US3901716A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Micro-crystalline material and method of preparation
Assignee: National Research Development Corp UK
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Filing: 1974-01-22
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Granted: 1975-08-26
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Expires: 1994-01-22
Abstract
Abstract The invention relates to a method of making a refractory microcrystalline material by devitrification of a melt of a base glass composition containing Al2O3, SiO2 and, optionally, CaO and MgO, and as additives to the base glass composition, iron oxide and chromium oxide, wherein devitrification is carried out by cooling the melt without re-heating the melt at any stage; and to a refractory micro-crystalline material.
Inventors
- 👤 Philip Sydney Rogers
- 👤 James Williamson
- 👤 Peter Edwin Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:26
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0063; C03C10/0036; C03C10/0045
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
11 words
A METHOD OF MAKING A MICRO-CRYSTALLINE MATERIAL COMPRISING THE STEPS OF
Claim 2
Independent Claim
11 words
A METHOD OF MAKING A MICRO-CRYSTALLINE MATERIAL COMPRISING THE STEPS OF
Claim 3
Dependent Claim
88 words
PREPARING A MELT OF A COMPOSITION COMPRISING A BASE GLASS COMPOSITION CONSISTING OF FROM 0 TO 30 WEIGHT PERCENT MGO, FROM 5 TO 35 WEIGHT PERCENT AL2O3, FROM 35 TO 75 WEIGHT PERCENT SIO2, AND FROM 0 TO 30 WEIGHT PERCENT CAO, FROM 0.5 TO 3 PARTS BY WEIGHT CHROMIUM OXIDE (EXPRESSED AS CR2O3) PER 100 PARTS BY WEIGHT OF THE BASE GLASS COMPOSITION AND FROM 0.5 TO 10 PARTS BY WEIGHT IRON OXIDE (EXPRESSED AS FE2O3) PER 100 PARTS BY WEIGHT OF THE BASE GLASS COMPOSITION, AND
Claim 4
Dependent Claim
88 words
PREPARING A MELT OF A COMPOSITION COMPRISING A BASE GLASS COMPOSITION CONSISTING OF FROM 0 TO 30 WEIGHT PERCENT MGO, FROM 5 TO 35 WEIGHT PERCENT AL2O3, FROM 35 TO 75 WEIGHT PERCENT SIO2, AND FROM 0 TO 30 WEIGHT PERCENT CAO, FROM 0.5 TO 3 PARTS BY WEIGHT CHROMIUM OXIDE (EXPRESSED AS CR2O3) PER 100 PARTS BY WEIGHT OF THE BASE GLASS COMPOSITION AND FROM 0.5 TO 10 PARTS BY WEIGHT IRON OXIDE (EXPRESSED AS FE2O3) PER 100 PARTS BY WEIGHT OF THE BASE GLASS COMPOSITION, AND
Claim 5
Dependent Claim
41 words
COOLING THE MELT AT SUCH A RATE THAT INITIALLY CRYSTALS OF SPINEL, MOSTLY LESS THAN 1 UM IN SIZE, ARE FORMED WITHIN THE MELT AND SUBSEQUENTLY CRYSTALS OF A SILICATE PHASE GROW UPON THE SPINEL CRYSTALS TO YIELD THE MICRO-CRYSTALLINE MATERIAL.
Claim 6
Dependent Claim
41 words
COOLING THE MELT AT SUCH A RATE THAT INITIALLY CRYSTALS OF SPINEL, MOSTLY LESS THAN 1 UM IN SIZE, ARE FORMED WITHIN THE MELT AND SUBSEQUENTLY CRYSTALS OF A SILICATE PHASE GROW UPON THE SPINEL CRYSTALS TO YIELD THE MICRO-CRYSTALLINE MATERIAL.
Claim 7
Dependent Claim
42 words
cooling the melt at such a rate that initially crystals of spinel, mostly less than 1 Mu m in size, are formed within the melt and subsequently crystals of a silicate phase grow upon the spinel crystals to yield the micro-crystalline material.
Claim 8
Dependent Claim
42 words
cooling the melt at such a rate that initially crystals of spinel, mostly less than 1 Mu m in size, are formed within the melt and subsequently crystals of a silicate phase grow upon the spinel crystals to yield the micro-crystalline material.
Claim 9
Dependent Claim
22 words
A method according to claim 1 wherein the base glass composition contains greater than 8.5 to less than 30 weight percent CaO.
Claim 10
Dependent Claim
19 words
A method according to claim 1 wherein the base glass composition contains from 5 to 30 weight percent MgO.
Claim 11
Dependent Claim
41 words
A method according to claim 1 wherein the composition contains from 0.5 to 5 parts by weight iron oxide (expressed as Fe2O3) per 100 parts by weight of the base glass composition and the melt is prepared in an oxidising atmosphere.
Claim 12
Dependent Claim
32 words
A method according to claim 1 wherein on cooling the temperature of the composition is held constant for up to 3 hours at a temperature between the temperature of melting and 800*C.
Claim 13
Dependent Claim
23 words
A method according to claim 5 wherein the temperature of the composition is held constant at a temperature of from 800* to 1100*C.
Claim 14
Dependent Claim
55 words
A method according to claim 1 wherein said melt is prepared in an oxidizing atmosphere and wherein said cooling step comprises first cooling the melt to a temperature of from 900* to 1000*C and holding the composition at this temperature for from 3/4 to 1 1/2 hours, and subsequently cooling the composition to ambient temperature.
Claim 15
Dependent Claim
94 words
A COMPOSITION USABLE FOR PREPARING A MICROCRYSTALLINE MATERIAL IN ACCORDANCE WITH THE METHOD OF CLAIM 1 COMPRISING FROM 0 TO 30 WEIGHT PERCENT MGO, FROM 5 TO 35 WEIGHT PERCENT A12O3, FROM 35 TO 75 WEIGHT PERCENT SIO2, FROM 0 TO 30 WEIGHT PERCENT CAO, FROM O.5 TO 3 PARTS BY WEIGHT CHROMIUM OXIDE (EXPRESSES AS CR2O3) PER 100 PARTS BY WEIGHT OF THE COMBINED MGO, A12O3, SIO, AND FROM 0.5 TO 10 PARTS BY WEIGHT IRON OXIDE (EXPRESSED AS FE2O3) PER 100 PARTS BY WEIGHT OF THE COMBINED MGO, A12O3, SIO2 AND CAO.
Claim 16
Dependent Claim
18 words
A composition according to claim 8 comprising from greater than 8.5 to less than 30 weight percent CaO.
Claim 17
Dependent Claim
14 words
A composition according to claim 8 comprising from 5 to 30 weight percent MgO.
Claim 18
Dependent Claim
30 words
A composition according to claim 8 comprising 0.5 to 5 parts by weight iron oxide (expressed as Fe2O3) per 100 parts by weight of combined MgO, Al2O3, SiO2 and CaO.
Claim 19
Dependent Claim
34 words
A micro-crystalline material comprising crystals of spinel less than 1 Mu m in size and crystals of silicate phase grown on said spinel crystals, said material being made by the method of claim 1.
Claim 20
Dependent Claim
34 words
A micro-crystalline material comprising crystals of spinel less than 1 Mu m in size and crystals of silicate phase grown on said spinel crystals, said material being made by the method of claim 2.
Claim 21
Dependent Claim
34 words
A micro-crystalline material comprising crystals of spinel less than 1 Mu m in size and crystals of silicate phase grown on said spinel crystals, said material being made by the method of claim 3.
Claim 22
Dependent Claim
34 words
A micro-crystalline material comprising crystals of spinel less than 1 Mu m in size and crystals of silicate phase grown on said spinel crystals, said material being made by the method of claim 4.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |