Honeycomb body having porous material

Abstract

To provide a method for forming a honeycomb body improved in initial filtration efficiency (FE) and achieving a lower pressure loss.SOLUTION: A honeycomb body (100) has a porous ceramic honeycomb structure including a first end part (105), a second end part (135), and plural walls (115) having wall surfaces that define plural inside channels (110). A porous material is disposed on one or more of the wall surfaces of the honeycomb body (100). A method of forming the honeycomb body (100) includes a step of stacking a porous inorganic material on the ceramic honeycomb body (100) and a step of binding the porous inorganic material to the ceramic honeycomb body (100) to form a porous layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present specification relates to articles having porous bodies, such as porous ceramic honeycomb bodies, having a porous material, e.g., a material such as a filtration material, such as a porous inorganic layer, disposed on at least a portion of the porous body, and methods for making such articles and porous bodies. [Background technology]

[0002] Wall-flow filters are used to remove particulates from fluid exhaust streams, such as combustion engine exhaust. Examples include ceramic soot filters, which are used to remove particulates from diesel engine exhaust, and gasoline particulate filters (GPFs), which are used to remove particulates from gasoline engine exhaust. In wall-flow filters, exhaust gas to be filtered enters inlet cells, passes through cell walls, and exits the filter via outlet channels. As the gas passes through and then exits the filter, particulates are trapped on or within the inlet cell walls.

[0003] GPFs are used in conjunction with gasoline direct injection (GDI) engines, which emit more particulates than conventional gasoline engines. The European Union's Euro 6 emissions standard for vehicles, for example, requires a particulate count of 6 x 10 11 The ash cake is regulated to less than # / km. The gradual accumulation of ash cake on the GPF results in an improvement in filtration efficiency (FE). However, ash cake is characterized by relatively low particle packing porosity and poor durability. Ash cake accumulation can result in an increase in pressure drop across the filter, which can be detrimental to filter performance. Summary of the Invention [Problem to be solved by the invention]

[0004] Initial filtration efficiency (FE) is an attribute of GPFs. There is a continuing need to improve FE and achieve lower pressure drop. [Means for solving the problem]

[0005] Aspects of the present disclosure relate to porous bodies and methods for their manufacture and use.

[0006] According to one embodiment, the porous body comprises a porous ceramic or metal honeycomb body having a first end, a second end, and a plurality of porous walls having wall surfaces defining a plurality of internal channels. A porous material, e.g., a filtration material such as a porous inorganic layer, is disposed on one or more of the wall surfaces. In one or more embodiments, the filtration material such as a porous inorganic layer has a water solubility of about 20% to about 95%, or about 25% to about 95%, or about 30% to about 95%, or about 40% to about 95%, or about 45% to about 95%, or about 50% to about 95%, or about 55% to about 95%, or about 60% to about 95%, or about 65% to about 95%, or about 70% to about 95%, or about 75% to about 95%, or about 80% to about 95%, or about 8 ... 0% to about 95%, or about 45% to about 95%, or about 50% to about 95%, or about 55% to about 95%, or about 60% to about 95%, or about 65% to about 95%, or about 70% to about 95%, or about 75% to about 95%, or about 80% to about 95%, or about 85% to about 95%, or about 20% to about 90%, or about 25% to about 90%, or about 30% to about 90%, or about 40% to about 90%, or about 45% to about 90%, or about 50% to about 90%, or about 55% to about 90% , or about 60% to about 90%, or about 65% to about 90%, or about 70% to about 90%, or about 75% to about 90%, or about 80% to about 90%, or about 85% to about 90%, or about 20% to about 85%, or about 25% to about 85%, or about 30% to about 85%, or about 40% to about 85%, or about 45% to about 85%, or about 50% to about 85%, or about 55% to about 85%, or about 60% to about 85%, or about 65% to about 85%, or about 70% to about 85%, or about 75 The porous inorganic layer has a porosity in the range of 0.5 μm or more and 50 μm or less, or ...It has an average thickness of 5 μm or more and 45 μm or less, 0.5 μm or more and 40 μm or less, or 0.5 μm or more and 35 μm or less, or 0.5 μm or more and 30 μm or less, 0.5 μm or more and 25 μm or less, or 0.5 μm or more and 20 μm or less, or 0.5 μm or more and 15 μm or less, or 0.5 μm or more and 10 μm or less.

[0007] In another aspect, a method for forming a honeycomb body includes contacting a material, such as a filtration material, with a gaseous carrier fluid; depositing the material, such as a filtration material, on the ceramic honeycomb body by flowing the gaseous carrier fluid through the ceramic honeycomb body; and bonding the material, such as a filtration material, to the ceramic honeycomb body to produce a porous material, such as a filtration material, which may be a porous inorganic layer. The deposited material, such as the filtration material, which may be a porous inorganic layer, may be from about 20% to about 95%, or from about 25% to about 95%, or from about 30% to about 95%, or from about 40% to about 95%, or from about 45% to about 95%, or from about 50% to about 95%, or from about 55% to about 95%, or from about 60% to about 95%, or from about 65% to about 95%, or from about 70% to about 95%, or from about 75% to about 95%, or from about 80% to about 95%, or from about 85% to about 95%, or from about 30% to about 95%, or or about 40% to about 95%, or about 45% to about 95%, or about 50% to about 95%, or about 55% to about 95%, or about 60% to about 95%, or about 65% to about 95%, or about 70% to about 95%, or about 75% to about 95%, or about 80% to about 95%, or about 85% to about 95%, or about 20% to about 90%, or about 25% to about 90%, or about 30% to about 90%, or about 40% to about 90%, or about 45% to about 90%, or about 50% to about 90%, or about 55% to about 90%, or about 60% to about 90%, or about 65% to about 90%, or about 70% to about 90%, or about 75% to about 90%, or about 80% to about 90%, or about 85% to about 90%, or about 20% to about 85%, or about 25% to about 85%, or about 30% to about 85%, or about 40% to about 85%, or about 45% to about 85%, or about 50% to about 85%, or about 55% to about 85%, or about 60% to about 85%, or having a porosity in the range of about 65% to about 85%, or about 70% to about 85%, or about 75% to about 85%, or about 80% to about 85%, or about 20% to about 80%, or about 25% to about 80%, or about 30% to about 80%, or about 40% to about 80%, or about 45% to about 80%, or about 50% to about 80%, or about 55% to about 80%, or about 60% to about 80%, or about 65% to about 80%, or about 70% to about 80%, or about 75% to about 80%,The deposited material, such as a filtration material, which may be a porous inorganic layer, has an average thickness of 0.5 μm to 50 μm, or 0.5 μm to 45 μm, or 0.5 μm to 40 μm, or 0.5 μm to 35 μm, or 0.5 μm to 30 μm, or 0.5 μm to 25 μm, or 0.5 μm to 20 μm, or 0.5 μm to 15 μm, or 0.5 μm to 10 μm.

[0008] Additional features and advantages will be set forth in the following detailed description, and in part will become readily apparent to those skilled in the art from that description, or may be learned by practicing the embodiments described herein, including the following detailed description, claims, and accompanying drawings.

[0009] It should be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments described herein and, together with the description, serve to explain the principles and operation of the claimed subject matter. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating a honeycomb body according to an embodiment disclosed and described herein. [Figure 2] 1 is a schematic diagram illustrating a particulate filter according to an embodiment disclosed and described herein. [Figure 3] FIG. 3 is a cross-sectional view of the particulate filter shown in FIG. 2. [Figure 4] 1 is a schematic diagram illustrating a wall of a honeycomb body with soot loading according to embodiments disclosed and described herein. [Figure 5] 1 is a flow chart illustrating an exemplary embodiment of a process for forming a material, which may be a porous inorganic layer, according to embodiments disclosed herein. [Figure 6A] FIG. 1 is a schematic diagram illustrating an apparatus for depositing a material, which may be a porous inorganic layer, according to embodiments disclosed herein. [Figure 6B] FIG. 1 is a schematic diagram illustrating an apparatus for depositing a material, which may be a porous inorganic layer, according to embodiments disclosed herein. [Figure 6C] FIG. 1 is a schematic diagram illustrating an apparatus for depositing a material, which may be a porous inorganic layer, according to embodiments disclosed herein. [Figure 6D] FIG. 1 is a schematic diagram illustrating an apparatus for depositing a material, which may be a porous inorganic layer, according to embodiments disclosed herein. [Figure 7] 1 is an SEM photograph of Al2O3 aggregates or agglomerates according to embodiments disclosed and described herein. [Figure 8A] 1 is an SEM photograph of a honeycomb body having material formed on the wall 10% deep from the inlet wall surface. [Figure 8B] 1 is an SEM photograph of a honeycomb body having material formed on the wall 50% deep from the inlet wall surface. [Figure 8C] 1 is an SEM photograph of a honeycomb body having material formed on the wall 90% of the way from the inlet wall surface. [Figure 8D] 1 is an SEM photograph of a cross section of a honeycomb body having material formed on the wall at a depth of 10% from the inlet wall surface. [Figure 8E] 1 is an SEM photograph of a cross section of a honeycomb body having material formed on the wall 50% deep from the inlet wall surface. [Figure 8F] 1 is an SEM photograph of a cross section of a honeycomb body having material formed on the wall 90% of the way from the inlet wall surface. [Figure 9] 10 is a graph showing filtration efficiency comparing an uncoated honeycomb body to a honeycomb body having a material formed on the wall according to embodiments disclosed and described herein. [Figure 10] 1 is a graph showing back pressure versus flow rate for an uncoated honeycomb body compared to two different honeycomb bodies having materials formed on the walls according to embodiments disclosed and described herein. [Figure 11]10 is a graph illustrating backpressure versus soot loading for an uncoated honeycomb body compared to a honeycomb body having a material formed on the wall according to embodiments disclosed and described herein. [Figure 12A] 1 is an SEM photograph of a honeycomb body having material formed on the wall 10% deep from the inlet wall surface. [Figure 12B] 1 is an SEM photograph of a honeycomb body having material formed on the wall 50% deep from the inlet wall surface. [Figure 12C] 1 is an SEM photograph of a honeycomb body having material formed on the wall 90% of the way from the inlet wall surface. [Figure 12D] 1 is an SEM photograph of a cross section of a honeycomb body having material formed on the wall at a depth of 10% from the inlet wall surface. [Figure 12E] 1 is an SEM photograph of a cross section of a honeycomb body having material formed on the wall 50% deep from the inlet wall surface. [Figure 12F] 1 is an SEM photograph of a cross section of a honeycomb body having material formed on the wall 90% of the way from the inlet wall surface. [Figure 13A] 1 is an SEM photograph of a honeycomb body having material formed on the wall of Example 4 after testing as described in the Examples, taken at a depth of 10% from the inlet wall surface. [Figure 13B] 1 is an SEM photograph of a honeycomb body having material formed on the wall of Example 4 after testing as described in the Examples, taken at a depth of 50% from the inlet wall surface. [Figure 13C] 1 is an SEM photograph of a honeycomb body having material formed on the wall of Example 4 after testing as described in the Examples, taken 90% of the way down from the inlet wall surface. [Figure 14A] 1 is an SEM photograph of primary particles measured for circularity. [Figure 14B] 14B is a table of data from FIG. 14A. [Figure 15A] 1 is an SEM photograph of agglomerates measured for circularity. [Figure 15B] 15B is a table of the data from FIG. 15A. DETAILED DESCRIPTION OF THE INVENTION

[0011] Reference will now be made in detail to embodiments of honeycomb bodies, including porous honeycomb bodies having a porous inorganic layer thereon, these embodiments being illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0012] Aspects of the present disclosure relate to articles, such as ceramic articles, and methods for their manufacture and use. In some embodiments, the ceramic article has a honeycomb body comprising a porous ceramic honeycomb structure with porous walls having wall surfaces defining a plurality of internal channels.

[0013] In some embodiments, the porous ceramic walls include a material, such as a filtration material, which may include a porous inorganic layer disposed on one or more surfaces of the wall. In some embodiments, the filtration material includes one or more inorganic materials, such as one or more ceramic materials or refractory materials. In some embodiments, the filtration material is disposed on the walls to provide improved filtration efficiency both locally at the walls and globally through the honeycomb body during at least the initial use of the honeycomb body as a filter after the honeycomb body is clean or regenerated, such as before significant ash and / or soot buildup occurs inside the honeycomb body after extended use of the honeycomb body as a filter.

[0014] In one aspect, the filtration material is present as a layer disposed on one or more surfaces of the honeycomb structure walls. In some embodiments, the layer is porous to allow gas flow through the walls. In some embodiments, the layer is present as a continuous coating over at least a portion or the entire surface of one or more walls. In some embodiments of this aspect, the filtration material is a flame-deposited filtration material.

[0015] In another aspect, the filtration material is present as a plurality of discrete regions of filtration material disposed on the surface of one or more of the walls of the honeycomb structure. The filtration material may partially block some of the pores of the porous walls, but still allow gas flow through the walls. In some embodiments of this aspect, the filtration material is an aerosol-deposited filtration material. In some preferred embodiments, the filtration material comprises a plurality of inorganic particle agglomerates made of an inorganic material, a ceramic material, or a refractory material. In some embodiments, the agglomerates are porous, thereby allowing gas to flow through the agglomerates.

[0016] In some embodiments, the honeycomb body comprises a porous ceramic honeycomb body having a first end, a second end, and a plurality of walls having wall surfaces defining a plurality of interior channels. A deposited material, such as a filtration material, which may be a porous inorganic layer, is disposed on one or more of the wall surfaces of the honeycomb body. The deposited material, such as a filtration material, which may be a porous inorganic layer, is about 20% to about 95%, or about 25% to about 95%, or about 30% to about 95%, or about 40% to about 95%, or about 45% to about 95%, or about 50% to about 95%, or about 55% to about 95%, or about 60% to about 95%, or about 65% to about 95%, or about 70% to about 95%, or about 75% to about 95%, or about 80% to about 95%, or about 85% to about 95%, or about 30% to about 95%, or about 40% to about 95%, or about 45% to about 95%, or about 50% to about 95%, or about 55% to about 95%, or about 60% to about 95%, or about 65% to about 95%, or about 70% to about 95%, or about 75% to about 95%, or about 80% to about 95%, or about 85% to about 95%, or about 20% to about 90%, or about 25% to about 90%, or about 30% to about 90%, or about 40% to about 90%, or about 45% to about 90%, or about 50% to about 90%, or about 55% to about 90%, or about 60 % to about 90%, or about 65% to about 90%, or about 70% to about 90%, or about 75% to about 90%, or about 80% to about 90%, or about 85% to about 90%, or about 20% to about 85%, or about 25% to about 85%, or about 30% to about 85%, or about 40% to about 85%, or about 45% to about 85%, or about 50% to about 85%, or about 55% to about 85%, or about 60% to about 85%, or about 65% to about 85%, or about 70% to about 85%, or about 75% to about 85% , or about 80% to about 85%, or about 20% to about 80%, or about 25% to about 80%, or about 30% to about 80%, or about 40% to about 80%, or about 45% to about 80%, or about 50% to about 80%, or about 55% to about 80%, or about 60% to about 80%, or about 65% to about 80%, or about 70% to about 80%, or about 75% to about 80%, and the deposited material, such as a filtration material, which may be a porous inorganic layer, has a porosity in the range of 0.5 μm or more and 50 μm or less, or 0.The honeycomb body has an average thickness of 5 μm to 45 μm, 0.5 μm to 40 μm, or 0.5 μm to 35 μm, or 0.5 μm to 30 μm, 0.5 μm to 25 μm, or 0.5 μm to 20 μm, or 0.5 μm to 15 μm, or 0.5 μm to 10 μm. Various embodiments of honeycomb bodies and methods for forming such honeycomb bodies are described herein with particular reference to the accompanying drawings.

[0017] The material comprises a filtration material in some embodiments, and an inorganic layer in some embodiments. According to one or more embodiments, the inorganic layer provided herein comprises a discontinuous layer formed from the inlet end to the outlet end, comprising disconnected, discrete patches of material or filtration material, and a binder comprised of primary particles within substantially spherical secondary aggregate particles or agglomerates. In one or more embodiments, the primary particles are non-spherical. In one or more embodiments, "substantially spherical" refers to agglomerates having a cross-sectional circularity within a range of about 0.8 to about 1 or about 0.9 to about 1, where 1 represents a perfect circle. In one or more embodiments, 75% of the primary particles deposited on the honeycomb body have a circularity of less than 0.8. In one or more embodiments, the aggregate particles or agglomerates deposited on the honeycomb body have an average circularity of greater than 0.9, greater than 0.95, greater than 0.96, greater than 0.97, greater than 0.98, or greater than 0.99.

[0018] Circularity can be measured using a scanning electron microscope (SEM). The term "cross-sectional circularity (or simply circularity)" is a value expressed using the formula shown below. A circle with a circularity of 1 is a perfect circle.

[0019] Circularity = (4π x cross-sectional area) / (perimeter of cross section) 2 .

[0020] In one or more embodiments, the "filtration material" provides the honeycomb body with improved filtration efficiency, both locally at and through the walls, and generally through the honeycomb body. In one or more embodiments, the "filtration material" does not react with components of the gaseous mixture of the exhaust stream and is therefore not considered catalytically active.

[0021] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include embodiments having plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the content clearly dictates otherwise.

[0022] As used herein, the words "have," "having," "include," "including," "comprise," "comprising," and the like are used in their open-ended sense and generally mean "including, but not limited to."

[0023] As referred to herein, a honeycomb body is a formed ceramic honeycomb structure of intersecting walls forming cells that define channels. The ceramic honeycomb structure may be formed, extruded, or molded and may be of any shape or size. For example, the ceramic honeycomb structure may be a filter body formed from cordierite or other suitable ceramic material.

[0024] As referred to herein, a honeycomb body may also be defined as a formed ceramic honeycomb structure having at least one layer applied to the wall surface of the honeycomb structure configured to filter particulate matter from a gas stream. There may be more than one layer applied to the same location on the honeycomb structure. The layer may comprise inorganic material, organic material, or both inorganic and organic materials. For example, in one or more embodiments, the honeycomb body may be formed from cordierite or other ceramic material and may have a porous inorganic layer applied to the surface of the cordierite honeycomb structure.

[0025] As used herein, "green" or "green ceramic" are used interchangeably unless otherwise specified and refer to unsintered material.

[0026] The honeycomb body of one or more embodiments may include a honeycomb structure and a deposited material, such as a filtration material, which may be a porous inorganic layer, disposed on one or more walls of the honeycomb structure. In some embodiments, the deposited material, such as a filtration material, which may be a porous inorganic layer, is applied to a surface of a wall present within the honeycomb structure, the wall having a surface that defines a plurality of internal channels.

[0027] The internal channels, when present, may have a variety of cross-sectional shapes, such as circular, oval, triangular, square, pentagonal, hexagonal, or a tessellated combination of any of these, and may be arranged in any suitable geometric configuration. The internal channels, when present, may be discrete or intersecting and may extend through the honeycomb body from a first end of the honeycomb body to a second end of the honeycomb body opposite the first end.

[0028] 1, there is shown a honeycomb body 100 according to one or more embodiments shown and described herein. The honeycomb body 100, in embodiments, may comprise a plurality of walls 115 that define a plurality of interior channels 110. The plurality of interior channels 110 and intersecting channel walls 115 extend between a first end 105, which may be an inlet end, and a second end 135, which may be an outlet end, of the honeycomb body.

[0029] In one or more embodiments, the honeycomb body may be formed from cordierite, aluminum titanate, enstatite, mullite, forsterite, corundum (SiC), spinel, sapphirine, and periclase. Generally, cordierite has the formula (Mg,Fe)Al(SiAlO 18 ) In some embodiments, the pore size of the ceramic material may be controlled, the porosity of the ceramic material may be controlled, and the pore size distribution of the ceramic material may be controlled, for example, by varying the particle size of the ceramic raw materials. Additionally, a pore former may be included in the ceramic batch used to form the honeycomb body.

[0030] In some embodiments, the walls of a honeycomb body may have an average thickness of 25 μm to 250 μm, such as 45 μm to 230 μm, 65 μm to 210 μm, 65 μm to 190 μm, or 85 μm to 170 μm. The walls of a honeycomb body may be described as having a base portion consisting of a bulk portion (also referred to herein as bulk) and a surface portion (also referred to herein as surface). The surface portion of the wall extends into the wall from the surface of the honeycomb body wall toward the bulk portion of the honeycomb body. The surface portion may extend to a depth of 0 to about 10 μm into the base portion of the honeycomb body wall. In some embodiments, the surface portion may extend about 5 μm, about 7 μm, or about 9 μm (i.e., a depth of 0) into the base portion of the wall. The bulk portion of a honeycomb body is equal to the wall thickness minus the surface portion. Therefore, the bulk portion of a honeycomb body can be determined by the following formula: ttotal -2t surface (In the formula, t total is the total thickness of the wall, and t surface is the thickness of the wall surface).

[0031] In one or more embodiments, the bulk of the honeycomb body (before any material or filtration material or layer is applied) has a bulk average pore size of from 7 μm to 25 μm, such as from 12 μm to 22 μm, or from 12 μm to 18 μm. For example, in some embodiments, the bulk of the honeycomb body may have a bulk average pore size of about 10 μm, about 11 μm, about 12 μm, about 13 μm, about 14 μm, about 15 μm, about 16 μm, about 17 μm, about 18 μm, about 19 μm, or about 20 μm. Generally, the pore sizes of any given material exist in a statistical distribution. Thus, the term "average pore size" or "d" (before any material or filtration material or layer is applied) is used. 50 The term "length measurement" refers to the length measurement above which 50% of the pores have a pore size and below which the remaining 50% of the pores have a pore size based on the statistical distribution of all pores. Porosity in ceramic bodies can be created by at least one of the following: (1) inorganic batch material particle size and size distribution, (2) furnace / heat treatment firing time and temperature schedule, (3) furnace atmosphere (e.g., low or high oxygen content and / or water content), and (4) pore formers, such as polymers and polymer particles, starch, wood flour, hollow inorganic particles, and / or graphite / carbon particles.

[0032] In certain embodiments, the average pore size (d 50 ) is in the range of 10 μm to about 16 μm, for example, 13 to 14 μm, and d 10 refers to the length measurement above which 90% of the pores are sized and below which the remaining 10% of the pores are sized based on a statistical distribution of all pores, and is approximately 7 μm. 90refers to the length measurement above which 10% of the pores in the bulk of a honeycomb body (before any material or filtration material or layer is applied) have a pore size and below which the remaining 90% of the pores have a pore size, based on a statistical distribution of all pores, and is approximately 30 μm. In certain embodiments, the average diameter (D 50 ) is about 2 μm. In certain embodiments, the agglomerate average size D 50 and the average wall pore size d of the bulk honeycomb body 50 is the average agglomerate size D 50 vs. average wall pore size d of bulk honeycomb body 50 It has been found that excellent filtration efficiency results and low pressure drop results are obtained when the ratio of agglomerates D to D is in the range of 5:1 to 16:1. Furthermore, in certain embodiments, the average agglomerate size D (before any material or filtration material or layer is applied) 50 vs. average wall pore size d of the honeycomb bulk 50 The ratio is in the range of 6:1 to 16:1, 7:1 to 16:1, 8:1 to 16:1, 9:1 to 16:1, 10:1 to 16:1, 11:1 to 16:1 or 12:1 to 6:1, which gives excellent filtration efficiency results and low pressure drop results.

[0033] In some embodiments, the bulk of the honeycomb body, not considering coatings, may have a bulk porosity of 50% or more and 75% or less as measured by mercury intrusion porosimetry. Other methods for measuring porosity include scanning electron microscopy (SEM) and X-ray tomography, two methods particularly useful for measuring surface and bulk porosity independently of one another. In one or more embodiments, the bulk porosity of the honeycomb body may be, for example, in the range of about 50% to about 75%, about 50% to about 70%, about 50% to about 65%, about 50% to about 60%, about 50% to about 58%, about 50% to about 56%, or about 50% to about 54%.

[0034] In one or more embodiments, the surface portion of the honeycomb body has a surface average pore size of from 7 μm to 20 μm, such as from 8 μm to 15 μm, or from 10 μm to 14 μm. For example, in some embodiments, the surface of the honeycomb body may have a surface average pore size of about 8 μm, about 9 μm, about 10 μm, about 11 μm, about 12 μm, about 13 μm, about 14 μm, or about 15 μm.

[0035] In some embodiments, the surface of the honeycomb body may have a surface porosity of 35% or more and 75% or less, prior to application of the layer, as measured by mercury intrusion porosimetry, SEM, or X-ray tomography. In one or more embodiments, the surface porosity of the honeycomb body may be less than 65%, such as less than 60%, less than 55%, less than 50%, less than 48%, less than 46%, less than 44%, less than 42%, less than 40%, less than 48%, or less than 36%.

[0036] 2, there is shown schematically a honeycomb body in the form of a particulate filter 200. The particulate filter 200 may be used as a wall-flow filter to filter particulate matter from an exhaust gas stream 250, such as an exhaust gas stream emitted from a gasoline engine (in which case the particulate filter 200 is a gasoline particulate filter). The particulate filter 200 generally has an overall length L (shown in FIG. 3) of 100 mm. a The particulate filter 200 includes a honeycomb body having a plurality of channels 201 or cells extending between an inlet end 202 and an outlet end 204 that define a plurality of intersecting channel walls 206. The channels 201 of the particulate filter 200 are formed by, and at least partially defined by, a plurality of intersecting channel walls 206 that extend from the inlet end 202 to the outlet end 204. The particulate filter 200 may include a skin layer 205 that surrounds the plurality of channels 201. The skin layer 205 may be extruded during the formation of the channel walls 206, or may be formed as a subsequently applied skin layer, such as by applying a skinning cement to the outer periphery of the channels in a later process.

[0037] An axial cross section of the particulate filter 200 of FIG. 2 is shown in FIG. 3. In some embodiments, certain channels are designated as inlet channels 208, and certain other channels are designated as outlet channels 210. In some embodiments of the particulate filter 200, at least a first set of channels may be plugged with plugs 212. Generally, the plugs 212 are arranged proximate to the ends (i.e., the inlet end or the outlet end) of the channels 201. The plugs are generally arranged in a predefined pattern, such as the checkerboard pattern shown in FIG. 2, with every other channel being plugged at its end. As shown in FIG. 3, the inlet channels 208 may be plugged at or near the outlet end 204, and the outlet channels 210 may be plugged at or near the inlet end 202 on channels that do not correspond to the inlet channels. Thus, each cell may be plugged only at or near one end of the particulate filter.

[0038] 2 generally depicts a checkerboard plugging pattern, it should be understood that alternative plugging patterns may be used in the porous ceramic honeycomb article. In the embodiments described herein, the particulate filter 200 has a plugging density of up to about 600 channels per square inch (cpsi) (about 93.0 channels / cm 2 For example, in some embodiments, the particulate filter 200 may be formed with a channel density of about 100 cpsi to about 600 cpsi (about 15.5 channels / cm 2 ~approximately 93.0 channels / cm 2 In some other embodiments, the particulate filter 200 may have a channel density in the range of about 100 cpsi to about 400 cpsi (about 15.5 channels / cm). 2 ~approximately 62.0 channels / cm 2 ) or even about 200 cpsi to about 300 cpsi (about 31.0 channels / cm 2 ~approximately 46.5 channels / cm 2 ) may have a channel density in the range of .

[0039] In the embodiments described herein, the channel walls 206 of the particulate filter 200 may have a thickness greater than about 4 mils (101.6 μm). For example, in some embodiments, the thickness of the channel walls 206 may be in the range of about 4 mils (about 0.1 mm) up to about 30 mils (762 μm). In some other embodiments, the thickness of the channel walls 206 may be in the range of about 7 mils (177.8 μm) to about 20 mils (508 μm).

[0040] In some embodiments of the particulate filter 200 described herein, the channel walls 206 of the particulate filter 200 may have an uncoated open porosity (i.e., porosity before any coating is applied to the honeycomb body) %P≧35% before the application of any coating to the particulate filter 200. In some embodiments, the uncoated open porosity of the channel walls 206 may be such that 40%≦%P≦75%. In other embodiments, the uncoated open porosity of the channel walls 206 may be such that 45%≦%P≦75%, 50%≦%P≦75%, 55%≦%P≦75%, 60%≦%P≦75%, 45%≦%P≦70%, 50%≦%P≦70%, 55%≦%P≦70%, or 60%≦%P≦70%.

[0041] Furthermore, in some embodiments, the channel walls 206 of the particulate filter 200 are formed so that the pore distribution within the channel walls 206 has an average pore size of 30 μm or less before the application of any coating (i.e., uncoated). For example, in some embodiments, the average pore size may be 8 μm or more and 30 μm or less. In other embodiments, the average pore size may be 10 μm or more and 30 μm or less. In other embodiments, the average pore size may be 10 μm or more and 25 μm or less. In some embodiments, particulate filters produced with an average pore size greater than about 30 μm have reduced filtration efficiency, while particulate filters produced with an average pore size less than about 8 μm may have difficulty penetrating the pores with a washcoat containing a catalyst. Therefore, in some embodiments, it is desirable to maintain the average pore size of the channel walls within a range of about 8 μm to about 30 μm, for example, a range of 10 μm to about 20 μm.

[0042] In one or more embodiments described herein, the honeycomb body of the particulate filter 200 is formed from a metal or ceramic material, such as cordierite, silicon carbide, aluminum oxide, aluminum titanate, or any other ceramic material suitable for use in high-temperature particulate filtration applications. For example, the particulate filter 200 may be formed from cordierite by mixing a batch of ceramic precursor materials, which may include building blocks suitable for producing ceramic articles containing primarily the cordierite crystalline phase. Building blocks suitable for cordierite formation generally include a combination of inorganic components, including talc, a silica-producing source, and an alumina-producing source. The batch composition may additionally include clay, such as kaolin clay. The cordierite precursor batch composition may also include organic components, such as an organic pore former, which is added to the batch mixture to achieve a desired pore size distribution. For example, the batch composition may include starch suitable for use as a pore former and / or other processing aid. Alternatively, the build materials may include one or more cordierite powders and organic pore former materials suitable for forming a sintered cordierite honeycomb structure upon firing.

[0043] The batch composition may additionally include one or more processing aids, such as a binder, and a liquid vehicle, such as water or a suitable solvent. Processing aids are added to the batch mixture to plasticize the batch mixture and generally to improve processing, shorten drying time, reduce cracking during firing, and / or help produce desired properties in the honeycomb body. For example, the binder may include an organic binder. Suitable organic binders include water-soluble cellulose ether binders, such as methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose derivatives, hydroxyethyl acrylate, polyvinyl alcohol, and / or any combination thereof. The incorporation of an organic binder into the plasticized batch composition allows the plasticized batch composition to be easily extruded. In some embodiments, the batch composition may include one or more optional forming or processing aids, such as a lubricant that aids in the extrusion of the plasticized batch mixture. Exemplary lubricants may include tall oil, sodium stearate, or other suitable lubricants.

[0044] After the batch of ceramic precursor material is mixed with appropriate processing aids, the batch of ceramic precursor material is extruded and dried to form a green honeycomb body having an inlet end and an outlet end with a plurality of channel walls extending between the inlet end and the outlet end. The green honeycomb body is then fired according to a firing schedule suitable for producing a fired honeycomb body. At least a first set of the channels of the fired honeycomb body are then plugged with a ceramic plugging composition in a predefined plugging pattern, and the fired honeycomb body is fired again to ceramify the plugs and secure them within the channels.

[0045] In various embodiments, the honeycomb body is configured to filter particulate matter from a gas stream, such as an exhaust gas stream from a gasoline engine. Accordingly, the average pore size, porosity, geometry, and other design aspects of both the bulk and surface of the honeycomb body are selected with these filtration requirements of the honeycomb body in mind. By way of example, and as shown in the embodiment of FIG. 4 , the wall 310 of a honeycomb body 300, which may be in the form of the particulate filter shown in FIGS. 2 and 3 , has a layer 320 disposed thereon, which in some embodiments is sintered or bonded by heat treatment. The layer 320 is deposited on the wall 310 of the honeycomb body 300 and may include particles 325 that help prevent particulate matter, such as soot and ash, from exiting the honeycomb body with the gas stream 330 and help prevent the particulate matter from clogging the base portion of the wall 310 of the honeycomb body 300. In this manner, and according to embodiments, layer 320 can function as a primary filtering component, while the base portion of the honeycomb body can otherwise be configured to minimize pressure loss, for example, compared to a conventional honeycomb body that does not include such a layer. As described in further detail herein, the layer can be formed by a suitable method, such as an aerosol deposition method. Aerosol deposition allows for the formation of a thin, porous layer on at least some of the surfaces of the honeycomb body's walls. An advantage of the aerosol deposition method according to one or more embodiments is that honeycomb bodies can be produced more economically than with other techniques, such as flame deposition processes. However, several difficulties have been encountered using the aerosol deposition method. The present specification provides a manufacturing method that avoids the difficulties associated with the aerosol deposition process. According to one or more embodiments, the aerosol deposition process results in a unique primary particle morphology, which is described further below.

[0046] According to one or more embodiments, a process is provided that includes generating an aerosol with a binder process, and the aerosol is deposited on a honeycomb body to provide a high filtration efficiency material, which may be an inorganic layer, on the honeycomb body for the purpose of providing a gasoline particulate filter. According to one or more embodiments, performance is greater than 90% filtration efficiency at the cost of less than 10% pressure loss compared to an uncoated filter. According to one or more embodiments, the process can include the steps of solution preparation, atomization, drying, and deposition and curing of the material on the wall of the wall-flow filter. It has been discovered that aerosol deposition with a binder can form materials, such as porous inorganic layers, with high mechanical integrity without any sintering step (e.g., heating to temperatures above 1000°C). In certain embodiments, the filtration efficiency of the material, which may be an inorganic layer, at a soot loading of 0.01 g / L was increased from 78.4% to 97.6% at the cost of less than 10% pressure loss.

[0047] According to one or more embodiments, an exemplary process flow includes solution preparation, atomization, drying, deposition on a honeycomb body, and curing. Each of these steps will now be discussed in more detail according to exemplary embodiments.

[0048] Solution preparation Commercially available inorganic particles were used as raw materials to generate a suspension for forming an inorganic material, which may be the inorganic layer. According to one or more embodiments, the particles are selected from Al2O3, SiO2, TiO2, CeO2, ZrO2, SiC, MgO, and combinations thereof. In some embodiments, the suspension is aqueous-based, while in other embodiments, the suspension is organic-based, for example, an alcohol such as ethanol or methanol.

[0049] In one or more embodiments, the particles have an average primary particle size in the range of about 10 nm to about 4 μm, about 20 nm to about 3 μm, or about 50 nm to about 2 μm, or about 50 nm to about 900 nm, or about 50 nm to about 600 nm. In certain embodiments, the average primary particle size is in the range of about 100 nm to about 200 nm, e.g., 150 nm. The average primary particle size can be determined as a calculation from the BET surface area of ​​the aerosol particles, which in some embodiments is currently less than 10 m 2 / g.

[0050] In one or more embodiments, the primary particles comprise oxide particles, for example ceramic particles such as Al2O3, SiO2, MgO, CeO2, ZrO2, CaO, TiO2, cordierite, mullite, SiC, aluminum titanate, and mixtures thereof.

[0051] The solution is produced using a solvent, which is added as needed to dilute the suspension. If the droplets produced by atomization have a similar size, reducing the solids content in the solution can also proportionally reduce the aggregate size. The solvent should be miscible with the suspension and be a solvent for the binder and other ingredients.

[0052] Binders, including inorganic binders, are added to strengthen the deposited material to provide mechanical integrity. The binder provides interparticle bonding strength at high temperatures (>500°C). The starting material can be organic. After exposure to temperatures above about 150°C, the organic starting material will decompose or react with moisture and oxygen in the air, and the final deposited material composition may include Al2O3, SiO2, MgO, CeO2, ZrO2, CaO, TiO2, cordierite, mullite, SiC, aluminum titanate, and mixtures thereof. Examples of suitable binders are Dowsil™ US-CF-2405 and Dowsil™ US-CF-2403, both available from The Dow Chemical Company.

[0053] A catalyst can be added to accelerate the curing reaction of the binder. The catalyst used in Dowsil™ US-CF-2405 to accelerate the curing reaction is titanium butoxide.

[0054] atomization The prepared mixture is atomized into fine droplets by high-pressure gas passing through a nozzle. An example nozzle is a 1 / 4J-SS+SU11-SS nozzle manufactured by Spraying Systems Co. equipped with a fluid cap 2050 and an air cap 67147. The atomizing gas pressure is in the range of 20 psi to 150 psi (approximately 140 kPa to approximately 1.03 MPa). The liquid pressure is in the range of 1 to 100 psi (approximately 7 to approximately 689 kPa). In one or more embodiments, the average droplet size is in the range of 1 μm to 40 μm, e.g., 5 μm to 10 μm. The droplet size can be adjusted by adjusting the solution surface tension, solution viscosity, solution density, gas flow rate, gas pressure, liquid flow rate, liquid pressure, and nozzle design. In one or more embodiments, the atomizing gas comprises air, nitrogen, or a mixture thereof. In certain embodiments, the atomizing gas and device are air-free.

[0055] Drying To avoid the effects of liquid capillary forces, which can produce uneven materials in the inorganic layer and result in high pressure losses, the droplets are dried in the deposition chamber to form dry solid agglomerate particles. The solvent evaporates and passes through the honeycomb body in the gas phase; therefore, liquid solvent residue or condensation is minimized during material deposition. When the inorganic material is transported into the honeycomb body by gas flow, the residue in the inorganic material should be less than 10% by weight. All others should evaporate and form the gas phase during the drying step. Liquid residue includes solvents in solution (e.g., ethanol) and water condensed from the gas phase. Binders are not considered liquid residues, even if they are in a liquid state before curing.

[0056] Deposition in honeycomb body The secondary agglomerate particles or agglomerates of primary particles are transported by the gas flow and are deposited on the inlet wall surface of the honeycomb body as air passes through the honeycomb body. The flow can be driven by a fan, blower, or vacuum pump.

[0057] In one or more embodiments, the average diameter of the secondary aggregate particles or agglomerates is within the range of 300 nm to 10 μm, 300 nm to 8 μm, 300 nm to 7 μm, 300 nm to 6 μm, 300 nm to 5 μm, 300 nm to 4 μm, or 300 nm to 3 μm. In certain embodiments, the average diameter of the secondary aggregate particles or agglomerates is about 2 μm. The average diameter of the secondary aggregate particles or agglomerates can be measured by scanning electron microscopy.

[0058] In one or more embodiments, the average diameter of the secondary aggregate particles or agglomerates is in the range of 300 nm to 10 μm, 300 nm to 8 μm, 300 nm to 7 μm, 300 nm to 6 μm, 300 nm to 5 μm, 300 nm to 4 μm, or 300 nm to 3 μm, and the ratio is from about 2:1 to about 10:1, from about 2:1 to about 9:1, from about 2:1 to about 8:1, from about 2:1 to about 7:1, from about 2:1 to about 6:1, from about 2:1 to about 5:1, from about 3:1 to about 10:1, from about 3:1 to about 9:1 , about 3:1 to about 8:1, about 3:1 to about 7:1, about 3:1 to about 6:1, about 3:1 to about 5:1, about 4:1 to about 10:1, about 4:1 to about 9:1, about 4:1 to about 8:1, about 4:1 to about 7:1, about 4:1 to about 6:1, about 4:1 to about 5:1, about 5:1 to about 10:1, about 5:1 to about 9:1, about 5:1 to about 8:1, about 5:1 to about 7:1, or about 5:1 to about 6:1.

[0059] hardening Post-treatments are used to cure binders according to one or more embodiments. Depending on the binder composition, the curing conditions vary. According to some embodiments, a low-temperature cure reaction is utilized, for example, at temperatures of 100°C or less. In some embodiments, curing can be completed in vehicle exhaust gases having temperatures of 950°C or less. A calcination process is optional and can be performed at temperatures of 650°C or less.

[0060] FIG. 5 is a flowchart illustrating an exemplary process flow according to certain embodiments.

[0061] An example of an apparatus used for the deposition of the aerosol with binder process is shown in Figures 6A-D.

[0062] FIG. 6A illustrates a pressure control system that can be used to control agglomerate size during the formation of agglomerates deposited on a gasoline particulate filter, labeled GPF in FIGS. 6A-D. In FIG. 6A, a pressure controller is in communication with a delivery conduit, such as a tube or pipe, into which a suspension of primary particles in a liquid is introduced and then flowed to a nozzle. In a separate line, an atomizing gas, which may be any suitable gas, such as nitrogen or air, is flowed to the nozzle to atomize the suspension within a suitable nozzle, as described further below. The GPF is placed within an enclosure, as shown in FIG. 6A, and the atomized suspension is directed through the GPF while gas is flowed into the enclosure from one end. Heaters H1 and H2 heat the gas flowed from one end of the enclosure, and pressure gauges, labeled PG in FIGS. 6A-B, measure the pressure upstream and downstream of the GPF. A fan is placed within the enclosure downstream of the GPF, as shown in FIG. 6A, and is connected by a conduit, and a flow measurement device monitors the flow rate. According to one or more embodiments, control of the pressure of the suspension delivered to the nozzle can control the size of the agglomerates formed during the process. The atomized suspension is deposited onto one or more walls of the GPF as a material, such as a filtration material, which may be an inorganic layer composed of primary particles formed into agglomerates.

[0063] FIG. 6B illustrates an alternative system using flow control to control agglomerate size. As shown in FIG. 6B, the flow control includes an injector pump, which delivers a suspension of primary particles in a liquid through a conduit to a nozzle, as shown. An atomizing gas is passed through a separate conduit, as shown in FIG. 6B, and the nozzle atomizes the suspension, which is delivered to a GPF, as shown. Pressure gauges, labeled PG in FIGS. 6A-B, measure the pressure upstream and downstream of the GPF. Heaters H1 and H2, which may be resistance heaters or other suitable heaters, heat the gas delivered from a first end of the enclosure containing the GPF. A fan, as shown in FIG. 6A, is connected to a conduit in fluid communication with the enclosure containing the GPF, and a flow monitor, labeled FLOW, monitors the flow rate provided by the fan. The atomized suspension is deposited on one or more walls of the GPF as a material, such as a filtration material, which may be an inorganic layer formed from the primary particles into agglomerates.

[0064] FIG. 6C shows another embodiment of a system for atomizing a suspension for depositing material onto a GPF. Nitrogen gas or other suitable process gas is delivered through a conduit monitored by a pressure regulator, and a flow meter monitors the flow rate to the nozzle. Nitrogen gas or any other suitable process gas is flowed through a separate conduit, and a pressure regulator PR monitors the pressure. A suspension of primary particles in a liquid is delivered to the nozzle, and the flow rate is measured by a flow meter FM. The gas is delivered to an enclosure with a heater, as shown, upstream of the GPF within the enclosure. A pressure meter measures the pressure upstream and downstream of the GPF. A blower or fan is in fluid communication with the enclosure containing the GPF through a conduit, and a flow meter measures the flow rate within this conduit. The atomized suspension is deposited on one or more walls of the GPF as a material, such as a filtration material, which may be an inorganic layer formed into agglomerates, consisting of primary particles. It should be understood that in FIG. 6C, the suspension is delivered in a downward direction. The atomized suspension is deposited onto one or more walls of the GPF as a material, such as a filtering material, which may be an inorganic layer made up of primary particles formed into agglomerates.

[0065] In Figure 6D, the system is configured similarly to the system shown in Figure 6C, except that the flow of suspension is delivered upward through the GPF as shown, and a blower connected to the enclosure containing the GPF directs gas downstream of the GPF.

[0066] In the flow chart of FIG. 5 and the apparatus shown in FIGS. 6A-D, the diameter and length of the cordierite honeycomb filter used were 4.055 inches (10.3 cm) and 5.47 inches (13.9 cm). 2 ) and wall thickness is 200 (approximately 31.0 cells / cm 2 ) and 8 mil (approximately 0.2 mm). The average pore size was 14 μm.

[0067] Particles prepared from Al2O3 with an average primary particle size of 150 nm were used to prepare a suspension using ethanol (30 mass% solids, Beijing Dk Nano Technology Co. Ltd.). The suspension was diluted to 11 mass% with ethanol (AR, Sinopharm Group Co. LTD). Dowsil™ US-CF-2405 and TnBT were added as binders and curing reaction catalysts. The ratio of binder to Al2O3 was 5 mass%. The ratio of catalyst to binder was 1 mass%.

[0068] A two-phase fluid nozzle (1 / 4J-SS+SU11-SS, Spraying Systems Co.) was used to atomize the solution. The atomizing gas was nitrogen at 116 psi (approximately 800 kPa), and the liquid pressure was 78 psi (approximately 540 kPa). The liquid atomization rate was approximately 32 ml / min.

[0069] The droplets were dried in a deposition chamber shown in Figures 6A and 6B. Figure 6A shows the pressure control system utilized in the example. Figure 6B shows the flow control system not used in the example. The gas flow and droplets were heated by surrounding heaters, and the set temperatures of zones T1-2 and T1-1 were 350°C and 200°C.

[0070] The flow was driven by a 2518 RPM (TBR R11Q CL.HP manufactured by Twin City Fan (Shanghai) Co. Ltd.). The total flow rate was 20 Nm 3 / h (standard cubic meters per hour). Additional air was drawn into the system to achieve the required total flow rate. Deposition onto the honeycomb filter was carried out for 173 seconds, with a final Al2O3 loading of 5.6 g / L.

[0071] After deposition, the parts were cured within a temperature range of 40°C to 200°C for 10 minutes to 48 hours.

[0072] Figure 6A shows a schematic of the deposition system. Components included a solution container, with liquid pressure applied and controlled by a nitrogen gas cylinder. Atomization gas was supplied by a nitrogen gas cylinder. Additional components in Figure 6A include an atomization nozzle; a deposition chamber; heaters 1 and 2; and a honeycomb sample holder. The apparatus further includes a fan, and sensors and control components including pressure gauges for the atomization gas and liquid pressure, a differential pressure gauge for monitoring cross GPF pressure loss, a flow meter for monitoring total flow rate, and a control valve.

[0073] FIG. 7 illustrates the morphology of an exemplary aggregate or agglomerate 400 according to one or more embodiments. Primary particles 402 are bonded together to form spherical aggregates or agglomerates 400. In one or more embodiments, the primary particles 402 are non-spherical. In some embodiments, the primary particles 402 are oval and non-spherical. In some embodiments, the primary particles 402 comprise non-spherical closed curves. In some embodiments, the primary particles 402 comprise multiple lobes. The surface of each aggregate or agglomerate 400 is rough to provide friction between the aggregate and the pores of the honeycomb. FIGS. 8A-F illustrate the morphology and distribution of material, which may be an inorganic layer, at different depths. The ratio is the distance to the inlet face relative to the total length of the honeycomb body. The honeycomb body can have a first end and a second end. The first end and the second end are separated by an axial length. The aggregates are deposited from the first end to form material, which may be an inorganic layer, on the inlet channel walls of the honeycomb body. In some embodiments, the material, which may be the inorganic layer, extends along the entire axial length of the honeycomb body (i.e., extends along 100% of the axial length). In some embodiments, the layer on the wall of the honeycomb body is not uniform, with thicknesses varying from 10% of the axial length, 50% of the axial length, and 90% of the axial length. The material, which may be the inorganic layer, is thinner at the inlet end (10% of the axial length from the inlet end) and thicker at the outlet end (90% of the axial length from the inlet end). The aggregates or agglomerates 400 block surface pores, effectively reducing pore size.

[0074] The aggregate size distribution and relative pore size distribution from SEM image analysis are listed in Table 1. The average diameters, Q1, Q3, and sample number are listed. The average aggregate size ranged from approximately 1 μm to approximately 3 μm. The average pore size at the end of the channel (90% of the axial length from the inlet end) was smaller than the average pore size at the inlet (10% of the axial length from the inlet end). This is because the material was thicker and more layers of aggregates formed the pores. The average pore size was less than 2.5 μm, significantly smaller than the average pore size of the honeycomb body, which was 14 μm. The pore size was measured from the SEM image as the distance between two adjacent aggregates on the surface. Because the porous inorganic layer is made up of multiple layers of aggregates, the average pore size in three-dimensional measurements should be smaller than the average pore size measured by two-dimensional measurements.

[0075] [Table 1]

[0076] Due to its smaller pore size and thin thickness, Al2O3 provided high filtration efficiency without the cost of a large clean pressure drop. Clean pressure drop is the component pressure drop without soot loading. Soot-loaded pressure drop can be further improved by mitigating soot deep layer penetration.

[0077] Figure 9 compares the filtration efficiency progression with soot loading between an uncoated honeycomb body and a honeycomb body coated with an Al2O3 material, which may be an inorganic layer. At a soot loading of 0.01 g / L, filtration efficiency increased from 78.4% to 97.6%. Simulated laboratory particle number emissions decreased by approximately one order of magnitude, which was also an order of magnitude lower than the Euro 6 regulations for GDI vehicle emissions. The coating effectively accelerated the filtration efficiency to 100% and significantly reduced particle emissions. The filtration efficiency of the honeycomb body herein is measured using the procedure outlined in Tandon et al., 65 CHEMICAL ENGINEERING SCIENCE 4751-60 (2010).

[0078] Figure 10 plots the clean pressure drop against the flow rate. 3 The pressure drop penalty due to the Al2O3 coating at 3 g / L is only 7%. The soot loaded pressure drop in Figure 11 shows the improvement due to the Al2O3 coating, which reduces the pressure drop by 9% at 3 g / L.

[0079] In one or more embodiments, the porosity of the material, which may be an inorganic layer disposed on the wall of the honeycomb body, is from about 20% to about 95%, or from about 25% to about 95%, or from about 30% to about 95%, or from about 40% to about 95%, or from about 45% to about 95%, or from about 50% to about 95%, or from about 55% to about 95%, or from about 60% to about 95%, or from about 65% to about 95%, or from about 70% to about 95%, or from about 75% to about 95%, as measured by mercury intrusion porosimetry, SEM, or X-ray tomography. about 95%, or about 80% to about 95%, or about 85% to about 95%, or about 30% to about 95%, or about 40% to about 95%, or about 45% to about 95%, or about 50% to about 95%, or about 55% to about 95%, or about 60% to about 95%, or about 65% to about 95%, or about 70% to about 95%, or about 75% to about 95%, or about 80% to about 95%, or about 85% to about 95%, or about 20% to about 90%, or about 25% to about 90%, or about 30% to about 90%, or about 4 0% to about 90%, or about 45% to about 90%, or about 50% to about 90%, or about 55% to about 90%, or about 60% to about 90%, or about 65% to about 90%, or about 70% to about 90%, or about 75% to about 90%, or about 80% to about 90%, or about 85% to about 90%, or about 20% to about 85%, or about 25% to about 85%, or about 30% to about 85%, or about 40% to about 85%, or about 45% to about 85%, or about 50% to about 85%, or about 55% to about 85% , or about 60% to about 85%, or about 65% to about 85%, or about 70% to about 85%, or about 75% to about 85%, or about 80% to about 85%, or about 20% to about 80%, or about 25% to about 80%, or about 30% to about 80%, or about 40% to about 80%, or about 45% to about 80%, or about 50% to about 80%, or about 55% to about 80%, or about 60% to about 80%, or about 65% to about 80%, or about 70% to about 80%, or about 75% to about 80%.

[0080] As mentioned above, the material, which may be an inorganic layer, on the walls of the honeycomb body is very thin compared to the thickness of the base portion of the walls of the honeycomb body. As discussed in more detail below, the material, which may be an inorganic layer, on the honeycomb body can be formed by a method that allows the layer to be applied to the surface of the walls of the honeycomb body in a very thin layer. In embodiments, the average thickness of the material, which may be an inorganic layer, on the base portion of the walls of the honeycomb body is from 0.5 μm to 50 μm, or from 0.5 μm to 45 μm, or from 0.5 μm to 40 μm, or from 0.5 μm to 35 μm, or from 0.5 μm to 30 μm, or from 0.5 μm to 25 μm, or from 0.5 μm to 20 μm, or from 0.5 μm to 15 μm, or from 0.5 μm to 10 μm.

[0081] As discussed above, the material, which may be an inorganic layer, can be applied to the walls of the honeycomb body by a method that allows the inorganic material, which may be an inorganic layer, to have a small average pore size. This small average pore size allows the material, which may be an inorganic layer, to filter a high percentage of particulates, preventing them from penetrating the honeycomb and settling within the pores of the honeycomb, as discussed above with reference to FIG. 4. The small average pore size of the material, which may be an inorganic layer according to embodiments, enhances the filtration efficiency of the honeycomb body. In one or more embodiments, the material, which may be an inorganic layer, on the walls of the honeycomb body has an average pore size of 0.1 μm to 5 μm, such as 0.5 μm to 4 μm, or 0.6 μm to 3 μm. For example, in some embodiments, the material, which may be an inorganic layer, on the walls of the honeycomb body may have an average pore size of about 0.5 μm, about 0.6 μm, about 0.7 μm, about 0.8 μm, about 0.9 μm, about 1 μm, about 2 μm, about 3 μm, or about 4 μm.

[0082] In embodiments, the material, which may be an inorganic layer, on the walls of the honeycomb body may cover substantially 100% of the wall surface defining the internal channels of the honeycomb body, while in other embodiments, the material, which may be an inorganic layer, on the walls of the honeycomb body covers substantially less than 100% of the wall surface defining the internal channels of the honeycomb body. For example, in one or more embodiments, the material, which may be an inorganic layer, on the walls of the honeycomb body covers at least 70% of the wall surface defining the internal channels of the honeycomb body, covers at least 75% of the wall surface defining the internal channels of the honeycomb body, covers at least 80% of the wall surface defining the internal channels of the honeycomb body, covers at least 85% of the wall surface defining the internal channels of the honeycomb body, covers at least 90% of the wall surface defining the internal channels of the honeycomb body, or covers at least 85% of the wall surface defining the internal channels of the honeycomb body.

[0083] As described above with reference to Figures 2 and 3, the honeycomb body can have a first end and a second end. The first end and the second end are separated by an axial length. In some embodiments, the layer on the wall of the honeycomb body can extend along the entire axial length of the honeycomb body (i.e., along 100% of the axial length). However, in other embodiments, the material, which may be an inorganic layer, on the wall of the honeycomb body can extend along at least 60% of the axial length, such as extending along at least 65% of the axial length, extending along at least 70% of the axial length, extending along at least 75% of the axial length, extending along at least 80% of the axial length, extending along at least 85% of the axial length, extending along at least 90% of the axial length, or extending along at least 95% of the axial length.

[0084] In embodiments, the material, which may be an inorganic layer, on the walls of the honeycomb body extends from the first end of the honeycomb body to the second end of the honeycomb body, hi some embodiments, the material, which may be an inorganic layer, on the walls of the honeycomb body extends the entire distance from the first surface of the honeycomb body to the second surface of the honeycomb body (i.e., extends along 100% of the distance from the first surface of the honeycomb body to the second surface of the honeycomb body). However, in one or more embodiments, the layer or material on the wall of the honeycomb body, which may be an inorganic layer, extends along 60% of the distance between the first surface of the honeycomb body and the second surface of the honeycomb body, such as extending along 65% of the distance between the first surface of the honeycomb body and the second surface of the honeycomb body, extending along 70% of the distance between the first surface of the honeycomb body and the second surface of the honeycomb body, extending along 75% of the distance between the first surface of the honeycomb body and the second surface of the honeycomb body, extending along 80% of the distance between the first surface of the honeycomb body and the second surface of the honeycomb body, extending along 85% of the distance between the first surface of the honeycomb body and the second surface of the honeycomb body, extending along 90% of the distance between the first surface of the honeycomb body and the second surface of the honeycomb body, or extending along 95% of the distance between the first surface of the honeycomb body and the second surface of the honeycomb body.

[0085] As discussed above, and without being bound by any particular theory, it is believed that low pressure drop is achieved by the honeycomb body of embodiments because the material, which may be an inorganic layer, on the honeycomb body is the primary filtration component of the honeycomb body, allowing for greater flexibility in honeycomb body design. The selection of a honeycomb body having low pressure drop, combined with the thin thickness and low porosity of the layer on the honeycomb body of embodiments, allows the honeycomb body of embodiments to have low pressure drop when compared to conventional honeycomb bodies. In embodiments, the layer is 0.3 to 30 g / L on the honeycomb body, such as 1 to 30 g / L on the honeycomb body, or 3 to 30 g / L on the honeycomb body. In other embodiments, the layer is 1 to 20 g / L on the honeycomb body, such as 1 to 10 g / L on the honeycomb body. In some embodiments, the pressure drop across the honeycomb body (i.e., clean pressure drop without soot or ash) is 20% or less, such as 9% or less, or 8% or less, compared to a honeycomb that does not include the thin porous inorganic material, which may be an inorganic layer. In other embodiments, the pressure drop across the honeycomb body is 7% or less, such as 6% or less. In yet other embodiments, the pressure drop across the honeycomb body is 5% or less, such as 4% or less, or 3% or less.

[0086] As mentioned above, and without being bound by any particular theory, the small pore size in the upper layer of the honeycomb body wall allows the honeycomb body to have good filtration efficiency even before ash or soot accumulation occurs in the honeycomb body. The filtration efficiency of a honeycomb body is measured herein using the procedure outlined in Tandon et al., 65 CHEMICAL ENGINEERING SCIENCE 4751-60 (2010). As used herein, the initial filtration efficiency of a honeycomb body refers to a new or regenerated honeycomb body that does not contain any measurable soot load. In embodiments, the initial filtration efficiency (i.e., clean filtration efficiency) of the honeycomb body is 70% or greater, such as 80% or greater, or 85% or greater. In yet other embodiments, the initial filtration efficiency of the honeycomb body is greater than 90%, such as 93% or greater, or 95% or greater, or 98% or greater.

[0087] The material, which may be an inorganic layer, on the walls of the honeycomb body according to embodiments is thin and has a certain porosity, and in some embodiments, the layer on the walls of the honeycomb body also has good chemical durability and physical stability. The chemical durability and physical stability of the material, which may be an inorganic layer, on the honeycomb body can be determined, in embodiments, by subjecting the honeycomb body to a test cycle including a burn-off cycle and an aging test, and measuring the initial filtration efficiency before and after the test cycle. For example, one exemplary method for measuring the chemical durability and physical stability of a honeycomb body includes measuring the initial filtration efficiency of the honeycomb body, loading soot onto the honeycomb body under simulated operating conditions, burning off the accumulated soot at approximately 650°C, subjecting the honeycomb body to an aging test at 1050°C and 10% humidity for 12 hours, and measuring the filtration efficiency of the honeycomb body. Multiple soot accumulation and burn-off cycles can be performed. A small change in filtration efficiency (ΔF) from pre- to post-test cycle indicates better chemical durability and physical stability of the material, which may be an inorganic layer on the honeycomb body. In some embodiments, ΔF is 5% or less, such as 4% or less, or 3% or less. In other embodiments, ΔF is 2% or less, or 1% or less.

[0088] In some embodiments, the material, which may be an inorganic layer, on the walls of the honeycomb body may be comprised of one or a mixture of ceramic components, such as a ceramic component selected from the group consisting of SiO, AlO, MgO, ZrO, CaO, TiO, CeO, NaO, Pt, Pd, Ag, Cu, Fe, Ni, and mixtures thereof. Thus, the material, which may be an inorganic layer, on the walls of the honeycomb body may include an oxide ceramic. As discussed in more detail below, methods for forming the material, which may be an inorganic layer, on the honeycomb body according to embodiments allow for customization of the layer composition for a given application. This can be beneficial because, for example, ceramic components can be combined to match the physical properties, such as the coefficient of thermal expansion (CTE) and Young's modulus, of the honeycomb body, thereby improving the physical stability of the honeycomb body. In some embodiments, materials that may be inorganic layers on the walls of the honeycomb body may include cordierite, aluminum titanate, enstatite, mullite, forsterite, corundum (SiC), spinel, sapphirine, and periclase.

[0089] In some embodiments, the composition of the material, which may be an inorganic layer, on the walls of the honeycomb body is the same as the composition of the honeycomb body, however, in other embodiments, the composition of the layer is different from the composition of the honeycomb body.

[0090] The properties of the material, which may be an inorganic layer, and therefore the overall honeycomb body, can be attributed to the ability to apply a thin porous material, which may be an inorganic layer, having a small median pore size to the honeycomb body.

[0091] In some embodiments, a method for forming a honeycomb body includes generating or obtaining an aerosol including ceramic precursor materials and a solvent. The ceramic precursor materials of the layer precursor include conventional crude ceramic materials that serve as a source of, for example, SiO, AlO, TiO, MgO, ZrO, CaO, CeO, NaO, Pt, Pd, Ag, Cu, Fe, Ni, etc.

[0092] In one or more embodiments, the well-dispersed aerosol in the fluid is directed to the honeycomb body and deposited on the honeycomb body. In some embodiments, the honeycomb body may have one or more channels plugged at one end, such as at the first end 105 of the honeycomb body, during deposition of the aerosol on the honeycomb body. In some embodiments, the plugged channels may be removed after deposition of the aerosol. However, in other embodiments, the channels may remain plugged after deposition of the aerosol. The pattern of plugged channels in the honeycomb body is not limited, and in some embodiments, all of the channels in the honeycomb body may be plugged at one end. In other embodiments, only a portion of the channels in the honeycomb body may be plugged at one end. In such embodiments, the pattern of plugged and unplugged channels at one end of the honeycomb body is not limited, and may be, for example, a checkerboard pattern in which alternating channels at one end of the honeycomb body are plugged. During deposition of the aerosol, the aerosol can be distributed evenly within the channels 110 of the honeycomb body 100 by plugging all or a portion of the channels at one end of the honeycomb body.

[0093] DETAILED DESCRIPTION OF THE INVENTION Embodiments of the honeycomb bodies and methods for their formation as disclosed and described herein will now be described.

[0094] According to one or more embodiments, a binder that can withstand high temperatures (e.g., greater than 400°C) is included in the material that may be the inorganic layer to improve the integrity of the material that may be the inorganic layer at the high temperatures encountered in automotive exhaust gas emission treatment systems. In a particular embodiment, the material that may be the inorganic layer includes about 5 wt% Dowsil™ US-CF-2405 (alkoxy-siloxane resin). The microstructure of the material that may be the inorganic layer resembled the as-deposited morphology after various tests described below. Inorganic binders Aremco Ceramabind™ 644A and 830 are also used in one or more embodiments of the material that may be the inorganic layer. The filtration efficiency of all samples was measured using a high flow rate blowing test (850 Nm 3 / h) is higher than 60%. This test showed that even when exposed to the high temperatures encountered in engine exhaust gas streams, binders, including organic and inorganic binders, bind primary particles together to form secondary aggregate particles (also called agglomerates), which are bonded to the filter wall. According to one or more embodiments, to increase the mechanical strength of the material, which may be an inorganic layer through a suitable curing process, silicates (e.g., Na2SiO3), phosphates (e.g., AlPO4, AlH2(PO4)3), hydraulic cements (e.g., calcium aluminate), sols (e.g., mSiO2·nH2O, Al(OH) x (H2O) 6-x Other potential inorganic and organic binders, such as SiO 2 and metal alkoxides, may also be utilized in this material, which may be an inorganic layer.

[0095] The present disclosure includes the following number of embodiments: 1. A honeycomb body, 1. A porous ceramic honeycomb structure comprising a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 value, and this d 10 The pore size of 90% of the pores is above the value and the pore size of the remaining 10% of the pores is below the value, d 10 a porous ceramic honeycomb structure including pores having a value; a porous inorganic material disposed on one or more of the wall surfaces, the porous inorganic material comprising primary particles and agglomerates; Including, a. Mean agglomerate size D 50 vs. average wall pore size d of the honeycomb bulk 50 of, in a ratio ranging from 5:1 to 16:1; b. Mean agglomerate size D 50 vs. bulk honeycomb wall pore size d 10 of, in a ratio ranging from 6:1 to 20:1; c. Primary particles that are non-spherical and agglomerates that are spherical; d. 75% of the primary particles have a circularity of less than 0.8 and the agglomerates have a circularity of greater than 0.9; e. a porous material comprising inorganic particles and a binder; and f. a porous material extending from a first end to a second end, the porous material including interrupted, discrete patches of filtering material; A honeycomb body having a property selected from the group consisting of:

[0096] 2. The honeycomb body of embodiment 1, wherein the porous inorganic material comprises a layer having an average thickness greater than about 0.5 μm and less than or equal to 50 μm.

[0097] 3. The honeycomb body of embodiment 1 or 2, wherein the porous inorganic material comprises a layer having an average thickness of 0.5 μm or more and 25 μm or less.

[0098] 4. The honeycomb body of any one of embodiments 1 to 3, wherein the porous inorganic material comprises an oxide ceramic.

[0099] 5. The honeycomb body of any one of embodiments 1 to 4, wherein the porous inorganic material covers at least 70% of the wall surface.

[0100] 6. The honeycomb body of any one of embodiments 1 to 5, wherein the porous inorganic material covers at least 90% of the wall surface.

[0101] 7. The honeycomb body of any one of embodiments 1 to 6, wherein the first end and the second end are spaced apart along the axial length, and the porous inorganic material covers at least 60% along the axial length.

[0102] 8. The honeycomb body of any one of embodiments 1 to 7, wherein the porous honeycomb body has a bulk porosity of 50% or more and 70% or less.

[0103] 9. The honeycomb body of embodiment 1, wherein the porous ceramic honeycomb structure has a bulk average pore size of 10 μm or greater.

[0104] 10. The honeycomb body of any one of embodiments 1 to 9, wherein the porous ceramic honeycomb structure has a bulk average pore size of 15 μm or more.

[0105] 11. The honeycomb body of any one of embodiments 1 to 10, wherein the porous ceramic honeycomb structure has a bulk average pore size of 8 μm or more and 25 μm or less.

[0106] 12. The honeycomb body of any one of embodiments 1 to 11, wherein the porous ceramic honeycomb structure has a surface porosity of 35% or greater.

[0107] 13. The honeycomb body of any one of embodiments 1 to 12, wherein the porous ceramic honeycomb structure has a surface porosity of 40% or greater.

[0108] 14. The honeycomb body of any one of embodiments 1 to 13, wherein the porous ceramic honeycomb structure has a surface porosity of 35% or more and 60% or less.

[0109] 15. The honeycomb body of any one of embodiments 1 to 14, wherein the porous ceramic honeycomb structure has a surface average pore size of 8 μm or more.

[0110] 16. The honeycomb body of any one of embodiments 1 to 15, wherein the porous ceramic honeycomb structure has a surface average pore size of 10 μm or more.

[0111] 17. The honeycomb body of any one of embodiments 1 to 16, wherein the porous ceramic honeycomb structure has a surface average pore size of 8 μm or more and 20 μm or less.

[0112] 18. The honeycomb body of any one of embodiments 1 to 17, wherein the porous inorganic material has a porosity of about 20% to about 95%.

[0113] 19. The honeycomb body of any one of embodiments 1 to 18, wherein the porous inorganic material has a porosity in the range of about 25% to about 95%.

[0114] 20. A method for forming a honeycomb body, comprising: contacting the inorganic material in suspension with a gaseous carrier fluid; depositing an inorganic material onto the ceramic honeycomb body by flowing a gaseous carrier fluid through the ceramic honeycomb body; bonding the inorganic material to the ceramic honeycomb body to produce a porous inorganic material; Including, the porous inorganic material comprises primary particles and agglomerates; 1. A porous ceramic honeycomb structure, wherein the ceramic honeycomb body comprises a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of interior channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 value, and this d 10 The pore size of 90% of the pores is above the value and the pore size of the remaining 10% of the pores is below the value, d 10 and pores having a value, The honeycomb body a. Mean agglomerate size D 50 vs. average wall pore size d of the honeycomb bulk 50 of, in a ratio ranging from 5:1 to 16:1; b. Mean agglomerate size D 50 vs. bulk honeycomb wall pore size d 10 of, in a ratio ranging from 6:1 to 20:1; c. Primary particles that are non-spherical and agglomerates that are spherical; d. 75% of the primary particles have a circularity of less than 0.8 and the agglomerates have a circularity of greater than 0.9; e. a porous material comprising inorganic particles and a binder; and f. a porous material extending from a first end to a second end, the porous material including interrupted, discrete patches of filtering material; The method has a characteristic selected from the group:

[0115] 21. The method of embodiment 20, wherein the porous inorganic material comprises a layer having an average thickness greater than about 0.5 μm and less than or equal to 50 μm.

[0116] 22. The method of embodiment 20 or 21, wherein the porous inorganic material comprises a layer having an average thickness of 0.5 μm or more and 25 μm or less.

[0117] 23. The method of any one of embodiments 20 to 22, wherein the porous inorganic material comprises an oxide ceramic.

[0118] 24. The method of any one of embodiments 20 to 23, wherein the inorganic material comprises a ceramic material.

[0119] 25. The method for forming a honeycomb body of any one of embodiments 20 to 24, wherein the inorganic material is in a suspension that includes a solvent.

[0120] 26. The method for forming a honeycomb body according to embodiment 25, wherein the solvent is selected from the group consisting of methoxyethanol, ethanol, water, xylene, methanol, ethyl acetate, benzene, and mixtures thereof.

[0121] 27. The method for forming a honeycomb body of any one of embodiments 20 to 26, further comprising atomizing the suspension in a nozzle.

[0122] 28. The method for forming a honeycomb body of any one of embodiments 20 to 27, wherein bonding the inorganic material to the ceramic honeycomb body includes including a binder in the suspension. [Example]

[0123] Embodiments will be further understood from the following non-limiting examples.

[0124] Examples 1 to 7 The process flow shown in Figure 5 was followed. A suspension of Al2O3 (30 wt% solids) with an average primary particle size of 150 nm (Beijing Dk Nano Technology Co. Ltd.) was prepared in ethanol and stirred for 1 hour, after which a diluted suspension was prepared to prevent the settling of the Al2O3 primary particles. The raw material components and contents of Examples 1 to 7 are listed in Table 2. For Example 1, the crude suspension was directly diluted to 11 wt% solids in ethanol (AR, Sinopharm Group Co. Ltd.).

[0125] During the atomization step, droplets were generated using a two-phase fluid nozzle (1 / 4J-SS + SU11-SS, Spraying Systems Co.). A schematic diagram of the deposition process is shown in Figure 6A. For Examples 1 to 3, atomization was achieved using a pressure control system. The pressure was supplied by a N2 gas cylinder and adjusted by a pressure regulator. The atomization gas was supplied by a nitrogen supply cylinder at a pressure maintained at 116 psi (approximately 800 kPa), while the mixed suspension was delivered by high-pressure nitrogen from a separate line maintained at a pressure of 78 psi (approximately 540 kPa). For Examples 4 to 7, atomization was achieved using a flow control system using a mass flow controller, and the liquid flow rate was controlled by a syringe pump. The atomization gas was also supplied by a nitrogen cylinder, but was controlled by flow rate instead of pressure. The atomization gas flow rate was fixed at 20 L / min. The mixed suspension was delivered by an injector pump, and the liquid injection rate was fixed at 1.4 ml / min.

[0126] In the drying step, the airflow was heated by heating bands (resistance heaters) in areas H, H1, and H2, marked in red in Figure 6. The temperatures of H1 and H2 were set to 350°C and 200°C, while the temperature of H was set to 350°C. The atomized droplets were dried in the hot airflow to form secondary agglomerate particles before the inlet of the honeycomb filter. The diameter and length of the honeycomb filter used in Examples 1 to 7 were 4.055 inches (about 10.30 cm) and 5.47 inches (about 13.9 cm). The CPSI and wall thickness were 200 (about 31.0 cells / cm).2 ) and 8 mil (about 0.2 mm). In the depositing step, the flow was driven by a fan in the pressure control system and by a pump in the flow control system. The secondary agglomerate particles were transported by the flow and deposited under the wall of the honeycomb filter to form a good material for the inorganic layer. In the curing step, the curing temperatures and times for Examples 2 to 7 are listed in Table 2.

[0127] [Table 2]

[0128] To evaluate the robustness of the inorganic layer, Examples 1 to 7 were subjected to a high flow rate blowing test. The test flow rate was 850 Nm 3 / h, which was much higher than the vehicle exhaust flow rate. The total test time was about 10 minutes, with the highest flow rate lasting for 1 minute. After high-flow blowing, the FE and pressure drop (dP) at a velocity of 1.7 m / s were measured and are listed in Table 3.

[0129] [Table 3]

[0130] The FE values ​​of Examples 2 to 5 were considered stable within the measurement error range. The FE values ​​of Examples 6 and 7 decreased by approximately one-quarter after the high-flow test, but still remained at a 60% level. Comparative Example 1, which did not contain a binder, showed a much greater decrease in FE than the inorganic layer-compatible materials, including the binder examples. These examples demonstrate that the binder improved the strength of the inorganic layer-compatible materials. Example 3 utilized a curing catalyst, shortening the curing time to 4 hours at room temperature. However, the other binder systems required at least 12 hours of curing time, and the curing temperature was 40°C. For Example 3, the FE decrease after the high-flow test was only 3%, the same as Example 2. Therefore, a small amount of an appropriate catalyst can clearly accelerate the curing rate without affecting the strength of the material.

[0131] 8A-F are SEM photographs showing the morphology of the filter wall surface at different depths from the filter inlet. FIG. 8A shows Example 2 at a depth of 10%. FIG. 8B shows Example 2 at a depth of 50%. FIG. 8C shows Example 2 at a depth of 90%. FIG. 8D shows Example 7 at a depth of 10%. FIG. 8E shows Example 7 at a depth of 50%. FIG. 8F shows Example 7 at a depth of 90%.

[0132] Figures 8A-F show the morphology at different depths from the inlet for Examples 2 and 7 after high-flow testing. The material was not a continuous layer, but particles filled the open pores below the surface of the filter. According to one or more embodiments, the material provided herein, which may be an inorganic layer, includes a discontinuous layer formed from the inlet end to the outlet end, including disconnected, discrete patches of material, and a binder consisting of primary particles within secondary aggregate particles or agglomerates that are substantially spherical. In one or more embodiments, the primary particles are non-spherical. In one or more embodiments, "substantially spherical" refers to agglomerates having a cross-sectional circularity factor in the range of about 0.8 to about 1 or about 0.9 to about 1, where 1 represents a perfect circle.

[0133] The material became thicker with increasing depth from the filter inlet. Comparing the microstructures of Examples 2 and 7, the material containing Dowsil™ US-CF-2405 showed better adhesion than the high-temperature inorganic binder 830. Particles present in the surface pores contributed to the FE remaining after high-flow blowing. The material morphology followed the FE measurement results.

[0134] To further verify the mechanical strength of the material containing the binder system, various tests were performed using Example 4. After the high-flow test, the filter was sealed in a can and then placed in a vehicle exhaust pipe (GEELY Emgrand GT, 1.8T GDI). The vehicle was driven on the highway for approximately 1 hour. After the vehicle test, the filter was calcined in a muffle furnace at 650°C for 5 hours to remove soot.

[0135] Vibration tests (76g, 200Hz, 2 hours) were performed by fixing the canned filters in a metal box and then placing them on a vibrating floor. The vibration acceleration was a maximum of 76g, and the frequency was 200Hz. The canned filters were vibrated horizontally for 1 hour and then vertically for another hour. The filters were then treated at 1150°C for 0.5 hours.

[0136] The tests were performed in the following order: high-flow test, canning, first vehicle test, first vibration test, second vibration test, high-temperature treatment, and second vehicle test. FE and dP were measured after each test. FE results remained above 75%, with an overall maximum variation of only 7%. After the first vehicle test, the binder-containing material was subjected to calcination at 650°C for 5 hours, but the filtration efficiency decreased by only 5%. This result indicated that the binder 2405 and the integrity of the material were stable at the high temperatures tested, which are within the normal range of vehicle exhaust temperatures. Filtration efficiency and pressure drop did not change between the two consecutive vibration tests. These results indicated that the binder improved the mechanical integrity of the material in various tests simulating actual use and in the actual vehicle test. With the high-temperature treatment, only a 2% filtration loss was observed. These results demonstrated the thermal robustness of the material. Overall, materials containing appropriate binders were able to achieve the mechanical strength of advanced materials that could withstand a variety of conditions, including high-flow blowing, excessive G-force vibration, high-temperature processing, and actual vehicle engine exhaust processing.

[0137] After various test conditions, the material of Example 4 was examined using a scanning electron microscope. The microstructure of the material after use is shown in Figures 13A-C. As can be seen from Figures 13A-C, the material distribution on the wall is substantially similar to that of Examples 2 and 7. As the depth from the filter inlet increases, the material becomes thicker. All open pores below the surface are filled with particles, which results in high filtration efficiency of the filter. These examples demonstrated that the use of a high-temperature binder was an effective way to build a stable material structure.

[0138] Roundness measurement Samples prepared as in Examples 2-7 were examined using a scanning electron microscope. Primary particles and aggregate particles (agglomerates) were measured for circularity. Figure 14A shows primary particles measured by SEM. The measured primary particles were randomly selected from individual particles. Figure 14B tabulates the measurement data for 25 particles.

[0139] The measured agglomerates are shown in the SEM photograph in Figure 15A. The measured agglomerates were randomly selected. Figure 15B tabulates the measurement data for 25 agglomerates.

[0140] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Accordingly, it is intended that the present specification cover modifications and variations of the various embodiments described herein, provided that such modifications and variations come within the scope of the appended claims and their equivalents.

[0141] Preferred embodiments of the present invention will be described below in detail.

[0142] Embodiment 1 A honeycomb body, 1. A porous ceramic honeycomb structure comprising a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 a porous ceramic honeycomb structure comprising the pores having a value; a porous inorganic material disposed on one or more of the wall surfaces, the porous inorganic material comprising primary particles and agglomerates; Including, Average agglomerate size D 50 vs. d 50the average wall pore size ratio is in the range of 5:1 to 16:1; Honeycomb body.

[0143] Embodiment 2 A honeycomb body, 1. A porous ceramic honeycomb structure comprising a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 a porous ceramic honeycomb structure comprising the pores having a value; a porous inorganic material disposed on one or more of the wall surfaces, the porous inorganic material comprising primary particles and agglomerates; Including, Average agglomerate size D 50 Wall pore size d 10 The ratio is within the range of 6:1 to 20:1, Honeycomb body.

[0144] Embodiment 3 A honeycomb body, 1. A porous ceramic honeycomb structure comprising a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 a porous ceramic honeycomb structure comprising the pores having a value; a porous inorganic material disposed on one or more of the wall surfaces, the porous inorganic material comprising primary particles and agglomerates; Including, the primary particles are non-spherical and the agglomerates are spherical; Honeycomb body.

[0145] Embodiment 4 A honeycomb body, 1. A porous ceramic honeycomb structure comprising a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 a porous ceramic honeycomb structure comprising the pores having a value; a porous inorganic material disposed on one or more of the wall surfaces, the porous inorganic material comprising primary particles and agglomerates; Including, 75% of the primary particles have a circularity of less than 0.8 and agglomerates have a circularity of greater than 0.9. Honeycomb body.

[0146] Embodiment 5 A honeycomb body, 1. A porous ceramic honeycomb structure comprising a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 a porous ceramic honeycomb structure comprising the pores having a value; a porous inorganic material disposed on one or more of the wall surfaces, the porous inorganic material comprising primary particles and agglomerates; Including, The porous material includes inorganic particles and a binder. Honeycomb body.

[0147] Embodiment 6 A honeycomb body, 1. A porous ceramic honeycomb structure comprising a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 a porous ceramic honeycomb structure comprising the pores having a value; a porous inorganic material disposed on one or more of the wall surfaces, the porous inorganic material comprising primary particles and agglomerates; Including, the porous material extends from the inlet end to the outlet end, the porous material comprising interrupted, discrete patches of filtration material; Honeycomb body.

[0148] Embodiment 7 7. The honeycomb body of any one of embodiments 1 to 6, wherein the porous inorganic material comprises a layer having an average thickness greater than about 0.5 μm and less than or equal to 50 μm.

[0149] Embodiment 8 8. The honeycomb body of any one of embodiments 1 to 7, wherein the porous inorganic material comprises a layer having an average thickness of 0.5 μm or more and 25 μm or less.

[0150] Embodiment 9 9. The honeycomb body of any one of claims 1 to 8, wherein the porous inorganic material comprises an oxide ceramic.

[0151] Embodiment 10 10. The honeycomb body of any one of embodiments 1 to 9, wherein the porous inorganic material covers at least 70% of the wall surface.

[0152] Embodiment 11 11. The honeycomb body of any one of embodiments 1 to 10, wherein the porous inorganic material covers at least 90% of the wall surface.

[0153] Embodiment 12 12. The honeycomb body of any one of claims 1 to 11, wherein the first end and the second end are spaced apart by an axial length, and the porous inorganic material covers at least 60% along the axial length.

[0154] Embodiment 13 13. The honeycomb body of any one of embodiments 1 to 12, wherein the porous honeycomb body has a bulk porosity of 50% or more and 70% or less.

[0155] Embodiment 14 14. The honeycomb body of any one of embodiments 1 to 13, wherein the porous ceramic honeycomb structure has a bulk average pore size of 10 μm or more.

[0156] Embodiment 15 15. The honeycomb body of any one of claims 1 to 14, wherein the porous ceramic honeycomb structure has a bulk average pore size of 15 μm or more.

[0157] Embodiment 16 16. The honeycomb body of any one of embodiments 1 to 15, wherein the porous ceramic honeycomb structure has a bulk average pore size of 8 μm or more and 25 μm or less.

[0158] Embodiment 17 17. The honeycomb body of any one of embodiments 1 to 16, wherein the porous ceramic honeycomb structure has a surface porosity of 35% or greater.

[0159] Embodiment 18 18. The honeycomb body of any one of embodiments 1 to 17, wherein the porous ceramic honeycomb structure has a surface porosity of 40% or more.

[0160] Embodiment 19 19. The honeycomb body of any one of embodiments 1 to 18, wherein the porous ceramic honeycomb structure has a surface porosity of 35% or more and 60% or less.

[0161] Embodiment 20 20. The honeycomb body of any one of claims 1 to 19, wherein the porous ceramic honeycomb structure has a surface average pore size of 8 μm or more.

[0162] Embodiment 21 21. The honeycomb body of any one of claims 1 to 20, wherein the porous ceramic honeycomb structure has a surface average pore size of 10 μm or more.

[0163] Embodiment 22 22. The honeycomb body of any one of embodiments 1 to 21, wherein the porous ceramic honeycomb structure has a surface average pore size of 8 μm or more and 20 μm or less.

[0164] Embodiment 23 23. The honeycomb body of any one of embodiments 1 to 22, wherein the porosity of the porous inorganic material is from about 20% to about 95%.

[0165] Embodiment 24 24. The honeycomb body of any one of embodiments 1 to 23, wherein the porosity of the porous inorganic material is in the range of about 25% to about 95%.

[0166] Embodiment 25 1. A method for forming a honeycomb body, comprising: contacting the inorganic material in suspension with a gaseous carrier fluid; depositing the inorganic material on the ceramic honeycomb body by flowing the gaseous carrier fluid through the ceramic honeycomb body; bonding the inorganic material to the ceramic honeycomb body to produce a porous inorganic material; Including, the porous inorganic material comprises primary particles and agglomerates; The ceramic honeycomb body is a porous ceramic honeycomb structure having a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 and said pores having a value, Average agglomerate size D 50 vs. the average wall pore size d of the bulk of the honeycomb body 50 wherein the ratio is in the range of 5:1 to 16:1; method.

[0167] Embodiment 26 1. A method for forming a honeycomb body, comprising: contacting the inorganic material in suspension with a gaseous carrier fluid; depositing the inorganic material on the ceramic honeycomb body by flowing the gaseous carrier fluid through the ceramic honeycomb body; bonding the inorganic material to the ceramic honeycomb body to produce a porous inorganic material; Including, the porous inorganic material comprises primary particles and agglomerates; The ceramic honeycomb body is a porous ceramic honeycomb structure having a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 and said pores having a value, Average agglomerate size D50 vs. the wall pore size d of the bulk honeycomb body 10 wherein the ratio is in the range of 6:1 to 20:1; method.

[0168] Embodiment 27 1. A method for forming a honeycomb body, comprising: contacting the inorganic material in suspension with a gaseous carrier fluid; depositing the inorganic material on the ceramic honeycomb body by flowing the gaseous carrier fluid through the ceramic honeycomb body; bonding the inorganic material to the ceramic honeycomb body to produce a porous inorganic material; Including, the porous inorganic material comprises primary particles and agglomerates; The ceramic honeycomb body is a porous ceramic honeycomb structure having a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 and said pores having a value, the primary particles are non-spherical and the agglomerates are spherical; method.

[0169] Embodiment 28 1. A method for forming a honeycomb body, comprising: contacting the inorganic material in suspension with a gaseous carrier fluid; depositing the inorganic material on the ceramic honeycomb body by flowing the gaseous carrier fluid through the ceramic honeycomb body; bonding the inorganic material to the ceramic honeycomb body to produce a porous inorganic material; Including, the porous inorganic material comprises primary particles and agglomerates; The ceramic honeycomb body is a porous ceramic honeycomb structure having a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 and said pores having a value, 75% of the primary particles have a circularity of less than 0.8 and agglomerates have a circularity of greater than 0.9. method.

[0170] Embodiment 29 1. A method for forming a honeycomb body, comprising: contacting the inorganic material in suspension with a gaseous carrier fluid; depositing the inorganic material on the ceramic honeycomb body by flowing the gaseous carrier fluid through the ceramic honeycomb body; bonding the inorganic material to the ceramic honeycomb body to produce a porous inorganic material; Including, the porous inorganic material comprises primary particles and agglomerates; The ceramic honeycomb body is a porous ceramic honeycomb structure having a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 and said pores having a value, The porous material includes inorganic particles and a binder. method.

[0171] Embodiment 30 1. A method for forming a honeycomb body, comprising: contacting the inorganic material in suspension with a gaseous carrier fluid; depositing the inorganic material on the ceramic honeycomb body by flowing the gaseous carrier fluid through the ceramic honeycomb body; bonding the inorganic material to the ceramic honeycomb body to produce a porous inorganic material; Including, the porous inorganic material comprises primary particles and agglomerates; The ceramic honeycomb body is a porous ceramic honeycomb structure having a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of internal channels, the porous wall surfaces having an average wall pore size d of the bulk of the honeycomb body. 50 wall pores with d 10 The value of d 10 90% of the pores have a pore size above this value and the remaining 10% of the pores have a pore size below this value, 10 and said pores having a value, the porous material extends from the first end to the second end, the porous material comprising interrupted, discrete patches of filtration material; method.

[0172] Embodiment 31 31. The method of any one of embodiments 25 to 30, wherein the porous inorganic material comprises a layer having an average thickness greater than about 0.5 μm and less than or equal to 50 μm.

[0173] Embodiment 32 32. The method of any one of embodiments 25 to 31, wherein the porous inorganic material comprises a layer having an average thickness of 0.5 μm or more and 25 μm or less.

[0174] Embodiment 33 33. The method of any one of embodiments 25 to 32, wherein the porous inorganic material comprises an oxide ceramic.

[0175] Embodiment 34 34. The method of any one of embodiments 25 to 33, wherein the inorganic material comprises a ceramic material.

[0176] Embodiment 35 35. The method for forming a honeycomb body of any one of embodiments 25 to 34, wherein the inorganic material is in a suspension comprising a solvent.

[0177] Embodiment 36 36. The method for forming a honeycomb body of embodiment 35, wherein the solvent is selected from the group consisting of methoxyethanol, ethanol, water, xylene, methanol, ethyl acetate, benzene, and mixtures thereof.

[0178] Embodiment 37 37. The method for forming a honeycomb body of any one of embodiments 25 to 36, further comprising atomizing the suspension in a nozzle.

[0179] Embodiment 38 38. The method for forming a honeycomb body of any one of claims 25 to 37, wherein the step of bonding the inorganic material to the ceramic honeycomb body includes the step of including a binder in the suspension.

Claims

1. 1. A method for forming a ceramic honeycomb body having a porous ceramic honeycomb structure with a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of interior channels, the method comprising: Atomizing a solution containing a binder and inorganic primary particles with an atomizing nozzle to form droplets; drying the droplets to form porous aggregate particles; transporting the porous aggregate particles to the ceramic honeycomb body by a gas stream and depositing the porous aggregate particles on the ceramic honeycomb body to form a porous inorganic material on the porous wall surfaces.

2. The method of claim 1 , wherein the porous inorganic material comprises a layer having an average thickness of greater than 0.5 μm and less than or equal to 50 μm.

3. 3. The method of claim 1, wherein the droplets have an average size in the range of 1 μm to 40 μm.

4. 4. The method of any one of claims 1 to 3, wherein the solution is a suspension, the suspension comprising a solvent selected from the group consisting of methoxyethanol, ethanol, water, xylene, methanol, ethyl acetate, benzene, and mixtures thereof.

5. The method of claim 1 , wherein the drying comprises heating the droplets in a deposition chamber.

6. 6. The method of claim 1, wherein the porous aggregate particles have a circularity greater than 0.

9.

7. 1. A method for forming a ceramic honeycomb body comprising a porous ceramic honeycomb structure having a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of interior channels, the method comprising: Flowing a solution containing an atomizing gas and a suspension of inorganic binder and inorganic primary particles through an atomizing nozzle to form droplets; drying the droplets in a deposition chamber to form porous aggregate particles; transporting the porous aggregate particles to a ceramic honeycomb body by a gas stream, depositing the porous aggregate particles on the ceramic honeycomb body, and causing the inorganic binder to bond the porous aggregate particles to the ceramic honeycomb body; The method wherein the porous aggregate particles have a circularity greater than 0.

9.

8. 8. The method of claim 7, wherein the droplets have an average size in the range of 1 μm to 40 μm.

9. The method of claim 7 or 8, further comprising curing the inorganic binder after said depositing.

10. 1. A method for forming a ceramic honeycomb body comprising a porous ceramic honeycomb structure having a first end, a second end, and a plurality of walls having porous wall surfaces defining a plurality of interior channels, the method comprising: flowing an atomizing gas through an atomizing nozzle; A solution containing a binder and a suspension of inorganic primary particles is flowed into the atomizing nozzle, and the atomizing nozzle atomizes the solution with the atomizing gas to form droplets; drying the droplets by heating them in a deposition chamber, so that the binder binds the inorganic primary particles together to form porous aggregate particles; transporting the porous aggregate particles to a ceramic honeycomb body by a gas stream and depositing the porous aggregate particles on the ceramic honeycomb body to form a porous inorganic material on the ceramic honeycomb body.

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