| 摘要 |
1,226,523. Thermally crystallizable glass. CORNING GLASS WORKS. 13 Jan., 1969 [19 Jan., 1968], No. 1899/69. Heading C1M. A thermally crystallizable glass consists essentially of, by weight, 2-7% Li 2 O, 0-25% A1 2 O 3' 10-60% SiO 2 , 20-80% (Ta 2 O 5 + Nb 2 O 5 ) wherein the Nb 2 0 5 constitutes 0-20% of the glass, the said oxides totalling at least 90% of the weight of the glass. Suitable further compatible oxides specified are those of Zn, Mg, B, Na, K, Ca, Sr, Pb, P and As. A glass ceramic article may be prepared from the said glass by cooling a melt of the above glass below the transformation range and simultaneously shaping a glass article therefrom, and then heating to 750-1200‹ C. so as to cause crystallization. The heating step may be for “-48 hours. A preferred modified heating schedule is 700-900‹ C. for 1-6 hours, and then 900- 1200‹ C. for 1-8 hours. The crystalline phase of the glass-ceramic formed may be LiTaO 3 , beta-spodumene solid solution or beta-Ta 2 O 5 or mixtures thereof. The articles may be varied from transparent to opaque. |
