US4047960A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refractory partially crystalline materials with good visible transparency
Assignee: Corning Glass Works
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Filing: 1976-06-18
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Granted: 1977-09-13
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Expires: 1996-06-18
Abstract
Abstract This invention is concerned with the manufacture of refractory articles of a partially crystalline nature, i.e., materials having a substantial crystal content within a glassy matrix, but wherein the crystal phase normally comprises less than about 50% by volume of the materials. The bodies are produced through the heat treatment of glass articles having compositions within the Al 2 O 3 --SiO 2 --TiO 2 --Nb 2 O 5 and/or Ta 2 O 5 system at elevated temperatures, but not in excess of about 1150° C., to cause the in situ growth of crystals. The materials, containing aluminum niobate, aluminum tantalate, or an aluminum niobate-tantalate solid solution as the predominant crystal phase, exhibit a high degree of transparency to visible light, and retain that transparency even after very extended exposures to temperatures up to in excess of 1000° C. That capability has recommended their utility as arc-tubes or as envelopes for high temperature lamps.
Inventors
- 👤 Richard F. Reade
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:31
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0009
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
226 words
A method for making a transparent partially crystalline article containing at least about 20%, but less than about 50%, by volume crystals dispersed within a residual glassy matrix wherein the predomininant crystal phase consists essentially of aluminum niobate, aluminum tantalate, or an aluminum-tantalate solid solution having a crystal size of about 300-500A in diameter, which crystalline article retains its transparency after extended exposures to temperatures up to about 1150° C., comprising the steps of: a. melting a batch for a glass consisting essentially, in weight percent on the oxide basis, of about 10-20% Al 2 O 3 , 59-72% SiO 2 , 5-8% TiO 2 , and 5-20% Nb 2 O 5 and/or Ta 2 O 5 0 to about 2% K 2 O and/or 0 to about 6% Cs 2 O; b. simultaneously cooling said melt to a temperature at least within the transformation range and shaping a glass article of a desired configuration therefrom; c. heating said glass article to a temperature of at least about 1000° c., but not more than about 1150° C., for a period of time sufficient to cause the crystallization of aluminum niobate, aluminum tantalate, and/or an aluminum niobate-tantalate solid solution having a crystal size of about 300-500A to occur in situ to produce a transparent partially crystalline article; and then d. cooling said crystallized article to room temperature.
Claim 2
Independent Claim
226 words
A method for making a transparent partially crystalline article containing at least about 20%, but less than about 50%, by volume crystals dispersed within a residual glassy matrix wherein the predomininant crystal phase consists essentially of aluminum niobate, aluminum tantalate, or an aluminum-tantalate solid solution having a crystal size of about 300-500A in diameter, which crystalline article retains its transparency after extended exposures to temperatures up to about 1150° C., comprising the steps of: a. melting a batch for a glass consisting essentially, in weight percent on the oxide basis, of about 10-20% Al 2 O 3 , 59-72% SiO 2 , 5-8% TiO 2 , and 5-20% Nb 2 O 5 and/or Ta 2 O 5 0 to about 2% K 2 O and/or 0 to about 6% Cs 2 O; b. simultaneously cooling said melt to a temperature at least within the transformation range and shaping a glass article of a desired configuration therefrom; c. heating said glass article to a temperature of at least about 1000° c., but not more than about 1150° C., for a period of time sufficient to cause the crystallization of aluminum niobate, aluminum tantalate, and/or an aluminum niobate-tantalate solid solution having a crystal size of about 300-500A to occur in situ to produce a transparent partially crystalline article; and then d. cooling said crystallized article to room temperature.
Claim 3
Dependent Claim
40 words
A method according to claim 1 wherein said glass article is first heated to about 800°-1000° C. for a period of time sufficient to effect substantial nucleation within said glass prior to heating to crystallize the glass article in situ.
Claim 4
Dependent Claim
11 words
A transparent partially crystalline article made in accordance with claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-12 | 1981-03-14 | 1981-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-12 | 1985-03-14 | 1985-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-12 | 1989-03-14 | 1989-09-13 | $7700.00 | Window Closed / Lapsed |