Low-expansion ceramics and method of producing the same
First Claim
1. Low-expansion ceramics having the chemical composition of the ceramics essentially consisting of 1.2 to 20% by weight of magnesia (MgO), 6.5 to 68% by weight of alumina (Al2 O3), 19 to 80% by weight of titanium in terms of titanium oxide (TiO2), 1 to 20% by weight of silica (SiO2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe2 O3);
- wherein the major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-silicon oxide-iron oxide; and
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., a four-point flexural strength of not smaller than 50 kg/cm2 at room temperature, and a melting point of not lower than 1,500°
C.
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Abstract
The invention relates to low-expansion ceramics, the chemical composition of which consists of 1.2 to 20% by weight of magnesia (MgO), 6.5 to 68% by weight of alumina (Al2 O3), 19 to 80% by weight of titanium in terms of titanium oxide (TiO2), 1 to 20% by weight of silica (SiO2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe2 O3); the major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-silicon oxide-iron oxide; 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., a four-point flexural strength of not smaller than 50 kg/cm2 at room temperature, and a melting point of not lower than 1,500° C.; and a method of producing low-expansion ceramics comprising the steps of preparing a batch, plasticizing the batch, if necessary, and shaping the batch; drying the body thus shaped; and firing the shaped body at 1,300° C. to 1,700° C., thereby producing ceramics having a coefficient of thermal expansion of not more than 20×10-7 (1/°C.) in a temperature range of 25° C. to 800° C., a four-point flexural strength of not smaller than 50 kg/cm2 at room temperature, and a melting point of not lower than 1,500° C., and wherein the shape of ceramics is a honeycomb structure.
27 Citations
12 Claims
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1. Low-expansion ceramics having the chemical composition of the ceramics essentially consisting of 1.2 to 20% by weight of magnesia (MgO), 6.5 to 68% by weight of alumina (Al2 O3), 19 to 80% by weight of titanium in terms of titanium oxide (TiO2), 1 to 20% by weight of silica (SiO2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe2 O3);
- wherein the major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-silicon oxide-iron oxide; and
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., a four-point flexural strength of not smaller than 50 kg/cm2 at room temperature, and a melting point of not lower than 1,500°
C. - View Dependent Claims (2, 3, 4)
- wherein the major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-silicon oxide-iron oxide; and
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5. A method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 1.2 to 20% by weight of magnesia (MgO), 6.5 to 68% by weight of alumina (Al2 O3), 19 to 80% by weight of titanium in terms of titanium oxide (TiO2), 1 to 20% by weight of silica (SiO2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe2 O3);
- plasticizing the batch if necessary and shaping the batch;
drying the body thus shaped; and
firing the shaped body at 1,300°
C. to 1,700°
C., thereby having a coefficient of thermal expansion of not more than 20×
10-7 (1/°
C.) in a temperature range of 25°
C. to 800°
C., a four-point flexural strength of not smaller than 50 kg/cm2 at room temperature, and a melting point of not lower than 1,500°
C. - View Dependent Claims (6, 7, 8)
- plasticizing the batch if necessary and shaping the batch;
-
9. Low-expansion ceramics having a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-silicon oxide-iron oxide as the major 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., a four-point flexural strength of not smaller than 50 kg/cm2 at room temperature, and a melting point of not lower than 1,500°
C., said low-expansion ceramics being prepared by the method comprising the steps of preparing a batch of compounds so as to provide a chemical composition of 1.2 to 20% by weight of magnesia (MgO), 6.5 to 68% by weight of alumina (Al2 O3), 19 to 80% by weight of titanium in terms of titanium oxide (TiO2), 1 to 20% by weight of silica (SiO2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe2 O3);
plasticizing the batch and shaping the batch;
drying the body thus shaped; and
firing the shaped body at 1,300°
C. to 1,700°
C. - View Dependent Claims (10, 11, 12)
- 10-7 (1/°
Specification
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- Resources
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Current AssigneeNGK Insulators Limited
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Original AssigneeNGK Insulators Limited
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InventorsMatsuhisa, Tadaaki, Oda, Isao
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Primary Examiner(s)McCarthy, Helen M.
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Application NumberUS06/152,314Time in Patent Office642 DaysField of Search106/73.33, 106/62US Class Current501/112CPC Class CodesC04B 35/195 Alkaline earth aluminosilic...C04B 35/478 based on aluminium titanates
