Glass ceramic substrate made of a transparent, colored LAS glass ceramic and method for producing it

Patent metadata

Field	Value
Publication number	US-2016176752-A1
Application number	US-201514757392-A
Country	US
Kind code	A1
Filing date	Dec 23, 2015
Priority date	Dec 23, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A glass ceramic substrate made of a transparent, colored LAS glass ceramic is provided. The glass ceramic has a gradient layer with keatite solid solution and an underlying core with high-quartz solid solution as predominant crystal phase. The keatite solid solution in a depth of 10 μm or greater exceeds 50% of the sum of the high-quartz solid solution proportion and keatite solid solution proportion. The ceramization includes a crystal transformation step, in which the high-quartz solid solution is transformed at a maximum temperature in the range of 910° to 980° and a time period of between 1 and 25 minutes in part into the keatite solid solution.

First claim

What is claimed is:

1 . A glass ceramic substrate made of a transparent, colored LAS glass ceramic comprising a composition (in wt %):

Al 2 O 3
18-23,

Li 2 O
3.0-4.2,

SiO 2
60-69,

ZnO
0-2,

Na 2 O + K 2 O
0.2-1.5,

MgO
  0-1.5,

CaO + SrO + BaO
0-4,

B 2 O 3
0-2,

TiO 2
2.3-4,  

ZrO 2
0.5-2,  

P 2 O 5
0-3,

SnO 2
     0-<0.6,

Sb 2 O 3
  0-1.5,

As 2 O 3
  0-1.5,

TiO 2 + ZrO 2 + SnO 2
3.8-6,  

V 2 O 5
      0.01-0.06, and

Fe 2 O 3
0.03-0.2, 

wherein the LAS glass ceramic has a gradient layer and an underlying core, and
wherein the LAS glass ceramic has keatite solid solution (KSS) as a predominant crystal phase in the underlying core and has high-quartz solid solution (HQSS) as a predominant crystal phase in the gradient layer, and
wherein the KSS crystal phase has a proportion in any depth ≧20 μm that exceeds 50% of a sum of the HQSS and KSS crystal phase proportions.

2 . The glass ceramic substrate according to claim 1 , further comprising coloring oxides in sum total to a maximum of 1.0 wt %

3 . The glass ceramic substrate according to claim 1 , wherein the LAS glass ceramic has a fracture strength, expressed in a CIL value, of at least 0.8 N in the case of an ambient humidity of 10% and/or a CIL value of at least 0.98 N in the case of an ambient humidity of 1%.

4 . A glass ceramic substrate made of a transparent, colored LAS glass ceramic comprising a composition (in wt %):

Al 2 O 3
18-23,

Li 2 O
3.0-4.2,

SiO 2
60-69,

ZnO
0-2,

Na 2 O + K 2 O
0.2-1.5,

MgO
  0-1.5,

CaO + SrO + BaO
0-4,

B 2 O 3
0-2,

TiO 2
2.5-4,  

ZrO 2
0.5-2,  

P 2 O 5
0-3,

SnO 2
     0-<0.6,

Sb 2 O 3
  0-1.5,

As 2 O 3
  0-1.5,

TiO 2 + ZrO 2 + SnO 2
3.8-6,  

V 2 O 5
      0.01-0.06, and

Fe 2 O 3
0.03-0.2, 

wherein the LAS glass ceramic has a gradient layer and an underlying core,
wherein the LAS glass ceramic has keatite solid solution (KSS) as a predominant crystal phase in the underlying core and has high-quartz solid solution (HQSS) as a predominant crystal phase in the gradient layer, and
wherein the LAS glass ceramic has a strength, expressed in a CIL value, of at least 0.8 N at an ambient humidity of 10% and/or a CIL value of at least 0.98 N at an ambient humidity of 1%.

5 . The glass ceramic substrate according to claim 4 , further comprising coloring oxides in sum total to a maximum of 1.0 wt %.

6 . The glass ceramic substrate according to claim 4 , further comprising a depth profile of the HQSS and KSS crystal phase proportions and/or a strength is achieved by phase transformation of HQSS crystals to KSS crystals during ceramization with a maximum temperature T max and over a residence time t(T max ) of this maximum temperature in a temperature-time region that is delimited by four straight lines, which connect the four corner points with the value pairs (T max =910° C.; t(T max )=25 minutes), (T max =960° C.; t(T max )=1 minute), (T max =980° C.; t(T max )=1 minute), and (T max =965° C.; t(T max )=25 minutes).

7 . The glass ceramic substrate according to claim 4 , wherein the LAS glass ceramic has a maximum scattered proportion, standardized to a glass ceramic with a thickness of 4 mm, is at most 15% at a wavelength of 470 nm.

8 . The glass ceramic substrate according to claim 7 , wherein the maximum scattered proportion does not exceed 20% in a wavelength range from 400 nm to 500 nm.

9 . The glass ceramic substrate according to claim 4 , wherein the LAS glass ceramic is free of arsenic and antimony, apart from unavoidable traces, and contains at least 0.1 wt % SnO 2 .

10 . The glass ceramic substrate according to claim 4 , wherein the composition meets a condition 1<Fe 2 O 3 /V 2

Assignees

• Schott Ag

Inventors

• Gabel Falk
• Hochrein Oliver
• Weiss Evelin
• Dudek Roland
• Martens Uwe

Classifications

• C03B32/02

  Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles {(C03B27/012 takes precedence)} · CPC title

• C03C10/0027 Primary

  containing SiO2, Al2O3, Li2O as main constituents · CPC title

• C03C3/097

  containing phosphorus, niobium or tantalum · CPC title

• C03C23/007

  by thermal treatment · CPC title

• C03C4/02

  for coloured glass · CPC title