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

Patent metadata

Field	Value
Publication number	US-9868670-B2
Application number	US-201414478200-A
Country	US
Kind code	B2
Filing date	Sep 5, 2014
Priority date	Sep 5, 2014
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

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.

First claim

What is claimed is:

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 −7 /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 −7 /K.

7. The ceramic article of claim 1 , comprising a median pore size d 50 in a range of 10 μm to 30 μm.

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 μm.

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% Al 2 O 3 ; from 25 to 44% TiO 2 ; from 5 to 25% SiO 2 , 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 d 50 in a range of 10 μm to 30 μm; 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 −7 /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.

Assignees

• Backhaus-Ricoult Monika
• Tepesch Patrick David
• Wheaton Bryan Ray
• Corning Inc

Inventors

• Backhaus-Ricoult Monika
• Tepesch Patrick David
• Wheaton Bryan Ray

Classifications

• C04B38/0006

  Honeycomb structures (from one or more corrugated sheets by winding or stacking C04B38/0083) · CPC title

• C04B2235/3481

  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 title

• C04B2235/3213

  Strontium oxides or oxide-forming salts thereof · CPC title

• C04B2235/3445

  Magnesium silicates, e.g. forsterite · CPC title

• C04B2235/3206

  Magnesium oxides or oxide-forming salts thereof · CPC title