Thanks for the statement below, to help clarify this topic on BeO.
The pinkish ceramic on old RCA tubes was made by a company in
Frenchtown (NJ, NY, PA?), so was called Frenchtown ceramic. Sometimes
there is a purplish hue to it. Svetlana has some sort of similar
material, from another source. Manganese is in it. And yes, it is not
BeO. BeO is present in some conduction cooled connector blocks on
power tubes, and on the undersides of many RF power transistors,
between the device and the bottom flange. The white top cap is
usually alumina ceramic.
Eimac stayed away from using the pink ceramic for marketing reasons.
Technically, Frenchtown ceramic made very good tubes, and many of our
3MW triodes, Burle/RCA 7835, had pink. Nowadays they are all white.
Frenchtown is no longer available.
73 to all, and happy holidays,
Keep those fingers out of the HV, and don't crush and inhale BeO, and
watch out for DAFfy circuits!
John
K5PRO
At 11:46 PM -0500 12/21/99, Amps Digest wrote:
To: <amps@contesting.com>
>Date: Tue, 21 Dec 1999 08:53:45 -0700
>From: measures <measures@vcnet.com>
>Subject: Re: [AMPS] BeO Cautions
>
> >
> >Ian Roberts wrote:
> >>It should have been obvious what I was trying to say. The pure form of
> >>BeO IS white, but the manufacturers have licence to make it any colour
> >>that they please, from white to black, depending on what mix of
> >>"alumina", "silica", and "beryllia" and other compounds they choose to
> >>incorporate in the mix
> >>An amateur who assumes it has to be pure white to be BeO, such as
> >>urself, apparently, could be in for a nasty....
> >
> >That isn't what I said at all! I said that the pink colour has NO
> >CONNECTION with any beryllia content, so the colour is totally useless
> >as an indication.
>
>Ä Amen. Ceramic insulation in ceramic/metal tubes is silver-soldered to
>the metal parts. The pink colour is from a bit of Manganese that is
>added to improve the wetablility of the ceramic RCA and Svetlana were
>two tube manufacturers who used manganese.
--
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