US3887524A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of strengthening alumina ceramic by quenching with liquid medium
Assignee: Individual
•
Filing: 1972-12-20
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Granted: 1975-06-03
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Expires: 1992-12-20
Abstract
Abstract A method of strengthening a polycrystalline alumina ceramic. A body of alumina ceramic is refired to a temperature of from 1400*C to between 1700* and 1750*C for a time sufficient to heat the body to be strengthened throughout. The body is then quenched with a liquid medium which is at a temperature below about 250*C and which is a medium taken from the group consisting of oils having a viscosity as low as 1.4 centistokes, emulsions of oils in water with as little as 10% by weight of oil, triethanolamine, and mixtures of emulsifier and water. A strengthened body is produced which has improved flexural strength, tensile strength, impact resistance and thermal shock resistance.
Inventors
- 👤 Henry P Kirchner
- 👤 Ralph E Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:10
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/01; C04B35/10; C04B35/111
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
135 words
A METHOD OF STRENGTHENING A POLYCRYSTALLINE ALUMINA CERAMIC, COMPRISING THE STEPS OF REFIRING AN UNGLAZED BODY CONSISTING ESSENTIALLY OF ALUMINA CERAMIC HAVING A GRAIN SIZE UP TO 50UM TO A TEMPERATURE OF FROM 1400*C TO BETWEEN 1700* AND 1750*C FOR A TIME SUFFICIENT TO HEAT THE BODY TO BE STRENGTHENED THROUGHOUT, AND QUENCHING THE BODY WITH A LIQUID MEDIUM WHICH IS AT A TEMPERATURE BELOW ABOUT 250*C AND NO LOWER THAN ROOM TEMPERATURE AND WHICH IS A MEDIUM TAKEN FROM THE GROUP CONSISTING OF OILS HAVING A VISCOSITY AS LOW AS 1.4 CENTISTOKES, SAID OILS BEING MINERAL OIL, PETROLEUM OIL, VEGETABLE OIL, AND ANIMAL OIL AND EMULSIONS OF SUCH OILS IN WATER WITH AS LITTLE AS 10% BY WEIGHT OF OIL, WHEREBY THE FLEXURAL STRENGTH, TENSILE STRENGTH, IMPACT RESISTANCE AND THERMAL SHOCK RESISTANCE IS IMPROVED.
Claim 2
Independent Claim
135 words
A METHOD OF STRENGTHENING A POLYCRYSTALLINE ALUMINA CERAMIC, COMPRISING THE STEPS OF REFIRING AN UNGLAZED BODY CONSISTING ESSENTIALLY OF ALUMINA CERAMIC HAVING A GRAIN SIZE UP TO 50UM TO A TEMPERATURE OF FROM 1400*C TO BETWEEN 1700* AND 1750*C FOR A TIME SUFFICIENT TO HEAT THE BODY TO BE STRENGTHENED THROUGHOUT, AND QUENCHING THE BODY WITH A LIQUID MEDIUM WHICH IS AT A TEMPERATURE BELOW ABOUT 250*C AND NO LOWER THAN ROOM TEMPERATURE AND WHICH IS A MEDIUM TAKEN FROM THE GROUP CONSISTING OF OILS HAVING A VISCOSITY AS LOW AS 1.4 CENTISTOKES, SAID OILS BEING MINERAL OIL, PETROLEUM OIL, VEGETABLE OIL, AND ANIMAL OIL AND EMULSIONS OF SUCH OILS IN WATER WITH AS LITTLE AS 10% BY WEIGHT OF OIL, WHEREBY THE FLEXURAL STRENGTH, TENSILE STRENGTH, IMPACT RESISTANCE AND THERMAL SHOCK RESISTANCE IS IMPROVED.
Claim 3
Independent Claim
137 words
A method of strengthening a polycrystalline alumina ceramic, comprising the steps of refiring an unglazed body consisting essentially of alumina ceramic having a grain size up to 50 Mu m to a temperature of from 1400*C to between 1700* and 1750*C for a time sufficient to heat the body to be strengthened throughout, and quenching the body with a liquid medium which is at a temperature below about 250*C and no lower than room temperature and which is a medium taken from the group consisting of oils having a viscosity as low as 1.4 centistokes, said oils being mineral oil, petroleum oil, vegetable oil, and animal oil and emulsions of such oils in water with as little as 10% by weight of oil, whereby the flexural strength, tensile strength, impact resistance and thermal shock resistance is improved.
Claim 4
Independent Claim
137 words
A method of strengthening a polycrystalline alumina ceramic, comprising the steps of refiring an unglazed body consisting essentially of alumina ceramic having a grain size up to 50 Mu m to a temperature of from 1400*C to between 1700* and 1750*C for a time sufficient to heat the body to be strengthened throughout, and quenching the body with a liquid medium which is at a temperature below about 250*C and no lower than room temperature and which is a medium taken from the group consisting of oils having a viscosity as low as 1.4 centistokes, said oils being mineral oil, petroleum oil, vegetable oil, and animal oil and emulsions of such oils in water with as little as 10% by weight of oil, whereby the flexural strength, tensile strength, impact resistance and thermal shock resistance is improved.
Claim 5
Dependent Claim
14 words
A method as claimed in claim 1 in which the quenching medium is kerosene.
Claim 6
Dependent Claim
15 words
A method as claimed in claim 1 in which the quenching medium is fish oil.
Claim 7
Dependent Claim
26 words
A method as claimed in claim 1 in which the quenching medium is an emulsion of silicone oil having a viscosity of 100 centistokes and water.
Claim 8
Dependent Claim
37 words
A method as claimed in claim 1 in which the alumina ceramic is a ceramic material of 72% Al2O3 and 28%l Cr2O3, and the quenching medium is silicone oil having a viscosity of at least 100 centistokes.
Claim 9
Dependent Claim
36 words
A method as claimed in claim 1 in which the alumina ceramic has greater than 96% alumina, further comprising the step of, prior to the refiring step, polishing the body of ceramic for removing surface flaws.
Claim 10
Dependent Claim
36 words
A method as claimed in claim 6 in which the body has at least one sharp edge or corner, further comprising the step of rounding off the sharp edge or corner prior to the refiring step.
Claim 11
Dependent Claim
39 words
A method as claimed in claim 1 in which the body or alumina ceramic has at least one sharp edge or corner, further comprising the step of, prior to the refiring step, rounding off the sharp edge or corner.
Claim 12
Dependent Claim
23 words
A method as claimed in claim 1 in which the alumina ceramic is 96% alumina and the liquid medium is SAE30 motor oil.
Claim 13
Dependent Claim
30 words
A method as claimed in claim 1 in which the alumina is 96% alumina and the liquid medium is silicone oil having a viscosity of from 5 to 12,500 centistokes.
Claim 14
Dependent Claim
31 words
A method as claimed in claim 1 in which the alumina is 72% Al2O3 and 28 percent Cr2O3, and the liquid medium is silicone oil having a viscosity of 12,500 centistokes.
Claim 15
Dependent Claim
30 words
A method as claimed in claim 1 in which the alumina is 99.75% alumina, and the liquid medium is silicone oil having a viscosity of from 100 to 12,500 centistokes.
Claim 16
Independent Claim
156 words
A method of strengthening a polycrystalline alumina ceramic having a grain size up to 50 Mu m, comprising the steps of, where necessary to remove surface flaws where thermal shock failure can start, polishing an unglazed body consisting essentially of alumina ceramic to be strengthened, refiring the polished body to a temperature of from 1400*C to between 1700 and 1750*C for a time sufficient to heat the body to be strengthened throughout, and quenching the body with a liquid medium which is at a temperature below about 250*C and no lower than room temperature and which is a medium taken from the group consisting of oils having a viscosity as low as 1.4 centistokes, said oils being mineral oil, petroleum oil, vegetable oil, and animal oil, and emulsions of such oils in water with as little as 10% by weight of oil, whereby the flexural strength, tensile strength, impact resistance and thermal shock resistance is improved.
Claim 17
Independent Claim
156 words
A method of strengthening a polycrystalline alumina ceramic having a grain size up to 50 Mu m, comprising the steps of, where necessary to remove surface flaws where thermal shock failure can start, polishing an unglazed body consisting essentially of alumina ceramic to be strengthened, refiring the polished body to a temperature of from 1400*C to between 1700 and 1750*C for a time sufficient to heat the body to be strengthened throughout, and quenching the body with a liquid medium which is at a temperature below about 250*C and no lower than room temperature and which is a medium taken from the group consisting of oils having a viscosity as low as 1.4 centistokes, said oils being mineral oil, petroleum oil, vegetable oil, and animal oil, and emulsions of such oils in water with as little as 10% by weight of oil, whereby the flexural strength, tensile strength, impact resistance and thermal shock resistance is improved.
Claim 18
Dependent Claim
30 words
A method as claimed in claim 13 further comprising where the body has a sharp edge or corner, rounding off the sharp edge or corner prior to the refiring step.
Claim 19
Dependent Claim
37 words
A method as claimed in claim 13 in which the alumina is 72% Al2O3 and 28% Cr2O3, the body is polished prior to refiring, and the liquid medium is silicone oil having a viscosity of 100 centistokes.
Claim 20
Dependent Claim
39 words
A method as claimed in claim 13 in which the alumina is from 99.75 to 100% alumina, the body is polished prior to refiring, and the liquid medium is silicone oil having a viscosity as low as 5 centistokes.
Claim 21
Independent Claim
81 words
A method of strengthening a polycrystalline alumina ceramic, comprising the steps of refiring an unglazed body of alumina ceramic having a grain size up to 50 Mu m to a temperature of from 1400*C to between 1700 and 1750*C for a time sufficient to heat the body to be strengthened throughout, and quenching the body with triethanolamine at a temperature no higher than the boiling point thereof, whereby the flexural strength, tensile strength, impact resistance and thermal shock resistance is improved.
Claim 22
Independent Claim
81 words
A method of strengthening a polycrystalline alumina ceramic, comprising the steps of refiring an unglazed body of alumina ceramic having a grain size up to 50 Mu m to a temperature of from 1400*C to between 1700 and 1750*C for a time sufficient to heat the body to be strengthened throughout, and quenching the body with triethanolamine at a temperature no higher than the boiling point thereof, whereby the flexural strength, tensile strength, impact resistance and thermal shock resistance is improved.
References Cited (Backward Citations)
US3712830A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |