US4307198A
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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 having a chemical composition of the ceramics essentially consisting of 2 to 20% by weight of magnesia (MgO), 10 to 68% by weight of alumina (Al 2 O 3 ), and 30 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), wherein the major component of crystalline phase thereof is magnesium-alumium-titanate phase, and 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., wherein the magnesium-alumium-titanate phase as the major component of the crystalline phase thereof is given by a chemical formula Mg 10x Al 8y Ti 5 (1-x-y) O.sub.(10+2y), here 0.02≦x≦0.20, 0.10≦y≦0.68, and 0.20≦(x+y)≦0.70, and a method of producing low-expansion ceramics, said method comprising steps of preparing a batch of compounds so as to provide a chemical composition of 2 to 20% by weight of magnesia, 10 to 68% by weight of alumina, and 30 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ); plasticizing the batch if necessary and shaping the batch by a means selected from the group consisting of extrusion, pressing, slip casting, and injection molding; drying the body thus formed; and firing the shaped body at 1,300° C. to 1,700° C. for 0.5 to 48 hours, whereby ceramics have a magnesium-aluminum-titanate phase as main component of crystalline phase thereof, 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. The ceramics of the invention can be widely used as ceramics material in the fields where high degree of heat-resistance, thermal shock-resistance, wear-resistance and corrosion-resistance are required.
Inventors
- 👤 Isao Oda
- 👤 Tadaaki Matsuhisa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:56
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/478; Y; Y10; Y10S; Y10S502/00; Y10S502/524
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
96 words
Low-expansion ceramics having a chemical composition of the ceramics essentially consisting of 2 to 20% by weight of magnesia (MgO), 10 to 68% by weight of alumina (Al 2 O 3 ), and 30 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), wherein the major component of crystalline phase thereof is magnesium-aluminum-titanate phase, and 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.
Claim 2
Dependent Claim
96 words
Low-expansion ceramics having a chemical composition of the ceramics essentially consisting of 2 to 20% by weight of magnesia (MgO), 10 to 68% by weight of alumina (Al 2 O 3 ), and 30 to 80% by weight of titanium in terms of titanium oxide (TiO 2 ), wherein the major component of crystalline phase thereof is magnesium-aluminum-titanate phase, and 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.
Claim 3
Dependent Claim
39 words
Low-expansion ceramics as defined in claim 1, wherein the magnesium-aluminum-titanate phase as the major component of the crystalline phase thereof is given by a chemical formula Mg 10x Al 8y Ti 5 (1-x-y) O.sub.(10+2y), here 0.02≦x≦0.20, 0.10≦y≦0.68, and 0.20≦(x+y)≦0.70.
Claim 4
Dependent Claim
51 words
Low-expansion ceramics as defined in claim 1, wherein the chemical composition thereof essentially consists of 3 to 17% by weight of magnesia (MgO), 15 to 62% by weight of alumina (Al 2 O 3 ), and 35 to 75% by weight of titanium in terms of titanium oxide (TiO 2 ).
Claim 5
Dependent Claim
39 words
Low-expansion ceramics as defined in claim 3, wherein the magnesium-aluminum-titanate phase as the major component of the crystalline phase thereof is given by a chemical formula Mg 10x Al 8y Ti 5 (1-x-y) O.sub.(10+2y), here 0.03≦x≦0.17, 0.15≦y≦0.62, and 0.25≦(x+y)≦0.65.
Claim 6
Dependent Claim
42 words
Low-expansion ceramics as defined in claim 1, wherein the major component of the crystalline phase thereof is magnesium-aluminum-titanate phase and contains not more than 20% of by weight at least one crystal selected from the group consisting of rutile, spinel, and corundum.
Claim 7
Dependent Claim
16 words
Low-expansion ceramics as defined in claim 1, wherein a shape of ceramics is a honeycomb structure.
Claim 8
Independent Claim
119 words
A method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 2 to 20% by weight of magnesia, 10 to 68% by weight of alumina, and 30 to 80% by weight of titanium in terms of titanium oxide; shaping the batch; drying the body thus formed, and firing the shaped body at 1,300° C. to 1,700° C. for 0.5 to 48 hours, whereby ceramics have a magnesium-aluminum-titanate phase as main component of crystalline phase thereof, 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.
Claim 9
Independent Claim
119 words
A method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 2 to 20% by weight of magnesia, 10 to 68% by weight of alumina, and 30 to 80% by weight of titanium in terms of titanium oxide; shaping the batch; drying the body thus formed, and firing the shaped body at 1,300° C. to 1,700° C. for 0.5 to 48 hours, whereby ceramics have a magnesium-aluminum-titanate phase as main component of crystalline phase thereof, 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.
Claim 10
Dependent Claim
48 words
A method of producing low-expansion ceramics as defined in claim 7, wherein said batch provides a chemical composition consisting essentially of 3 to 17% by weight of magnesia, 15 to 62% by weight of alumina, and 35 to 75% by weight of titanium in terms of titanium oxide.
Claim 11
Dependent Claim
75 words
A method of producing low expansion ceramics as defined in claim 7, wherein said compounds so selected as to provide the chemical composition of 2 to 20% by weight of magnesia, 10 to 68% by weight of alumina, and 30 to 80% by weight of titanium in terms of titanium oxide are selected from the group consisting of magnesia, magnesia carbonate, magnesium hydroxide, alumina, aluminum hydroxide, anatase type titanium dioxide, and rutile type titanium dioxide.
Claim 12
Dependent Claim
125 words
Low-expansion ceramics having a magnesium-aluminum-titanate phase as main component of crystalline phase thereof, 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 low-expansion ceramics being produced by a process comprising the steps of preparing a batch of compounds so as to provide a chemical composition of 2 to 20% by weight of magnesia, 10 to 68% by weight of alumina, and 30 to 80% by weight of titanium in terms of titanium oxide; shaping said batch into a body; drying said body thus formed, and firing the shaped body at 1,300° C. to 1,700° C. for 0.5 to 48 hours.
Claim 13
Dependent Claim
125 words
Low-expansion ceramics having a magnesium-aluminum-titanate phase as main component of crystalline phase thereof, 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 low-expansion ceramics being produced by a process comprising the steps of preparing a batch of compounds so as to provide a chemical composition of 2 to 20% by weight of magnesia, 10 to 68% by weight of alumina, and 30 to 80% by weight of titanium in terms of titanium oxide; shaping said batch into a body; drying said body thus formed, and firing the shaped body at 1,300° C. to 1,700° C. for 0.5 to 48 hours.
Claim 14
Dependent Claim
44 words
Low-expansion ceramics as defined in claim 10, wherein said batch provides a chemical composition consisting essentially of 3 to 17% by weight of magnesia, 15 to 62% by weight of alumina, and 35 to 75% by weight of titanium in terms of titanium oxide.
Claim 15
Dependent Claim
70 words
Low-expansion ceramics as defined in claim 10, wherein said compounds so selected as to provide the chemical composition of 2 to 20% by weight of magnesia, 10 to 68% by weight of alumina, and 30 to 80% by weight of titanium in terms of titanium oxide are selected from the group consisting of magnesia, magnesium carbonate, magnesium hydroxide, alumina, aluminum hydroxide, anatase type titaniun dioxide, and rutile type titanium dioxide.
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 |