Transparent, essentially colorless, tin-fined las glass-ceramics with improved microstructure and thermal expansion properties

摘要: The object of the present application is β-quartz glass-ceramics (having very interesting optical, thermal expansion and feasibility properties), articles including said glass-ceramics; precursor glasses glass-ceramics, as well methods for elaborating articles. Said having a composition, free, except inevitable trace amounts, arsenic oxide, antimony oxide rare earth which contains, expressed in percentages by weight oxides: 64 to 70% SiO 2 , 18 24% Al O 3 4 5% Li O, 0 0.6% SnO >1.9 4% TiO 1 2.5% ZrO 1.5% MgO, 3% ZnO, >0.3 CaO, BaO, SrO, with BaO + SrO ≤ %, Na 2% K 0.2 <(MgO O)/Li 1, P 5 less than 250 ppm Fe ; their crystallites, solid solution, have an average size 40 nm, advantageously 35 30 nm.