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Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
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AFAIK due to it's toxicity Beryllium is only used inside packages between silicon and metal normally. I expect that any ceramic tile will not be Beryllium. I hope my assumption is correct.
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
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How about looking at the density of alumina and beryllia
Alumina is 4/3 heavier. There used to be a hook on the end of a triple beam balance to hang stuff on, like a string, so you could weigh irregular objects in water and shout Eureka - I have found it !
Registered Member #2261
Joined: Mon Aug 03 2009, 01:19AM
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Sulaiman wrote ...
AFAIK due to it's toxicity Beryllium is only used inside packages between silicon and metal normally. I expect that any ceramic tile will not be Beryllium. I hope my assumption is correct.
That's what I thought until I read the third post in this recent thread Look at its photo , a Heathkit leaflet warning that the transistor mounting insulator is Beryllium Oxide! First I've heard of it outside of semiconductor packages, apart from Argon Ion lasers!
I know I could use lots of complicated methods to distinguish it from Aluminium Oxide, but is there a quick and easy method?
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
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I think I have here 8 TO-3 beryllium oxide transistor insulating pads, they are around 3mm thick. I can't imagine anything else as thick could conduct the heat adequately.
Registered Member #2261
Joined: Mon Aug 03 2009, 01:19AM
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Grenadier wrote ...
Magnetrons typically are made with beryllium oxide ceramics.
Are you sure this is true of domestic microwave oven magnetrons as I would expect them to avoid using highly toxic materials in a domestic product, but to mark it clearly as hazardous if they do, and the few microwave ovens I've stripped had no warnings.
Also, I notice a remark referred to elsewhere in this forum that the 'pink' ceramic sometimes seen in magnetrons is Beryllium Dioxide according to Wikipedia is out of date as Wikipedia didn't mention this when I checked the link today.
Registered Member #2261
Joined: Mon Aug 03 2009, 01:19AM
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Dr. Kilovolt wrote ...
I think I have here 8 TO-3 beryllium oxide transistor insulating pads, they are around 3mm thick. I can't imagine anything else as thick could conduct the heat adequately.
I have some similarly thick ceramic insulators for TO-220 packages which I stripped out of old equipment.
I assumed they where Aluminium Oxide used as reliable high voltage insulators with sufficient thermal conductivity for the job.
Are they likely to be Beryllium Oxide even for a more recent transistor package style and no warning given?
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How do you distinguish Aluminium and Beryllium Oxides ceramics?
