16-07-1952 дата публикации
Номер: GB0000675594A
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Принадлежит:
... 675,594. Glass. BRITISH THOMSON-HOUSTON CO., Ltd., STANWORTH, J. E., and DALE, A. E. Sept. 15, 1950 [Nov. 11, 1949], No. 28962/49. Class 56. A glass composition comprises the following constituents in the respective percentage ranges by weight, P,O, 10-33, B 2 O 3 26-49, Al 2 O 3 15- 38, CaO, MgO, BaO together 15-25 and optionally SiO 2 less than 10, and alkali metal oxides less than 3. The preferred range is P 2 O 5 13- 20, B,O, 35-46, Al 2 O 3 20-29, CaO and/or MgO and/or BaO 15-25, SiO 2 less than 10, and Na 2 O and K 2 O less than 3, and an example contains P 2 O 5 16, B 2 O 3 39, Al 2 O 3 23, CaO 5, MgO 12, and SiO 2 5. The glass is resistant to alkali metal vapour and is used as a coating on boro-silicate glasses, e.g. SiO, 66, Al 2 O 3 2, B 2 O 3 24, alkali 8, to form composite glass envelopes for electric discharge lamps, the glass also being used to coat the exterior of the stem. The composite glass of the example given has a coefficient of expansion of the order of 50Î10-7 ...
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