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US4187115A Expired / Lapsed US ⏱️ 0.0 years remaining

Anorthite glass-ceramics

Assignee: Corning Glass Works
•
Filing: 1978-09-01
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Granted: 1980-02-05
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Expires: 1998-09-01
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Abstract

Abstract The instant invention is related to the production of highly refractory glass-ceramic articles having moderate coefficients of thermal expansion in the CaO-Al 2 O 3 -SiO 2 -TiO 2 field wherein anorthite comprises the predominant crystal phase with a minor amount of rutile also being present. The articles demonstrate very high D.C. volume resistivities and high dielectric constants with exceptionally low loss tangents and dielectric loss factors. Their refractoriness and moderate expansion suggests an application such as kiln furniture where high temperatures, but not severe temperature changes, are encountered. Their high D.C. resistivities and low A.C. dielectric losses suggest their utility as insulators and electronic substrate materials.

Inventors

  • 👤 Richard F. Reade

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-25 21:56
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/02; H01B3/08; H01B3/087; C; C03; C03C; C03C10/00; C03C10/0036

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 131 words
A glass-ceramic article exhibiting a Log ρ at 250° C. of about 10-16, a Log ρ at 350° C. of about 9-13, a dielectric constant at 10 5 Hz of about 10-13, a dielectric constant at 10 6 Hz of about 9-13, and a coefficient of thermal expansion over the range 20°-300° C. of about 35-65×10 -7 /°C. consisting essentially of a fine-grained crystal phase uniformly dispersed within a glassy matrix and constituting greater than 50% by volume of the article, said crystal phase consisting essentially of triclinic anorthite and rutile and being formed through crystallization in situ from a glass body consisting essentially, expressed in weight percent on the oxide basis, of about 10-18% CaO, 29-35% Al 2 O 3 , 30-39% SiO 2 , and 13-20% TiO 2 .
Claim 2
Dependent Claim 131 words
A glass-ceramic article exhibiting a Log ρ at 250° C. of about 10-16, a Log ρ at 350° C. of about 9-13, a dielectric constant at 10 5 Hz of about 10-13, a dielectric constant at 10 6 Hz of about 9-13, and a coefficient of thermal expansion over the range 20°-300° C. of about 35-65×10 -7 /°C. consisting essentially of a fine-grained crystal phase uniformly dispersed within a glassy matrix and constituting greater than 50% by volume of the article, said crystal phase consisting essentially of triclinic anorthite and rutile and being formed through crystallization in situ from a glass body consisting essentially, expressed in weight percent on the oxide basis, of about 10-18% CaO, 29-35% Al 2 O 3 , 30-39% SiO 2 , and 13-20% TiO 2 .
Claim 3
Dependent Claim 20 words
A glass-ceramic article according to claim 1 wherein the mole ratio Al 2 O 3 :CaO ranges between about 0.9-1.6.
Claim 4
Dependent Claim 25 words
A glass-ceramic article according to claim 2 wherein the mole ratio Al 2 O 3 :CaO is greater than 1 but no greater than 1.1.
Claim 5
Dependent Claim 56 words
A glass-ceramic article according to claim 1 wherein said glass body also contains up to 3% MgO, up to 10% SrO, up to 5% BaO, up to 7% PbO, up to 5% CdO, up to 6% P 2 O 5 , and up to 1.5% F, the total of all such components not exceeding about 10%.

References Cited (Backward Citations)

US2920971A Cited
US3677728A Cited
US3772041A Cited
US3950174A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1983-02-04 1983-08-06 1984-02-05 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1987-02-04 1987-08-06 1988-02-05 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1991-02-04 1991-08-06 1992-02-05 $7700.00 Window Closed / Lapsed

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