Cordierite aluminum magnesium titanate compositions and ceramic articles comprising same

• US 8,394,167 B2
• Filed: 06/27/2007
• Issued: 03/12/2013
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Merkel, Gregory Albert, Tepesch, Patrick David, Wusirika, Raja Rao
• Primary Examiner(s): ORLANDO, AMBER ROSE
• Application Number:
  US12/305,767
• Publication Number:
  US 20100237007A1
• Time in Patent Office: 2,085 Days
• Field of Search: 55522-524, 422169-172, 422177-182
• US Class Current: 55/523
• CPC Class Codes: B01D 2279/30 for treatment of exhaust gases from IC Engines
• CPC Class Codes: B01D 46/2418 Honeycomb filters used for filtering exhaust gases of an internal combustion engine F01N3/022; ceramic honeycomb structures per se C04B38/0006
• CPC Class Codes: B01D 46/24491 Porosity
• CPC Class Codes: B01D 46/24492 Pore diameter
• CPC Class Codes: B01D 46/24494 Thermal expansion coefficient, heat capacity or thermal conductivity
• CPC Class Codes: B01J 35/56 Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• CPC Class Codes: C04B 2111/00793 as filters or diaphragms
• CPC Class Codes: C04B 2111/0081 as catalysts or catalyst carriers
• CPC Class Codes: C04B 2111/2084 Thermal shock resistance
• CPC Class Codes: C04B 2111/32 Expansion-inhibited materials
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3222 Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3227 Lanthanum oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3234 Titanates, not containing zirconia
• CPC Class Codes: C04B 2235/3236 Alkaline earth titanates
• CPC Class Codes: C04B 2235/3272 Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids, or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint glass constituents C04B2235/36
• CPC Class Codes: C04B 2235/3445 : Magnesium silicates, e.g. forsterite
• CPC Class Codes: C04B 2235/3463 : Alumino-silicates other than clay, e.g. mullite
• CPC Class Codes: C04B 2235/3481 : Alkaline earth metal alumino-silicates other than clay, e.g. cordierite, beryl, micas such as margarite, plagioclase feldspars such as anorthite, zeolites such as chabazite
• CPC Class Codes: C04B 2235/656 : characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/6562 : Heating rate
• CPC Class Codes: C04B 2235/80 : Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 35/195 : Alkaline earth aluminosilicates, e.g. cordierite or anorthite
• CPC Class Codes: C04B 35/465 : based on alkaline earth metal titanates
• CPC Class Codes: C04B 35/478 : based on aluminium titanates
• CPC Class Codes: C04B 38/0006 : Honeycomb structures from one or more corrugated sheets by winding or stacking C04B38/0083
• CPC Class Codes: C04B 38/0054 : the pores being microsized or nanosized
• CPC Class Codes: C04B 38/0074 : expressed as porosity percentage
• CPC Class Codes: C04B 38/0645 : Burnable, meltable, sublimable materials
• CPC Class Codes: C04B 38/068 : Carbonaceous materials, e.g. coal, carbon, graphite, hydrocarbons
• CPC Class Codes: F01N 3/0222 : the structure being monolithic, e.g. honeycombs
• CPC Class Codes: Y10T 428/24149 : Honeycomb-like

Abstract

Disclosed are ceramic bodies comprised of composite cordierite aluminum magnesium titanate ceramic compositions and methods for the manufacture of the same.

Claims

1. A ceramic article comprising a first crystalline phase comprised predominantly of a solid solution of aluminum titanate and magnesium dititanate and a second crystalline phase comprising cordierite, the article having a composition, as expressed in weight percent on an oxide basis of from 4 to 10% MgO;

from 40 to 55% Al₂O₃;

from 25 to 35% TiO₂; and

from greater than 13 to 25% SiO₂, wherein the ceramic article comprises a total porosity % P greater than 40% by volume and a coefficient of thermal expansion, as measured between 25-1000°

C., of less than or equal to 15×

10<sup>−

7</sup>/°

C.

2. The ceramic article of claim 1 having a composition expressed on an oxide basis of:

a(Al₂TiO₅)+b(MgTi₂O₅)+c(2MgO.2Al₂O₃.5SiO₂)+d(3Al₂O₃. 2SiO₂)+e(MgO.Al₂O₃)+f(2MgO.TiO₂)+g(Y₂O₃)+h(La₂O₃)+i(Fe₂O₃.TiO₂)+j(TiO₂), wherein a, b, c, d, e, f, g, h, i, and j are weight fractions of each component such that (a+b+c+d+e+f+g+h+i+j)=1.00, and wherein 0.3≦

a≦

0.75, 0.075≦

b≦

0.3, 0.02≦

c≦

0.5, 0.0≦

d≦

0.4,

0.0≦

e≦

0.25, 0.0≦

f≦

0.1, 0.0≦

g≦

0.05, 0.0≦

h≦

0.05, 0.0≦

i≦

0.05, and 0.0≦

j≦

0.2.

3. The ceramic article of claim 1 having a composition, as expressed in weight percent on an oxide basis:

of from 5 to 10% MgO;

from 40 to 50% A1203;

from 30 to 35% TiO2; and

from greater than 13 to 20% SiO2.

4. The ceramic article of claim 1, further comprising a total porosity % P greater than 50% by volume.

5. The ceramic article of claim 1, comprising a coefficient of thermal expansion, as measured between 25-1000°

C., less than or equal to 15×

10<sup>−

7</sup>/°

C.

6. The ceramic article of claim 5, comprising a coefficient of thermal expansion, as measured between 25-1000°

C., less than or equal to 10×

10<sup>−

7</sup>/°

C.

7. The ceramic article of claim 1, comprising a median pore size d₅₀ in the range of from 10 μ

m to 30 μ

m.

8. The ceramic article of claim 7, comprising a median pore size d₅₀ in the range of from 18 μ

m to 25 μ

m.

9. A diesel particulate filter comprising the ceramic article of claim 1, wherein said diesel particulate filter comprises a honeycomb structure having a plurality of axially extending end-plugged inlet and outlet cells.

10. A method of manufacturing a ceramic article, comprising the steps of:

providing an inorganic batch composition comprising a magnesia source, a silica source, an alumina source, and a titania source;

mixing the inorganic batch composition together with one or more processing aid selected from the group consisting of a plasticizer, lubricant, binder, pore former, and solvent, to form a plasticized ceramic precursor batch composition;

shaping the plasticized ceramic precursor batch composition into a green body; and

firing the green body under conditions effective to convert the green body into a ceramic article comprising a first crystalline phase comprised predominantly of a solid solution of aluminum titanate and magnesium dititanate and a second crystalline phase comprising cordierite, the article having a composition, as expressed in weight percent on an oxide basis of from 4 to 10% MgO;

from 40 to 55% Al₂O₃;

from 25 to 35% TiO₂; and

from greater than 13 to 25% SiO₂, wherein the ceramic article comprises a total porosity % P greater than 40% by volume and a coefficient of thermal expansion, as measured between 25-1000°

C., of less than or equal to 15×

10<sup>−

7</sup>/°

C.

11. The method of claim 10, wherein the inorganic batch composition further comprises at least one metal oxide sintering aid.

12. The method of claim 11, wherein the metal oxide sintering aid comprises at least one of yttrium oxide or lanthanide oxide.

13. The method of claim 10, wherein the inorganic batch composition further comprises iron as iron oxide or Fe₂TiO₅.

14. The method of claim 11, wherein at least one metal oxide is present, on a weight percent oxide basis, in an amount in the range of from greater than 0 to 5 weight % relative to the total weight of the inorganic batch composition.

15. The method of claim 13, wherein the Fe₂TiO₅ is present, on a weight percent oxide basis, in an amount in the range of from greater than 0 to 3 weight % relative to the total weight of the inorganic batch composition.

16. The method of claim 10, wherein the plasticized ceramic precursor batch composition is shaped by extrusion through a die.

17. The method of claim 10, wherein the shaped green body is a honeycomb.

18. The method of claim 10, wherein the firing conditions effective to convert the green body into a ceramic article comprise heating the green body at a maximum soak temperature in the range of from 1250°

C. to 1450°

C. and maintaining the maximum soak temperature for a hold time sufficient to convert the green body into a ceramic article.

19. The method of claim 18, wherein the maximum soak temperature is in the range of from 1300°

C. to 1350°

C. and wherein the hold time is in the range of from 2 to 24 hours.