JPWO2020094734A5 - - Google Patents

Claims (10)

A transparent glass-ceramic of the lithium aluminosilicate type containing a solid solution of β-quartz as the main crystal phase, the composition of which, expressed in percent by weight of oxides, is:
- 63% to 67.5% _SiO2 ,
- 18% to 21% _{Al2O3 ,}
- ₂ % to 2.9% Li2O,
- 0 to 1.5% MgO;
1% to 3.2% ZnO,
- 0 to 4% BaO;
- 0 to 4% SrO;
- 0 to 2% CaO,
- 2% to 5% _TiO2 ,
- 0 to ₃ % ZrO2,
- 0 to 1% _Na2O ,
- 0 to ₁ % K2O;
- 0 to ₅ % _P2O5 , and
(0.74MgO+0.19BaO+0.29SrO ₊ 0.53CaO+0.48Na2O _{+ 0.32K2O} )/Li2O<0.9 ,
glass-ceramics , including _2. The glass-ceramic of claim 1, wherein the composition comprises Li2O with a content of 2.85% or less and ZnO from 1% to 3%. Glass-ceramic according to claim 1 or ₂ , wherein the composition comprises at least _0.5 % P2O5. Glass-ceramic according to claim 1 or ₂ , wherein the composition does not contain any P2O5 except for unavoidable traces and contains 1% to _2.5 % ZnO. the composition does not contain any _{B2O3 ,} except for unavoidable trace amounts,
said composition being free of As ₂ O ₃ and Sb ₂ O ₃ except for unavoidable traces and containing SnO ₂ as said at least one refining agent;
_The composition contains _V2O5 as a colorant, either alone or mixed with at _least one other colorant selected from CoO, _{Cr2O3 ,} and _Fe2O3 . 5. The glass-ceramic according to any one of items 1 to 4. Glass-ceramic according to any one of claims 1 to 5, having a coefficient of thermal expansion: CTE _(25-450°C) in the range ±14×10 ^-7 /K. A cooking stove top made from the glass-ceramic according to any one of claims 1 to 6. Lithium aluminosilicate glass, a precursor of the glass-ceramic of any one of claims 1-6, having a composition that makes it possible to obtain the glass-ceramic of any one of claims 1-6. , a lithium aluminosilicate glass having a liquidus temperature below 1400°C and a viscosity at a liquidus temperature above 400 Pa·s. A method of preparing a stove top according to claim 7, comprising:
- melting a vitrified charge of raw materials and then fining the resulting molten glass;
- cooling the resulting fined molten glass while simultaneously forming the glass into the desired shape on the top of a stove; and - subjecting the formed glass to a ceramizing heat treatment.
having in succession
7. A method, wherein the vitrifiable charge of raw materials has a composition that makes it possible to obtain a glass-ceramic according to any one of claims 1-6. 10. Process according to claim 9, wherein the raw material _vitrifiable charge _, which is free of _As2O3 and _Sb2O3 except for unavoidable traces _, contains SnO2 as a fining agent.