MEDIUM EXPANSION LEADED COPPER BOROALUMINOSILICATE GLASSES

摘要

The present invention is directed at a leaded copper boroaluminosilicate glass, (20, 22) having coefficients of thermal expansion (CTEs) of between 25 - 55 x 10-7 / °C (over a range of 25-300 °C) and a softening point in the range of 550-725 °C, being suitable for use as a sealing glass, especially for borosilicate glasses, and having a composition consisting essentially, in terms of weight percent on an oxide basis, of 27-60 SiO2, 3-14 Al2O3, 9-28 B2O3, 0.0-10 R2O, 0.1-40 PbO, 0.1-11 CuO, where R2O is an alkali oxide selected from the group consisting of Li2O, Na2O, K2O, Rb20 and Cs2O.