Cordierite-based composite membrane coated on cordierite monolith

• US 8,784,541 B2
• Filed: 11/10/2011
• Issued: 07/22/2014
• Est. Priority Date: 11/10/2011
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Clinton, Joel Edward, Gu, Yunfeng
• Primary Examiner(s): Greene, Jason M
• Application Number:
  US13/293,745
• Publication Number:
  US 20130118355A1
• Time in Patent Office: 985 Days
• Field of Search: 96/4, 96/11, 95/45, 554/87, 555/23, 427/201, 427/244, 427/245, 427/372.2, 428/116
• US Class Current: 96/11
• CPC Class Codes: B01D 2323/12 Specific ratios of components used
• CPC Class Codes: B01D 2325/02834 more than 0.1 and up to 1 µm
• CPC Class Codes: B01D 2325/20 Specific permeability or cut-off range
• CPC Class Codes: B01D 63/066 with a porous block having membrane coated passages
• CPC Class Codes: B01D 67/0046 by slurry techniques, e.g. die or slip-casting
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/024 Oxides
• CPC Class Codes: C04B 2111/00801 Membranes; Diaphragms
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• 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 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/602 Making the green bodies or pre-forms by moulding
• CPC Class Codes: C04B 2235/606 Drying
• CPC Class Codes: C04B 2235/6567 Treatment time
• CPC Class Codes: C04B 35/117 Composites
• CPC Class Codes: C04B 35/195 Alkaline earth aluminosilicates, e.g. cordierite or anorthite
• 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 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4539 : as a emulsion, dispersion or suspension
• CPC Class Codes: C04B 41/4547 : characterised by the grain distribution
• CPC Class Codes: C04B 41/4582 : Porous coatings, e.g. coating containing porous fillers
• CPC Class Codes: C04B 41/5024 : Silicates C04B41/5022 takes precedence; silico-fluorides C04B41/5018
• CPC Class Codes: C04B 41/5025 : with ceramic materials copper oxide or solid solutions thereof C04B41/5074
• CPC Class Codes: C04B 41/5031 : Alumina
• CPC Class Codes: C04B 41/85 : with inorganic materials
• CPC Class Codes: Y10T 428/24149 : Honeycomb-like

Abstract

Composite-membrane monoliths include a cordierite monolith having a cordierite-ceramic composite membrane bonded to surfaces thereof with a surface median pore size. The cordierite-ceramic composite membrane has membrane surfaces with a membrane median pore size of 0.3 μm or less. The cordierite-ceramic composite membrane may be a composite formed by firing the cordierite monolith subsequent to applying a cordierite-ceramic composite slip to surfaces thereof. The cordierite-ceramic slip may include cordierite particles and ceramic particles. The cordierite particles may have a cordierite median particle size smaller than the surface median pore size. The ceramic particles may have a ceramic median particle size smaller than the cordierite median particle size.

Claims

1. A composite-membrane monolith comprising:

a cordierite monolith having surfaces with a surface median pore size of from about 1 μ

m to about 15 μ

m; and

a cordierite-ceramic composite membrane bonded directly to surfaces of the cordierite monolith without any intervening layer between the cordierite monolith and the cordierite-ceramic composite, the cordierite-ceramic composite having membrane surfaces with a membrane median pore size of 0.3 μ

m or less and with small pores having small-pore sizes from 0.05 μ

m to 0.1 μ

m, the membrane median pore size and the small pores providing polymer coatability to the membrane surfaces,

wherein;

the cordierite-ceramic composite membrane is a composite having a thermal coefficient of expansion approximately equal to the thermal coefficient of expansion of the cordierite monolith and is formed from a cordierite-ceramic composite slip comprising;

from 30 wt. % to 90 wt. % cordierite particles having a cordierite median particle size from about 1 μ

m to about 3 μ

m and smaller than the surface median pore size; and

from 10 wt. % to 70 wt. % ceramic particles other than cordierite particles, the ceramic particles having a ceramic median particle size from about 0.05 μ

m to about 0.5 μ

m and smaller than the cordierite median particle size,

wherein a weight ratio of the cordierite particles to the ceramic particles in the cordierite-ceramic composite slip is from 9;

1 to 3;

7.

2. The composite-membrane monolith of claim 1, wherein the ceramic particles are a ceramic material selected from the group consisting of alumina, ceria, silica, zirconia, zeolite, mullite, titania, yttria, tin oxide, silicon carbide, silicon nitride, and mixtures thereof.

3. The composite-membrane monolith of claim 1, wherein the ceramic particles are alumina particles.

4. The composite-membrane monolith of claim 3, wherein the ceramic median particle size is from about 0.2 μ

m to about 0.3 μ

m.

5. The composite-membrane monolith of claim 1, wherein the weight ratio of the cordierite particles to the ceramic particles in the mixture is from 9:

1 to 3;

7.

6. The composite-membrane monolith of claim 1, wherein the membrane surfaces are crack-free.

7. A method for forming a composite-membrane monolith, the method comprising:

applying a cordierite-ceramic composite slip to surfaces of a cordierite monolith, the cordierite-ceramic composite slip comprising from 30 wt. % to 90 wt. % cordierite particles and from 10 wt. % to 70 wt. % ceramic particles other than cordierite particles to form a coated cordierite monolith, the surfaces of the monolith having a surface median pore size of from about 1 μ

m to about 15 μ

m, the cordierite particles having a cordierite median particle size from about 1 μ

m to about 3 μ

m and smaller than the surface median pore size, the ceramic particles having a ceramic median particle size from about 0.05 μ

m to about 0.5 μ

m and smaller than the cordierite median particle size, the weight ratio of the cordierite particles to the ceramic particles in the cordierite-ceramic composite slip being from 9;

1 to 3;

7; and

firing the coated cordierite monolith to form the composite-membrane monolith, the cordierite-ceramic composite slip forming, during the firing, a cordierite-ceramic composite membrane as a composite having a thermal coefficient of expansion approximately equal to the thermal coefficient of expansion of the cordierite monolith and bonded directly to the surfaces of the cordierite monolith without any intervening layer between the cordierite monolith and the cordierite-ceramic composite, the cordierite-ceramic membrane having membrane surfaces with a membrane median pore size of 0.3 μ

m or less and with small pores having small-pore sizes from 0.05 μ

m to 0.1 μ

m, the membrane median pore size and the small pores providing polymer coatability to the membrane surfaces.

8. The method of claim 7, wherein the membrane surface is crack-free.

9. The method of claim 7, wherein the ceramic particles are a ceramic material selected from the group consisting of alumina, ceria, silica, zirconia, zeolite, mullite, titania, yttria, tin oxide, silicon carbide, silicon nitride, and mixtures thereof.

10. The method of claim 7, wherein the ceramic particles are alumina particles.

11. The method of claim 7, wherein the firing comprises heating the coated cordierite monolith to a firing temperature of from about 900°

C. to about 1300°

C.

12. The method of claim 7, wherein the cordierite-ceramic composite slip further comprises an additional ingredient selected from the group consisting of binders, dispersants, and combinations thereof.

13. The method of claim 7, further comprising mixing a cordierite slip and a ceramic slip in appropriate proportions to form the cordierite-ceramic composite slip in which the weight ratio of the cordierite particles to the ceramic particles in the cordierite-ceramic composite slip is from 9:

1 to 3;

7.

14. The method of claim 13, further comprising:

mixing the cordierite particles with a vehicle, a grinding medium, and at least one ingredient selected from the group consisting of binders, dispersants, and antifoaming agents to form a cordierite mixture; and

milling the cordierite mixture until the cordierite particles therein have a median particle size from about 1 μ

m to about 3 μ

m and less than the surface median pore size of the cordierite monolith, to form the cordierite slip.

15. The method of claim 13, further comprising:

mixing the ceramic particles with a vehicle, a binder, and a dispersant to form the ceramic slip.

16. The method of claim 13, wherein the cordierite slip, the ceramic slip, and the cordierite-ceramic composite slip each have solids contents of from about 5 wt. % to about 30 wt. %, based on the combined weight of the cordierite particles and the ceramic particles present in the respective slip.