Aluminum titanate-mullite base ceramics

Claim 2

A sintered aluminum titanate-mullite base ceramic consisting essentially of: a chemical composition of not greater than 0.8% of MgO, 53 to 74% of Al 2 O 3 , 14 to 33% of TiO 2 , 1.2 to 5% of Fe 2 O 3 , 6 to 20% of SiO 2 , and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, and an amount of glass in mullite base matrices of the sintered ceramic being not greater than 5% when measured at a section of a body of said sintered ceramic; said sintered aluminum titanate-mullite base ceramic being formed by compounding 40 to 65% of a raw material of aluminum titanate consisting essentially of 45 to 62% of Al 2 O 3 , 34 to 50% of TiO 2 , 3 to 7% of Fe 2 O 3 , not greater than 1% of SiO 2 and (CaO+Na 1 O+K 2 O) in an amount not greater than 0.3%, with 35 to 60% of a raw material of mullite consisting essentially of 18 to 32% of SiO 2 , 68 to 82% of Al 2 O 3 , and (Fe 2 O 3 +TiO 2 +CaO+MgO+Na 2 O+K 2 O) in an amount not greater than 0.8%, at least one of said aluminum titanate raw material and said mullite raw material being preliminarily fired at a temperature which is not less than 1550° C., molding a resulting mixture of the raw materials, and subsequently firing a thus obtained molding at 1,550° to 1,700° C. in an oxidizing atmosphere resulting in a sintered aluminum titanate-mullite base ceramic article; said article having an average coefficient of thermal expansion at a temperature range of 40° to 800° C. of -2.0×10 -6 /°C. to 2.0×10 -6 /°C.; said article having an increment in a linear dimension which is not greater than 1.0% after said article has been exposed forty times to a thermal cycling at a temperature rising from 40° C. to 1,260° C. in a time of 6 minutes and cooling from 1,260° C. to 40° C. in a time of 5 minutes; and said article having a maximum difference value between a value on a thermal expansion curve during heating and a value on a thermal expansion curve during cooling at an identical temperature which is not greater than 0.18%.

Claim 3

A sintered aluminum titanate-mullite base ceramic consisting essentially of: a chemical composition of not greater than 0.8% of MgO, 53 to 74% of Al 2 O 3 , 14 to 33% of TiO 2 , 1.2 to 5% of Fe 2 O 3 , 6 to 20% of SiO 2 , and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, and an amount of glass in mullite base matrices of the sintered ceramic being not greater than 5% when measured at a section of a body of said sintered ceramic; said sintered aluminum titanate-mullite base ceramic being formed by compounding 40 to 65% of a raw material of aluminum titanate consisting essentially of not greater than 1% of MgO, 45 to 62% of Al 2 O 3 , 34 to 50% of TiO 2 , 3 to 7% of Fe 2 O 3 , not greater than 1% of SiO 2 and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, with 35 to 60% of a raw material of mullite consisting essentially of 18 to 32% of SiO 2 , 68 to 82% of Al 2 O 3 , and (Fe 2 O 3 +TiO 2 +CaO+MgO+Na 2 O+K 2 O) in an amount not greater than 0.85%, at least one of said aluminum titanate raw material and said mullite raw material being preliminarily fired at a temperature which is not less than 1550° C., molding a resulting mixture of the raw materials, and firing a thus obtained molding at 1,550° to 1,700° C. in an oxidizing atmosphere resulting in a sintered aluminum titanate-mullite base ceramic article. said article having an average coefficient of thermal expansion at a temperature range of 40° to 800° C. of -2.0×10 -6 /°C. to 2.0×10 -6 /°C.; said article having an increment in a linear dimension which is not greater than 1.0% after said article has been exposed forty times to a thermal cycling at a temperature rising from 40° C. to 1,260° C. in a time of 6 minutes and cooling from 1,260° C. to 40° C. in a time of 5 minutes; and said article having a maximum difference value between a value on a thermal expansion curve during heating and a value on a thermal expansion curve during cooling at an identical temperature, which is not greater than 0.18%.

Claim 4

A sintered aluminum titanate-mullite base ceramic consisting essentially of: a chemical composition of not greater than 0.8% of MgO, 53 to 74% of Al 2 O 3 , 14 to 33% of TiO 2 , 1.2 to 5% of Fe 2 O 3 , 6 to 20% of SiO 2 , and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, and an amount of glass in mullite base matrices of the sintered ceramic being not greater than 5% when measured at a section of a body of said sintered ceramic; said sintered aluminum titanate-mullite base ceramic being formed by compounding 40 to 65% of a raw material of aluminum titanate consisting essentially of not greater than 1% of MgO, 45 to 62% of Al 2 O 3 , 34 to 50% of TiO 2 , 3 to 7% of Fe 2 O 3 , not greater than 1% of SiO 2 and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, with 35 to 60% of a raw material of mullite consisting essentially of 18 to 32% of SiO 2 , 68 to 82% of Al 2 O 3 , and (Fe 2 O 3 +TiO 2 +CaO+MgO+Na 2 O+K 2 O) in an amount not greater than 0.85%, at least one of said aluminum titanate raw material and said mullite raw material being preliminarily fired at a temperature which is not less than 1550° C., molding a resulting mixture of the raw materials, and firing a thus obtained molding at 1,550° to 1,700° C. in an oxidizing atmosphere resulting in a sintered aluminum titanate-mullite base ceramic article. said article having an average coefficient of thermal expansion at a temperature range of 40° to 800° C. of -2.0×10 -6 /°C. to 2.0×10 -6 /°C.; said article having an increment in a linear dimension which is not greater than 1.0% after said article has been exposed forty times to a thermal cycling at a temperature rising from 40° C. to 1,260° C. in a time of 6 minutes and cooling from 1,260° C. to 40° C. in a time of 5 minutes; and said article having a maximum difference value between a value on a thermal expansion curve during heating and a value on a thermal expansion curve during cooling at an identical temperature, which is not greater than 0.18%.

Claim 5

A sintered aluminum titanate-mullite base ceramic according to claim 1, wherein the content of (Na 2 O+K 2 O) in the aluminum titanate raw material is not greater than 0.15%.

Claim 6

A sintered aluminum titanate-mullite base ceramic according to claim 1, wherein the content of (Na 2 O+K 2 O) in the mullite starting material is not greater than 0.25%.

Claim 7

A sintered aluminum titanate-mullite base ceramic according to claim 2, wherein the content of (Na 2 O+K 2 O) in the aluminum titanate starting material is not greater than 0.15%.

Claim 8

A sintered aluminum titanate-mullite base ceramic according to claim 2, wherein the content of (Na 2 O+K 2 O) in the mullite material starting is not greater than 0.25%.

Claim 9

A sintered aluminum titanate-mullite base ceramic according to claim 1, wherein the ceramic is designed as a honeycomb structural body.

Claim 10

A sintered aluminum titanate-mullite base ceramic according to claim 2, wherein the ceramic is designed as a honeycomb structural body.

Claim 11

A sintered aluminum titanate-mullite base ceramic consisting essentially of: a chemical composition of not greater than 0.8% of MgO, 53 to 74% of Al 2 O 3 , 14 to 33% of TiO 2 , 1.2 to 5% of Fe 2 O 3 , 6 to 20% of SiO 2 , and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, and an amount of glass in mullite base matrices of the sintered ceramic being not greater than 5% when measured at a section of a body of said sintered ceramic; said sintered aluminum titanate-mullite base ceramic being formed by compounding 40 to 65% of a raw material of aluminum titanate consisting essentially of 45 to 62% of Al 2 O 3 , 34 to 50% of TiO 2 , 3 to 7% of Fe 2 O 3 , not greater than 1% of SiO 2 and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, with 35 to 60% of a raw material of mullite consisting essentially of 18 to 32% of SiO 2 , 68 to 82% of Al 2 O 3 , and (Fe 2 O 3 +TiO 2 +CaO+MgO+Na 2 O+K 2 O) in an amount not greater than 0.8%, at least one of said aluminum titanate raw material and said mullite raw material being preliminarily fired at a temperature which is not less than 1550° C., molding a resulting mixture of the raw materials, and subsequently firing a thus obtained molding at 1,550° to 1,700° C. in an oxidizing atmosphere resulting in a sintered aluminum titanate-mullite base ceramic article.

Claim 12

A sintered aluminum titanate-mullite base ceramic consisting essentially of: a chemical composition of not greater than 0.8% of MgO, 53 to 74% of Al 2 O 3 , 14 to 33% of TiO 2 , 1.2 to 5% of Fe 2 O 3 , 6 to 20% of SiO 2 , and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, and an amount of glass in mullite base matrices of the sintered ceramic being not greater than 5% when measured at a section of a body of said sintered ceramic; said sintered aluminum titanate-mullite base ceramic being formed by compounding 40 to 65% of a raw material of aluminum titanate consisting essentially of 45 to 62% of Al 2 O 3 , 34 to 50% of TiO 2 , 3 to 7% of Fe 2 O 3 , not greater than 1% of SiO 2 and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, with 35 to 60% of a raw material of mullite consisting essentially of 18 to 32% of SiO 2 , 68 to 82% of Al 2 O 3 , and (Fe 2 O 3 +TiO 2 +CaO+MgO+Na 2 O+K 2 O) in an amount not greater than 0.8%, at least one of said aluminum titanate raw material and said mullite raw material being preliminarily fired at a temperature which is not less than 1550° C., molding a resulting mixture of the raw materials, and subsequently firing a thus obtained molding at 1,550° to 1,700° C. in an oxidizing atmosphere resulting in a sintered aluminum titanate-mullite base ceramic article.

Claim 13

A sintered aluminum titanate-mullite base ceramic consisting essentially of: a chemical composition of not greater than 0.8% of MgO, 53 to 74% of Al 2 O 3 , 14 to 33% of TiO 2 , 1.2 to 5% of Fe 2 O 3 , 6 to 20% of SiO 2 , and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, and an amount of glass in mullite base matrices of the sintered ceramic being not greater than 5% when measured at a section of a body of said sintered ceramic.

Claim 14

A sintered aluminum titanate-mullite base ceramic consisting essentially of: a chemical composition of not greater than 0.8% of MgO, 53 to 74% of Al 2 O 3 , 14 to 33% of TiO 2 , 1.2 to 5% of Fe 2 O 3 , 6 to 20% of SiO 2 , and (CaO+Na 2 O+K 2 O) in an amount not greater than 0.3%, and an amount of glass in mullite base matrices of the sintered ceramic being not greater than 5% when measured at a section of a body of said sintered ceramic.