US4306909A
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Low-expansion ceramics and method of producing the same
Assignee: NGK Insulators Ltd
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Filing: 1980-05-22
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Granted: 1981-12-22
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Expires: 2000-05-22
Abstract
Abstract The present invention relates to low-expansion ceramics essentially consisting of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ), that major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-iron oxide, and that the ceramics has a coefficient of thermal expansion of not more than 20×10 -7 (1/° C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure 1,100° C. for 1,000 hours, and a method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide, and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ); plasticizing the batch if necessary and shaping the batch; drying the body thus formed and firing the formed body at 1,300° C. to 1,700° C. for 0.5 to 48 hours, thereby having a coefficient of thermal expansion of less than 20×10 -7 (1/° C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure at 1,100° C. for 1,000 hours, wherein the shape of ceramics is a honeycomb structure.
Inventors
- 👤 Isao Oda
- 👤 Tadaaki Matsuhisa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:16
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/478
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
129 words
Low-expansion ceramics essentially consisting of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ), that the major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-iron oxide, and that the ceramics have a coefficient of thermal expansion of not more than 20×10 -7 (1/°C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure at 1,100° C. for 1,000 hours.
Claim 2
Dependent Claim
129 words
Low-expansion ceramics essentially consisting of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ), that the major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-iron oxide, and that the ceramics have a coefficient of thermal expansion of not more than 20×10 -7 (1/°C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure at 1,100° C. for 1,000 hours.
Claim 3
Dependent Claim
69 words
Low-expansion ceramics as defined in claim 1, wherein the chemical composition of the ceramics consists of 2.5 to 17% by weight of magnesia (MgO), 13.5 to 62% by weight of alumina (Al 2 O 3 ), 31.5 to 75% by weight of titanium in terms of titanium oxide (TiO 2 ), and 2 to 10% by weight of iron in terms of ferric oxide (Fe 2 O 3 ).
Claim 4
Dependent Claim
16 words
Low-expansion ceramics as defined in claim 1, wherein the shape of ceramics is a honeycomb structure.
Claim 5
Independent Claim
154 words
A method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ); plasticizing the batch if necessary and shaping the batch; drying the body thus formed; and firing the formed body at 1,300° C. to 1,700° C. for 0.5 to 48 hours, thereby having a coefficient of thermal expansion of less than 20×10 -7 (1/°C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure at 1,100° C. for 1,000 hours.
Claim 6
Independent Claim
154 words
A method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ); plasticizing the batch if necessary and shaping the batch; drying the body thus formed; and firing the formed body at 1,300° C. to 1,700° C. for 0.5 to 48 hours, thereby having a coefficient of thermal expansion of less than 20×10 -7 (1/°C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure at 1,100° C. for 1,000 hours.
Claim 7
Dependent Claim
70 words
A method of producing low-expansion ceramics as defined in claim 4, wherein said chemical composition consists of 2.5 to 17% by weight of magnesia (MgO), 13.5 to 62% by weight of alumina (Al 2 O 3 ), 31.5 to 75% by weight of titanium in terms of titanium oxide (TiO 2 ), and 2 to 10% by weight of iron in terms of ferric oxide (Fe 2 O 3 ).
Claim 8
Dependent Claim
119 words
A method of producing low-expansion ceramics as defined in claim 4, wherein said compounds so selected as to provide the chemical composition of 1.5 to 20% by weight of magnesia (MgO), 6 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ) are in a mixture of materials selected from the group consisting of magnesia, magnesium carbonate, magnesium hydroxide, alumina, aluminum hydroxide, anatase type titanium dioxide, rutile type titanium dioxide, metallic iron, α type ferric oxide, γ type ferric oxide, hydrous iron oxide, and ilmenite.
Claim 9
Dependent Claim
179 words
Low-expansion ceramics having a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-iron oxide as the major component of crystalline phase and that the ceramics have a coefficient of thermal expansion of not more than 20×10 -7 (1/°C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure 1,100° C. for 1,000 hours, said low-expansion ceramics being made by the process comprising the steps of preparing a batch of compounds so as to provide a chemical composition of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ); plasticizing the batch if necessary and shaping the batch; drying the body thus formed; and firing the formed body at 1,300° C. to 1,700° C. for 0.5 to 48 hours.
Claim 10
Dependent Claim
179 words
Low-expansion ceramics having a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-iron oxide as the major component of crystalline phase and that the ceramics have a coefficient of thermal expansion of not more than 20×10 -7 (1/°C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure 1,100° C. for 1,000 hours, said low-expansion ceramics being made by the process comprising the steps of preparing a batch of compounds so as to provide a chemical composition of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ); plasticizing the batch if necessary and shaping the batch; drying the body thus formed; and firing the formed body at 1,300° C. to 1,700° C. for 0.5 to 48 hours.
Claim 11
Dependent Claim
66 words
Low-expansion ceramics as defined in claim 7, wherein said chemical composition consists of 2.5 to 17% by weight of magnesia (MgO), 13.5 to 62% by weight of alumina (Al 2 O 3 ), 31.5 to 75% by weight of titanium in terms of titanium oxide (TiO 2 ), and 2 to 10% by weight of iron in terms of ferric oxide (Fe 2 O 3 ).
Claim 12
Dependent Claim
114 words
Low-expansion ceramics as defined in claim 7, wherein said compounds so selected as to provide the chemical composition of 1.5 to 20% by weight of magnesia (MgO), 6 to 68% by weight of alumina (Al 2 O 3 ), 24 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe 2 O 3 ) are in a mixture of materials selected from the group consisting of magnesia, magnesium carbonate, magnesium hydroxide, alumina, aluminum hydroxide, anatase type titanium dioxide, rutile type titanium dioxide, metallic iron, α type ferric oxide, γ-type ferric oxide, hydrous iron oxide, and ilmenite.
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) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |