| 摘要 |
PROBLEM TO BE SOLVED: To provide a funnel glass for a cathode-ray tube whose demanded characteristic is satisfied when lots of glass pieces of valves for a cathode-ray tube are used as raw materials. SOLUTION: The funnel glass for a cathode-ray tube comprises, by mass, 48-62% of SiO2 , 1.2-4% of Al2 O3 , 16-21% of PbO, 0.2-2% of MgO, 0.2-4% of CaO, 3-8% of SrO, 3-8% of BaO, 0-2% of ZnO, 4-9% of Na2 O, 4-9% of K2 O, 0.3-2% of ZrO2 , 0-1% of CeO2 , 0-1% of TiO2 , 0-2% of Sb2 O3 , 0.03-1% of Fe2 O3 , 0.28-1.0 of (SrO+BaO)/PbO, 0.05-0.25 of Al2 O3 /PbO, and is characterized by 62 cm<-1> or more of X-ray absorption coefficient at 0.6Å.
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