| 摘要 |
A transparent glass which, at a thickness of 2 mm, does not transmit more than about 1% of ultraviolet radiation at a wavelength of 380 nm and exhibits a neutral gray, fixed tint bounded by apices A, B, C, D, A of the drawing, a purity no higher than 6, and a luminous transmittance between 10-16, said glass having a composition consisting essentially, expressed in terms of weight percent on the oxide basis, of SiO2 65-72 CaO 0-1.5 B2O3 2-6 Al2O3+caO 0.2-2.25 Na2O 6-10 AS2O3 0-0.3 K2O 10-16 Fe2O3 4.8-6.2 Na2O+K2O 17-23 CO3O4 0.012-0.02 K2O:Na2O 1.25-2.25 NiO 0.16-0.21 A12O3 0-2.25 ZnO 0-1.5.
|
