High cordierite-to-mullite ratio cordierite-mullite-aluminum magnesium titanate compositions and ceramic articles comprising same

• US 9,868,670 B2
• Filed: 09/05/2014
• Issued: 01/16/2018
• Est. Priority Date: 09/05/2014
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Backhaus-Ricoult, Monika, Tepesch, Patrick David, Wheaton, Bryan Ray
• Primary Examiner(s): ORLANDO, AMBER ROSE
• Application Number:
  US14/478,200
• Publication Number:
  US 20160068441A1
• Time in Patent Office: 1,229 Days
• CPC Class Codes: B01D 39/2068 Other inorganic materials, e.g. ceramics
• 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 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3218 Aluminium (oxy)hydroxides, e.g. boehmite, gibbsite, alumina sol
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• 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 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
• 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 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5463 Particle size distributions
• CPC Class Codes: C04B 2235/786 Micrometer sized grains, i.e. from 1 to 100 micron
• 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 2235/9607 : Thermal properties, e.g. thermal expansion coefficient
• CPC Class Codes: C04B 35/1015 : containing refractory metal compounds other than those covered by C04B35/103 - C04B35/106
• CPC Class Codes: C04B 35/478 : based on aluminium titanates
• CPC Class Codes: C04B 35/64 : Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F
• 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: F01N 3/08 : for rendering innocuous using electric or electrostatic separators F01N3/01; chemical aspects B01D53/92

Abstract

Disclosed are ceramic bodies comprised of composite cordierite-mullite-aluminum magnesium titanate (CMAT) ceramic compositions having high cordierite-to-mullite ratio and methods for the manufacture of same.

Claims

1. A ceramic article, comprising:

a pseudobrookite phase comprising predominately alumina, magnesia, and titania;

a second phase comprising cordierite; and

a third phase comprising mullite,

wherein the cordierite-to-mullite phase weight ratio is greater than or equal to 1.3 and less than or equal to 7.

2. The ceramic article of claim 1, wherein the cordierite-to-mullite phase weight ratio is greater than or equal to 1.3 and less than or equal to 2.5.

3. The ceramic article of claim 1, wherein the ceramic article comprises a total porosity % P greater than 40% by volume.

4. The ceramic article of claim 3, wherein the ceramic article comprises a total porosity % P greater than 56% by volume.

5. The ceramic article of claim 1, wherein the ceramic article comprises a coefficient of thermal expansion, as measured between 25-800°

C., of less than or equal to 14×

10<sup>−

7</sup>/K.

6. The ceramic article of claim 5, wherein the ceramic article comprises a coefficient of thermal expansion, as measured between 25-800°

C., of less than or equal to 11×

10<sup>−

7</sup>/K.

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

m to 30 μ

m.

8. The ceramic article of claim 1, comprising a strain tolerance=MOR/Emod greater than or equal to 0.11%, wherein MOR is the modulus of rupture at room temperature and Emod is the Young'"'"'s modulus of the ceramic article at room temperature.

9. The ceramic article of claim 1, further comprising a sintering aid comprising at least one of ceria, strontium oxide, calcium oxide, yttria, lanthanum oxide, and other rare earth oxide.

10. The ceramic article of claim 1, wherein individual grains of the cordierite have a median grain size diameter greater than 5.0 μ

m.

11. The ceramic article of claim 1, wherein grains of cordierite phase comprise substantially preferred crystal orientation comprising an axial i-ratio less than 0.57 and a tangential i-ratio greater than 0.75,

wherein i-ratio is the cordierite texture coefficient i-ratio=I₍₁₁₀₎/[I₍₁₁₀₎+I₍₀₀₂₎] derived from the Rietveld-deconvoluted X-ray Diff action (XRD) peak intensities I of the (110) and (002) cordierite diffraction peaks acquired on either a honeycomb cross section (web) for the axial i-ratio or a honeycomb wall surface for the tangential i-ratio.

12. The ceramic article of claim 1, wherein the pseudobrookite phase comprises crystals having a substantially preferred crystal orientation with directly adjacent cordierite grains, so that at the interface the negative expansion crystal direction of the pseudobrookite phase is preferentially oriented within the cordierite/pseudobrookite interface plane and shows less preference for an orientation perpendicular to the cordierite/pseudobrookite interface plane.

13. The ceramic article of claim 1, comprising greater than or equal to 50 wt % and less than or equal to 80 wt % pseudobrookite phase.

14. A diesel particulate filter comprising the ceramic article of claim 1, wherein the diesel particulate filter comprises a structure having a plurality of inlet and outlet gas channels.

15. A ceramic article comprising a first crystalline phase comprised predominantly of a solid solution of aluminum titanate and magnesium dititanate, a second crystalline phase comprising cordierite, and a third crystalline phase comprising mullite, 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 44% TiO₂;

from 5 to 25% SiO₂, and a sintering aid, wherein the cordierite-to-mullite phase weight ratio is greater than or equal to 1.3 and less than or equal to 7.

16. The ceramic article of claim 15, comprising a median pore size d₅₀ in a range of 10 μ

m to 30 μ

m; and

a strain tolerance=MOR/Emod greater than or equal to 0.11%, wherein MOR is the modulus of rupture at room temperature and Emod is the Young'"'"'s modulus of the ceramic article at room temperature,

wherein the ceramic article comprises a coefficient of thermal expansion, as measured between 25-800°

C., of less than or equal to 11×

10<sup>−

7</sup>/K,

wherein the ceramic article comprises a total porosity % P greater than 50% by volume,

wherein the cordierite-to-mullite phase weight ratio is greater than or equal to 1.3 and less than or equal to 2.5.

17. A method of manufacturing a ceramic article, comprising:

providing an inorganic batch composition comprising a magnesia source, a silica source, an alumina source, a titania source, and at least one sintering aid;

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 pseudobrookite phase comprising predominately alumina, magnesia, and titania, a second phase comprising cordierite, and a third phase comprising mullite,

wherein the cordierite-to-mullite phase weight ratio is greater than or equal to 1.3 and less than or equal to 4.

18. The method of claim 17, wherein the cordierite-to-mullite phase weight ratio is greater than or equal to 1.3 and less than or equal to 2.5.

19. The method of claim 17, wherein the cordierite-to-mullite phase weight ratio is greater than or equal to 1.8 and less than or equal to 2.2.

20. The method of claim 17, wherein the plasticized ceramic precursor batch composition is shaped by extrusion.

21. The method of claim 17, wherein the firing conditions effective to convert the green body into a ceramic article comprise heating the green body at a hold temperature in the range of 1250°

C. to 1450°

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