Abstract The instant invention is directed to the production of highly crystalline glass-ceramic articles demonstrating high intrinsic mechanical strength and toughness containing crystals of canasite and/or agrellite and/or fedorite as the predominant crystal phase. The articles have overall compositions consisting essentially, expressed in terms of weight percent on the oxide basis, of about ______________________________________ SiO 2 45-75
CaO 8-30
F 3.5-12
Na 2 O 3-15
K 2 O 0-20
Na 2 O + K 2 O
5-25
B 2 O 3 0-6
Al 2 O 3 0-7
ZrO 2 0-12.
______________________________________
Inventors
👤 George H. Beall
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-23 20:11
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/16
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
87 words
A method for preparing a highly crystalline glass-ceramic article exhibiting high toughness and a modulus of rupture in excess of 20,000 psi, wherein the predominant crystal phase is canasite and/or agrellite and/or fedorite, which comprises the following steps: (a) melting a batch for a glass consisting essentially, expressed in terms of weight percent on the oxide basis, of about ______________________________________
SiO.sub.2 45-75
CaO 8-30
F 3.5-12
Na.sub.2 O 3-15
K.sub.2 O 0-20
Na.sub.2 O + K.sub.2 O
5-25
B.sub.2 O.sub.3
0-6
Al.sub.2 O.sub.3
0-7
ZrO.sub.2 0-12
______________________________________
Claim 2
Independent Claim
87 words
A method for preparing a highly crystalline glass-ceramic article exhibiting high toughness and a modulus of rupture in excess of 20,000 psi, wherein the predominant crystal phase is canasite and/or agrellite and/or fedorite, which comprises the following steps: (a) melting a batch for a glass consisting essentially, expressed in terms of weight percent on the oxide basis, of about ______________________________________
SiO.sub.2 45-75
CaO 8-30
F 3.5-12
Na.sub.2 O 3-15
K.sub.2 O 0-20
Na.sub.2 O + K.sub.2 O
5-25
B.sub.2 O.sub.3
0-6
Al.sub.2 O.sub.3
0-7
ZrO.sub.2 0-12
______________________________________
Claim 3
Dependent Claim
51 words
(b) simultaneously cooling the melt to a temperature at least below the transformation range thereof and shaping a glass article of a desired configuration therefrom; and (c) exposing said glass article to a temperature between about 500°-1000° C. for a time sufficient to cause the growth therein of the desired crystals.
Claim 4
Dependent Claim
51 words
(b) simultaneously cooling the melt to a temperature at least below the transformation range thereof and shaping a glass article of a desired configuration therefrom; and (c) exposing said glass article to a temperature between about 500°-1000° C. for a time sufficient to cause the growth therein of the desired crystals.
Claim 5
Dependent Claim
41 words
A method according to claim 1 wherein said glass consists essentially of about ______________________________________
SiO.sub.2
50-65
CaO 15-24
F 5-9
Na.sub.2 O
3-13
K.sub.2 O
3-15
Na.sub.2 O + K.sub.2 O
11-22
B.sub.2 O.sub.3
0-3
Al.sub.2 O.sub.3
0-3
ZrO.sub.2
0-8.
______________________________________
Claim 6
Dependent Claim
47 words
A method according to claim 1 wherein said glass article is exposed to a temperature between about 500°-750° C. for about 0.5-6 hours to develop nucleation and then to a temperature between about 800°-1000° C. for about 0.5-8 hours to cause the growth of the desired crystals.