Patent ID: 6043171
Filing Date: 2000-03-28
Classification: C03C

Abstract:
A lead-free and cadmium-free glass composition for glazing, enameling and decorating glass or glass-ceramics containing high quartz and/or keatite solid solution crystals as principal crystalline phases after crystallization and having a thermal expansion coefficient of less than 2.times.10.sup.-6 /K at temperatures between 20 and 700.degree.C., wherein the glass composition contains Li.sub.2 O, 0 to 5% by weight; Na.sub.2 O, 0 to 5% by weight; K.sub.2 O, less than 2% by weight; MgO, 0 to 3 by weight; CaO, 0 to 4% by weight; SrO, 0 to 4% by weight; BaO, 0 to 4% by weight; ZnO, 0 to 4% by weight; B.sub.2 O.sub.3, 15 to 27% by weight; Al.sub.2 O.sub.3, 10 to 20% by weight; SiO.sub.2, 43 to 58% by weight; TiO.sub.2, 0 to 3% by weight; ZrO.sub.2, 0 to 4% by weight, Sb.sub.2 O.sub.3, 0 to 2% by weight; F, 0 to 3% by weight in exchange for oxygen and up to 30% by weight of at least one inorganic pigment resistant to a burning-in temperature on the glass or the glass-ceramics; andwherein a sum total amount of the Li.sub.2 O, Na.sub.2 O and K.sub.2 O present is from 1 to 10% by weight;whereby an average bending tensile strength of a glass-ceramics article completely coated with said glass composition is greater than 30 MPa after burning or baking the glass composition into the glass-ceramics article.