| 摘要 |
A transparent glass consists essentially, in per cent by weight, of TiO2, 55-75; total BaO, CaO, SrO and/or MgO, 10-45; total SiO2, Al2O3, B2O3, GeO2 and/or P2O5, 0.2-8; ZnO, 0-35; CdO, 0-35; Bi2O3, 0-35; PbO, 0-35. Minor impurities, e.g. ZrO2, may be present. When CaO is present, at least one of BaO, SrO, MgO, ZnO, CdO, Bi2O3 or PbO is also present. The glass may be in the form of small beads with R.I. 2.1-2.9. All compositions remain vitreous when of size minus 100 mesh U.S. S. sieve, and many remain vitreous at minus 30 mesh. The beads may be formed by atomizing the molten glass while suspended in air. The beads may be used as retroreflexive elements, e.g. in conjunction with an organic binder of low R.I.
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