Re: [Amps] pink ceramics

["Ian White, G3SEK" <G3SEK@ifwtech.co.uk>]

John T. M. Lyles wrote:
> Pink ceramic was high in magnesium content I believe.

From http://www.svetlana.com/docs/tubeFAQ.html

Q. Why is your ceramic pink?
A. Svetlana ceramic power tubes are manufactured with high-purity, 
high-alumina ceramic with chromium and manganese additives. The 
combination of chromium and manganese with high alumina ceramic results 
in a true chemical bond in the metal-to-ceramic brazing process. These 
additives also give Svetlana ceramic tubes their distinctive appearance. 
The stronger bond allows a higher processing temperature than typically 
used by manufacturers in the West. A high-temperature bake-out process 
drives gasses from the internal electrodes during vacuum processing. 
Clean high-temperature processing means long operating life


> It came from the Frenchtown ceramic factory, and was used by RCA for 
> many years on their expensive Cermelox tetrodes and other big tubes (up 
> to $100K in value). Purple/pink hue came in some Russian tubes from 
> their own similar source. The US source has dried up, and now alumina 
> ceramics come from others like Coors

Peter and I both knew that stuff wasn't fit to drink.


--
73 from Ian G3SEK         'In Practice' columnist for RadCom (RSGB)
                           Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek
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