretty cool! (pardon silly pun :-)
This class of part could be extremely useful as the envelope gets pushed on cig-pack sized Ham radios!
73,? JZ
On Sat, Jan 6, 2024, 11:10?AM Donald S Brant Jr < dsbrantjr@...> wrote: On Sat, Jan 6, 2024 at 07:16 AM, John Z wrote:
The thermal wick chips I mentioned in the previous post offer an
interesting possibility for the future (especially if the price comes
down!)
Those "thermal wicks" sure look a lot like a regular chip resistor with no element; maybe that is exactly what they are.?
I wonder what the thermal properties of an ordinary high-value (1M?)chip resistor might be.....??
The few I looked into had alumina substrates; not as good as aluminum nitride but better than air or PCB material.
73, Don N2VGU??
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