RE: Beryllium Oxide

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jan Wagner <jwagner@xxxxxxxxx>

Hi list,

On Sat, 30 Dec 2006, Tesla list wrote:
> Original poster: "Breneman, Chris" <brenemanc@xxxxxxxxxxxxxx>
>
> I think that sometimes BeO is used instead of that white ceramic 
> insulator. From the wikipedia article on "Cavity magnetron", "Some 
> magnetrons have ceramic insulators with a bit of beryllium oxide 
> (beryllia) added-- these ceramics often appear somewhat pink or 
> purple-colored (see the photos above)."  One of the two photos above 
> is a picture of a microwave oven magnetron, with a pink 
> insulator.  I actually finished taking apart a microwave oven today, 
> and its insulator is purple-ish.

I too have taken apart a few older and some quite new ones, most did 
have a purple-ish insulator. Also chipped one apart once to see how 
the entire magnetron works, quite dusty business that was (and it was 
prior to knowing about beryllium, argh...)

Anyone on the list have any definitive info on whether BeO is really 
used in microwave ovens? Before the RoHS?

At least in the ovens I disassembled there were always just the usual 
yellow warning stickers about HV and about a charged capacitor, no 
other warnings.

Never any of those "this product contains beryllium" "highly toxic" 
type of stickers found on RF components or equipment that contains beryllium.

With beryllium warning stickers absent, and the ovens being consumer 
products for preparing food, it would seem odd if there really was 
any beryllium used. Or?

(Could be too good material for a lawsuit in the US where too hot 
coffee is sufficient to start one AFAIK ;-)

OTOH on second hand components and materials like used in coiling 
such warning stickers can very well be missing e.g. rubbed off and so 
on... :-| Would be quite cautious with machining those if they have 
ceramics that feel cold/metalish to the touch.

cheers,
 - Jan