ELECTROVACUUM GLASS Russian patent published in 1998 - IPC

FIELD: manufacturing of envelopes for high pressure fluorescent lamps, electrovacuum devices and other sources of light having high working temperature on the surface of their envelope during their operation; manufacturing of heat resistance dishes. SUBSTANCE: electrovacuum glass comprises, mas. %: silicium oxide having essential formula $$$, 76.5-80.1; boron oxide having essential formula $$$, 10.1-13.2; aluminium oxide having essential formula $$$, 1-3; sodium oxide having essential formula $$$, 2-6; calcium oxide having essential formula CaO, 0.5-1.5; magnesium oxide having essential formula MgO, 0.5-1.5; lead oxide having essential formula PbO, 0.5-2.5; cerium oxide having essential formula $$$, 0.1-0.3; at least one of oxides being chosen of arsenic oxide and antimony oxide having essential formula $$$ and $$$ respectively, 0.1-0.3. Softening temperature of desired glass is 690-717 C at viscosity $$$ Pa s. EFFECT: improved quality of desired product. 1 tbl