β-quartz glass-ceramics with a controlled transmission curve and a high content of iron oxide and of tin oxide; articles in said glass-ceramics, precursor glasses

摘要

β-quartz lithium aluminosilicate (LAS) glass-ceramics contain neither arsenic oxide nor antimony oxide, are fined with tin oxide and include vanadium oxide, chromium oxide and a high iron oxide content (>1500 ppm), and have a controlled transmission curve. Articles such as cook-tops can be made from such glass-ceramics.

主权项

1. A glass-ceramic of the lithium aluminosilicate type, containing a β-quartz solid solution as the predominant crystalline phase and having for a thickness of 4 mm:
an integrated optical transmission, Tv, in the visible range, of 0.8 to 2%; an optical transmission at 625 nm of more than 3.5%; an optical transmission at 950 nm between 40 and 70%; and an optical transmission at 1,600 nm between 50 and 75%,wherein its composition, expressed as percentages by weight of oxides, comprises:
SnO2 0.3-0.6; V2O5 0.02-0.15; Cr2O3 0.01-0.04; Fe2O3 >0.15-0.32; As2O3+Sb2O3 <0.1; and Fe2O3/(V2O5*SnO2) 5-15.