Method of coating a substrate with a particle stabilized foam

Patent metadata

Field	Value
Publication number	US-11618014-B2
Application number	US-201715483095-A
Country	US
Kind code	B2
Filing date	Apr 10, 2017
Priority date	Apr 11, 2016
Publication date	Apr 4, 2023
Grant date	Apr 4, 2023

Abstract

A method of coating a substrate with a foam is described. The method comprises:
(a) introducing a foam into a substrate comprising a plurality of channels through open ends of the channels at a first end of the substrate; and (b) applying at least one of (i) a vacuum to open ends of the channels at a second end of the substrate and (ii) a pressure to the open ends of the channels at the first end of the substrate; wherein the foam comprises a particulate material, and wherein the foam is particle stabilized.

First claim

The invention claimed is:

1. A method of coating a substrate with a foam, wherein the method comprises:
(a) introducing a particle-stabilized, alumina-based foam into a substrate comprising a plurality of channels through open ends of the channels at a first end of the substrate; and
(b) applying at least one member selected from the group consisting of (i) a vacuum to open ends of the channels at a second end of the substrate, wherein the vacuum draws the foam into the substrate through the open ends of the channels at the first end, and (ii) a pressure to the open ends of the channels at the first end of the substrate wherein the pressure pushes or blows the foam into the substrate through the open ends of the channels at the first end,
wherein the substrate is constructed of a material containing at least one of silicon carbide, aluminium nitride, silicon nitride, aluminium titanate, cordierite, mullite, pollucite, a thermet, an Fe—Cr—Al alloy, a Ni—Cr—Al alloy, and a stainless-steel alloy;
wherein the substrate is a honeycomb monolith substrate having a plurality of channels that extend longitudinally along the length of the substrate; and
wherein the foam comprises a particulate material.

2. A method according to claim 1 further comprising the step of (c) drying and/or calcining the substrate containing the particle stabilized foam to obtain a solid foam layer disposed or supported on the substrate.

3. A method according to claim 2 , wherein the solid foam layer comprises an open cell structure.

4. A method according to claim 2 , wherein the solid foam layer has a cell volume, wherein more than 20% of the cell volume is interconnected.

5. A method according to claim 1 , wherein step (a) comprises the steps of (i) holding the substrate substantially vertically and (ii) pushing or injecting the foam into the substrate through the open ends of the channels at the first end.

6. A method according to claim 5 , wherein step (ii) pushing or injecting the foam into the substrate, then this may be (ii) pushing or injecting the foam using a piston.

7. A method according to claim 1 , wherein the foam is obtained by a method comprising the steps of: (i) preparing a suspension of the particulate material in an aqueous medium; and (ii) foaming the suspension by introducing a gas into the suspension to generate a particle-stabilised foam.

8. A method according to claim 7 , wherein step (i) is a step of preparing a suspension of a particulate material in an aqueous medium containing an amphiphile.

9. A method according to claim 1 , wherein step (a) comprises the steps of: (i) locating a containment means on top of the first end of the substrate, (ii) dosing the foam into the containment means.

10. A method according to claim 1 , wherein the particulate material has a median particle size of 1 nm to 50 μm.

11. A method according to claim 1 , wherein the foam contains bubbles having a diameter from 1 μm to 1 mm.

12. A method according to claim 1 wherein step (b) comprises applying a vacuum to open ends of the channels at a second end of the substrate, wherein the vacuum draws the foam into the substrate through the open ends of the channels at the first end.

13. A method according to claim 1 wherein the particulate material is a catalytic material comprising a catalytically active metal supported on a support material.

14. A method according to claim 1 wherein the foam contains bubbles having a diameter from 10 to 300 μm.

Assignees

• Johnson Matthey Plc

Inventors

• Bernadini Cecilia
• Campbell Thomas
• Chandler Guy Richard
• Daly Christopher
• Hardstone Katharine Ann
• Hotchkiss Thomas
• Thompsett David

Classifications

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J35/56

  Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths · CPC title

• B01J35/50

  characterised by their shape or configuration · CPC title

• F01N3/10

  by thermal or catalytic conversion of noxious components of exhaust · CPC title

• B01J23/42 Primary

  Platinum · CPC title