US4758542A
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Low thermal expansion ZrTiO4 --Al2 TiO5 --ZrO2 compositions
Assignee: Vibrantz Corp
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Filing: 1987-08-07
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Granted: 1988-07-19
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Expires: 2007-08-07
Abstract
Abstract A low thermal expansion ceramic composition having a predominant Al 2 TiO 5 phase along with zirconium titanate and zirconia phases. The final overall ceramic composition after firing has a low thermal expansion between 24°-1000° C. of not greater than 1.5×10 -6 ° C. -1 and a thermal stability in air such that (a) upon heating to 1200° C. for at least 4 hours there is substantially no decomposition of the Al 2 TiO 5 phase to rutile or alumina as measured by X-ray diffraction, (b) physical growth after thermal cycling between 200° and 1150° C. for 300 cycles does not exceed 1.5%, and (c) the composition maintains a low average thermal expansion between 24°-1000° C. of not greater than 1.5×10 -6 ° C. -1 after the isothermal heating or cycling conditions. The composition is preferably made by forming a mixture of the equivalent of 50-90 volume percent Al 2 TiO 5 or a solid solution having a substantial amount of Al 2 TiO 5 in the solid solution, and zirconium titanate and then heating the mixture at a temperature of 1250° C. or higher.
Inventors
- 👤 Frederick J. Parker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:48
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/48; C04B35/49; C04B35/46; C04B35/462; C04B35/478
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
136 words
A ceramic composition comprising a predominant Al 2 TiO 5 phase along with zirconium titanate and zirconia phases where the final overall ceramic composition has a low thermal expansion between 24°-1000° C. of not greater than 1.5×10 -6 ° C. -1 and a thermal stability in air such that (a) upon heating at 1200° C. for at least 4 hours there is substantially no decomposition of the Al 2 TiO 5 phase to rutile or alumina as measured by X-ray diffraction, (b) physical growth after thermal cycling between 200° and 1150° C. for 300 cycles does not exceed 1.5%, and (c) the composition maintains a low average thermal expansion between 24°-1000° C. of not greater than 1.5×10 -6 ° C. -1 after the isothermal heating at 1200° C. for at least 4 hours or cycling conditions.
Claim 2
Dependent Claim
136 words
A ceramic composition comprising a predominant Al 2 TiO 5 phase along with zirconium titanate and zirconia phases where the final overall ceramic composition has a low thermal expansion between 24°-1000° C. of not greater than 1.5×10 -6 ° C. -1 and a thermal stability in air such that (a) upon heating at 1200° C. for at least 4 hours there is substantially no decomposition of the Al 2 TiO 5 phase to rutile or alumina as measured by X-ray diffraction, (b) physical growth after thermal cycling between 200° and 1150° C. for 300 cycles does not exceed 1.5%, and (c) the composition maintains a low average thermal expansion between 24°-1000° C. of not greater than 1.5×10 -6 ° C. -1 after the isothermal heating at 1200° C. for at least 4 hours or cycling conditions.
Claim 3
Dependent Claim
48 words
A ceramic composition according to claim 1, further comprising in solid solution with at least the zirconium titanate or the Al 2 TiO 5 an oxide selected from the group consisting of ZrO 2 , TiO 2 , SiO 2 , Fe 2 O 3 and mixtures thereof.
Claim 4
Dependent Claim
38 words
A ceramic composition according to claim 2, wherein the Al 2 TiO 5 phase contains a phase decomposition stabilizer selected from the group consisting of SiO 2 , ZrO 2 , Fe 2 O 3 or mixtures thereof.
Claim 5
Dependent Claim
33 words
A ceramic composition according to claim 3, wherein the phase decomposition stabilizer oxide is present in an amount of from 1 to 5 mole % of the total Al 2 TiO 5 composition.
Claim 6
Dependent Claim
47 words
A ceramic composition according to claim 1, wherein the composition is made by firing at a temperature of 1250° C. or higher a starting mixture of a source of ZrO 2 , a source of TiO 2 , and a source of Al 2 O 3 .
Claim 7
Dependent Claim
52 words
A ceramic composition according to claim 5, wherein the starting mixture prior to firing comprises at least the equivalent of (a) 50-90 volume percent Al 2 TiO 5 or a solid solution having a substantial amount of Al 2 TiO 5 in the solid solution, and (b) 10-50 volume percent zirconium titanate.
Claim 8
Dependent Claim
35 words
A ceramic composition according to claim 6, wherein the zirconium titanate is in an amount from 10 to 50 volume percent, and has a composition within the range ZrTi 1+x O 4+2x , where 0≦x<1.
Claim 9
Dependent Claim
20 words
A ceramic composition according to claim 7, wherein the starting mixture further comprises a phase of free ZrO 2 .
Claim 10
Dependent Claim
19 words
A ceramic composition according to claim 8, wherein the free ZrO 2 further comprises TiO 2 in solid solution.
Claim 11
Dependent Claim
47 words
Ceramic compositions according to claim 5, wherein the starting mixture before firing comprises at least one pre-reacted phase of Al 2 TiO 5 , zirconium titanate or their solid solutions containing minor amounts of compatible oxides, and the components necessary to form the remaining phases after firing.
Claim 12
Dependent Claim
60 words
A ceramic composition according to claim 5, wherein the starting mixture before firing comprises a mixture of (a) the compound Al 2 TiO 5 or a solid solution of Al 2 TiO 5 containing minor amounts of compatible oxides in solid solution and (b) prereacted zirconium titanate made from about equal molar amounts of ZrO 2 and TiO 2 .
Claim 13
Dependent Claim
27 words
A ceramic composition according to claim 11 wherein the compatible oxide is selected from the group of SiO 2 , Fe 2 O 3 or mixtures thereof.
Claim 14
Dependent Claim
129 words
A method of making a low thermal expansion ceramic composition as defined in claim 1 comprising (1) forming a starting mixture of reactants prior to firing which stoichiometrically will have (a) 50-90 volume percent Al 2 TiO 5 or a solid solution having a substantial amount of Al 2 TiO 5 in the solid solution, and (b) 10-50 volume percent zirconium titanate; said mixture being either (i) prereacted Al 2 TiO 5 and prreacted zirconium titanate, (ii) prereacted Al 2 TiO 5 and sources of TiO 2 and ZrO 2 to form ziroconium titanate, or (iii) prereacted zirconium titanate and sources of Al 2 O 3 and TiO 2 to form Al 2 TiO 5 ; and (2) heating the mixture at a temperature of 1250° C. or higher.
Claim 15
Dependent Claim
34 words
A method according to claim 13, wherein the zirconium titanate is in an amount from 10 to 50 volume percent, and has a composition within the range ZrTi 1+x O 4+2x , where 0≦x<1.
Claim 16
Dependent Claim
16 words
A method according to claim 13, wherein the heating is done in the presence of air.
Claim 17
Dependent Claim
19 words
A method according to claim 14, wherein the starting mixture further comprises a phase of free ZrO 2 .
Claim 18
Dependent Claim
18 words
A method according to claim 16, wherein the free ZrO 2 further comprises TiO 2 in solid solution.
Claim 19
Dependent Claim
49 words
A method of making low thermal expansion ceramic compositions according to claim 13, comprising combining at least one pre-reacted phase of Al 2 TiO 5 and sources of TiO 2 and ZrO 2 to form zirconium titanate, and heating the mixture at a temperature of 1250° C. or higher.
Claim 20
Dependent Claim
51 words
A method of making low thermal expansion ceramic compositions according to claim 13, comprising combining at least one pre-reacted phase of zirconium titanate and sources of Al 2 O 3 and TiO 2 to form Al 2 TiO 5 and heating the mixture at a temperature of 1250° C. or higher.
Claim 21
Dependent Claim
46 words
A method of making low thermal expansion ceramic compositions according to claim 13, comprising combining Al 2 TiO 5 and prereacted zirconium titanate made from about equal amounts of ZrO 2 and TiO 2 and heating the mixture at a temperature of 1250° C. or higher.
Claim 22
Dependent Claim
31 words
A method according to claim 20, further comprising adding to the starting mixture a compatible oxide selected from the group of SiO 2 , Fe 2 O 3 or mixtures thereof.
Claim 23
Dependent Claim
22 words
An extruded catalyst support made of the low thermal expansion ceramic composition according to claim 1 and having good thermal shock resistance.
Claim 24
Dependent Claim
16 words
An extruded catalyst support according to claim 22, wherein the support has a honeycomb cross section.
Claim 25
Dependent Claim
22 words
An extruded catalyst support made of the low thermal expansion ceramic composition according to claim 5 and having good thermal shock resistance.
Claim 26
Dependent Claim
16 words
An extruded catalyst support according to claim 24, wherein the support has a honeycomb cross section.
Claim 27
Dependent Claim
22 words
An extruded catalyst support made of the low thermal expansion ceramic composition according to claim 6 and having good thermal shock resistance.
Claim 28
Dependent Claim
16 words
An extruded catalyst support according to claim 26, wherein the support has a honeycomb cross section.
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