Non-opaque arsenic-free beta-spodumene glass ceramic exhibiting brown-grey coloration

Abstract

Methods, compositions, and articles provide for LAS-type glass-ceramics having specific thermo-mechanical, optical and coloration characteristics to yield generally brown-grey products. The glass-ceramic materials may include as colorants iron oxide, vanadium oxide, chromium oxide, cobalt oxide, nickel oxide and/or cerium oxide.

What is claimed is: 
     
         1 . A glass precursor composition, which when subject to ceramming exhibits a lithium aluminosilicate characteristic, containing beta-spodumene as a predominant crystalline phase, the glass precursor comprising, (in weight %):
 60-72% SiO 2 , 18-23% Al 2 O 3 , and 2.5-4.4% Li 2 O; and   
       0-0.3% V 2 O 5 , 0.05-0.4% Fe 2 O 3 , 0.01-0.04% Cr 2 O 3 , 0-0.05% CoO, 0-0.3% NiO, and 0-0.2% CeO 2 . 
     
     
         2 . The glass precursor of  claim 1 , further comprising (in weight %): 0-2.5% ZrO 2 , and 1.5-4% TiO 2 . 
     
     
         3 . The glass precursor of  claim 1 , further comprising (in weight %): 0-3% MgO, 0-3% ZnO, 0-5% BaO, 0-2% CaO, 0-1.5% K 2 O, 0-1.5% Na 2 O. 
     
     
         4 . The glass precursor of  claim 1 , further comprising (in weight %): 0-0.6% SnO 2 .