Glass-ceramic of lithium aluminosilicate type containing a solid solution of b-spodumene

Patent metadata

Field	Value
Publication number	US-2016009591-A1
Application number	US-201414770233-A
Country	US
Kind code	A1
Filing date	Feb 28, 2014
Priority date	Feb 28, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

A glass-ceramic of the lithium aluminosilicate type includes a solid solution of β-spodumene and exhibits, for a thickness of 4 mm; a light transmittance within a range extending from 0.3 to 2%, an optical transmittance for a wavelength of 625 nm of greater than 3.0%, an optical transmittance for a wavelength of 950 nm within a range extending from 50 to 75%, an optical transmittance for a wavelength of 1600 nm of at least 50%, and L*, a*, b* colorimetric coordinates in diffuse reflection for an illuminant D65 and a reference observer at 2° such that 15.0≦L*≦40.0, −3.0≦a*≦3.0 and −10.0≦b*≦3.0. The chemical composition of the glass-ceramic includes the following constituents, varying within the limits by weight defined: SnO 2 0.2-0.6%, V 2 O 5 0.015-0.070%, Cr 2 O 3 0.01-0.04% or Bi 2 O 3 0.05-3.0%, Fe 2 O 3 0.05-<0.15%, AS 2 O 3 +Sb 2 O 3 <0.1 %.

First claim

1 . A glass-ceramic of the lithium aluminosilicate type comprising a solid solution of β-spodumene and exhibiting, for a thickness of 4 mm;
a light transmittance within a range extending from 0.3 to 2%,
an optical transmittance for a wavelength of 625 nm of greater than 2.0%,
an optical transmittance for a wavelength of 950 nm within a range extending from 50 to 75%,
an optical transmittance for a wavelength of 1600 nm of at least 50%, and
L*, a*, b* colorimetric coordinates in diffuse reflection for an illuminant D65 and a reference observer at 2° such that 15.0≦L*≦40.0, −3.0≦a*≦3.0 and −10.0≦b*≦3.0,
said glass-ceramic being such that its chemical composition comprises the following constituents, varying within the limits by weight defined below:
SnO 2 0.2-0.6%,
V 2 O 5 0.015-0.070%,
Cr 2 O 3 0.01-0.04% or Bi 2 O 3 0.05-3.0%
Fe 2 O 3 0.05-<0.15%
As 2 O 3 +Sb 2 O 3 <0.1%.

2 . The glass-ceramic according to claim 1 , wherein the content of V 2 O 5 is at most 0.060%.

3 . The glass-ceramic according to claim 1 , comprising a solid solution of β-spodumene as main crystal phase.

4 . The glass-ceramic according to claim 1 , preceding claims, wherein the content by weight of SnO 2 is at most 0.4%.

5 . The glass-ceramic according to claim 1 , wherein the content by weight of Fe 2 O 3 is at least 0.07% and at most 0.12%.

6 . The glass-ceramic according to claim 1 , wherein the content by weight of Bi 2 O 3 is at least 0.1% and at most 1.5%.

7 . The glass-ceramic according to claim 1 , wherein the content by weight of Cr 2 O 3 is at least 0.02% and at most 0.035%.

8 . The glass-ceramic according to claim 1 , the chemical composition of which comprises less than 200 ppm of cobalt oxide.

9 . The glass-ceramic according to claim 1 , the chemical composition of which comprises the following constituents, varying within the limits by weight defined below:
SiO 2 60-72% Al 2 O 3 18-23% Li 2 O 2.5-4.5% MgO 0-3% ZnO 1-3% TiO 2 1.5-4% ZrO 2 0-2.5% BaO 0-5% SrO 0-5% With BaO+SrO 0-5% CaO 0-2% Na 2 O 0-1.5% K 2 O 0-1.5% P 2 O 5 0-5% B 2 O 3 0-2%

10 . The glass-ceramic according to claim 9 , wherein the sum of the contents of SiO 2 , Al 2 O 3 , Li 2 O, MgO, ZnO, TiO 2 , ZrO 2 , BaO, SrO, CaO, Na 2 O, Li 2 O, K 2 O, P 2 O 5 , B 2 O 3 , SnO 2 , V 2 O 5 , Fe 2 O 3 , Cr 2 O 3 and Bi 2 O 3 is at least 98%.

11 . An article comprising a glass-ceramic as claimed in claim 1 .

12 . A lithium aluminosilicate glass, precursor of a glass-ceramic, a chemical composition of which corresponds to that of a glass-ceramic as claimed in claim 1 .

13 . A process for the preparation of a glass-ceramic, comprising carrying out a heat treatment of a charge of vitrifiable starting materials under conditions which successively provide for the melting, refining and then ceramization, wherein said charge exhibits a composition which makes it possible to obtain the glass-ceramic as claimed in claim 1 .

14 . The glass-ceramic according to claim 1 , wherein
the light transmittance is within a range extending from 0.6 to 1.7%, the optical transmittance for a wavelength of 625 nm is greater than 3.0%, SnO 2 0.25-0.5% V 2 O 5 0.015-0.050% As 2 O 3 +Sb 2 O 3 <0.05%.

15 . The glass-ceramic according to claim 8 , wherein the chemical composition comprises less than 100 ppm of cobalt oxide.

16 . The glass-ceramic according to claim 10 , wherein the sum of the contents of SiO 2 , Al 2 O 3 , Li 2 O, MgO, ZnO, TiO 2 , ZrO 2 , BaO, SrO, CaO, Na 2 O, Li 2 O, K 2 O, P 2 O 5 , B 2 O 3 , SnO 2 , V 2 O 5 , Fe 2 O 3 , Cr 2 O 3 and Bi 2 O 3 is at least 99%.

17 . The article according to claim 11 , wherein the article is a cooktop.

Assignees

• Eurokera

Inventors

• Plevacova Kamila
• Jousseaume Cécile
• Vilato Pablo
• Lecomte Emmanuel

Classifications

• C03C2204/00

  Glasses, glazes or enamels with special properties · CPC title

• C03C4/02

  for coloured glass · CPC title

• H05B3/74

  Non-metallic plates {, e.g. vitroceramic, ceramic or glassceramic hobs, also including power or control circuits} · CPC title

• C03C3/085

  containing an oxide of a divalent metal · CPC title

• C03C3/087

  containing calcium oxide, e.g. common sheet or container glass · CPC title