Method of forming monolithic article

Abstract

A method of forming a monolithic article includes extruding an extrudable composition including a binder, inorganic particles, and graphite particles to form an extrudate, the extrudate including an outer skin and a core disposed within the outer skin; drying the extrudate; degreasing the extrudate in a degreasing atmosphere at one or more degreasing temperatures to remove the binder from the extrudate; and sintering the extrudate in a sintering atmosphere at one or more sintering temperatures to remove the graphite particles from the outer skin of the extrudate and sinter the inorganic particles of the extrudate, thereby forming the unitary article. The one or more degreasing temperatures are less than 650 DEG C. The one or more sintering temperatures are greater than or equal to 650 DEG C, and the oxygen concentration of the sintering atmosphere is less than or equal to 2.5%.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 604,317, filed November 30, 2023, pursuant to 35 USC §119, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This specification generally relates to integral articles, and more specifically to methods for forming integral articles with improved mechanical strength. Background Technology

[0004] One method for removing CO2 from a point source or ambient air involves passing a CO2-containing stream through a bulk material containing an adsorbent that adsorbs the CO2. The CO2 can then be desorbed to remove it (e.g., by heating the bulk material). A convenient way to heat the bulk material is through resistance heating. However, conventional manufacturing processes used to form the bulk article may not be cost-effective and / or have limited scalability.

[0005] Therefore, there has always been a need for cost-effective and scalable methods to form integral products with improved mechanical strength. Summary of the Invention

[0006] According to the first aspect A1, a method of forming an integral article may include: extruding an extrudable composition to form an extrudate, the extrudable composition comprising a binder, inorganic particles, and graphite particles, the extrudate comprising an outer skin and a core disposed within the outer skin; drying the extrudate; degreasing the extrudate in a degreasing atmosphere at one or more degreasing temperatures to remove the binder from the extrudate, wherein the one or more degreasing temperatures are below 650°C; and sintering the extrudate in a sintering atmosphere at one or more sintering temperatures to remove the graphite particles from the outer skin of the extrudate and sinter the inorganic particles of the extrudate, thereby forming the integral article, wherein the one or more sintering temperatures are greater than or equal to 650°C, and the oxygen concentration of the sintering atmosphere is less than or equal to 2.5%.

[0007] The second aspect A2 includes the method described in the first aspect A1, wherein the oxygen concentration of the sintering atmosphere is greater than or equal to 0.0% and less than or equal to 2.5%.

[0008] The third aspect A3 includes the method described in the first aspect A1 or the second aspect A2, wherein the one or more degreasing temperatures are greater than or equal to 200°C and less than 650°C.

[0009] The fourth aspect A4 includes the method of any one of the first to third aspects A1-A3, wherein the degreasing comprises holding the extrudate at a degreasing temperature and in the degreasing atmosphere for more than or equal to 2 hours and less than or equal to 40 hours.

[0010] Fifth aspect A5 includes the method of fourth aspect A4, wherein the degreasing comprises increasing the temperature in the degreasing atmosphere to one of the one or more degreasing temperatures at a first variable rate greater than or equal to 5°C / hour and less than or equal to 20°C / hour.

[0011] The sixth aspect A6 includes the method described in any one of the first to fifth aspects A1-A5, wherein the oxygen concentration of the degreasing atmosphere is greater than or equal to 3% and less than or equal to 18%.

[0012] The seventh aspect A7 includes the method described in any one of the first to sixth aspects A1-A6, wherein the one or more sintering temperatures are greater than or equal to 650°C and less than or equal to 1000°C.

[0013] The eighth aspect A8 includes the method of any one of the first to seventh aspects A1-A7, wherein the sintering comprises holding the extrudate at a holding sintering temperature and in the sintering atmosphere for more than or equal to 0.5 hours and less than or equal to 8 hours.

[0014] The ninth aspect A9 includes the method of the eighth aspect A8, wherein the sintering comprises increasing to the holding sintering temperature at a second sloping rate greater than or equal to 5°C / hour and less than or equal to 100°C / hour.

[0015] The tenth aspect A10 includes the method described in any one of the first to ninth aspects A1-A9, wherein at least one of the degreasing atmosphere and the sintering atmosphere comprises nitrogen, argon, or a combination thereof.

[0016] The eleventh aspect A11 includes the method of any one of the first to tenth aspects A1-A10, wherein the adhesive comprises an organic adhesive, the organic adhesive comprising cellulose, cellulose derivatives, polymers, thermosetting resins or combinations thereof.

[0017] The twelfth aspect A12 includes the method described in any one of the first to eleventh aspects A1-A11, wherein the inorganic particles comprise borates, phosphates, transition metal oxides, oxides, hydroxides, carbonates, silicates, aluminosilicates, or combinations thereof.

[0018] The thirteenth aspect A13 includes the method of the twelfth aspect A12, wherein the inorganic particles comprise talc, clay, MgO, alumina, or a combination thereof.

[0019] The fourteenth aspect A14 includes the method described in any one of the first to thirteenth aspects A1-A13, wherein the graphite particles comprise graphite plates, graphite sheets, natural graphite, synthetic graphite, or combinations thereof.

[0020] The fifteenth aspect A15 includes the method described in any one of the first to fourteenth aspects A1-A14, wherein the extrudable composition further comprises a pore-forming material comprising starch, nut shell powder, carbon, natural polymers, synthetic polymers, carbonaceous materials, crystalline carbon, amorphous carbon, or combinations thereof.

[0021] The sixteenth aspect A16 includes the method described in any one of the first to fifteenth aspects A1-A15, wherein the extrudable composition further comprises a porous material comprising paper, polymer, glass, glass ceramic, ceramic, diatomaceous earth, perlite, pumice, or a combination thereof.

[0022] The seventeenth aspect A17 includes the method of the sixteenth aspect A16, wherein the porous material comprises hollow glass beads.

[0023] The eighteenth aspect A18 includes the method described in any one of the first to seventeenth aspects A1-A17, wherein the core has a honeycomb structure shape, the honeycomb structure comprising a plurality of cells defining parallel channels longitudinally through the honeycomb structure.

[0024] According to aspect 19 A19, an integral article may comprise: an outer skin comprising an inorganic material; and a core disposed within the outer skin, the core comprising a continuous graphite phase and an inorganic phase comprising the inorganic material, wherein the graphite phase and the inorganic phase together form an interconnected porous structure, wherein: the modulus of rupture of the outer skin is at least 150% greater than the modulus of rupture of the core, as measured according to ASTM-D6272; and the integral article is conductive.

[0025] Twentieth aspect A20 includes the integral article described in nineteenth aspect A19, wherein the outer skin is free of or substantially free of graphite.

[0026] The twenty-first aspect A21 includes the integral article described in the nineteenth aspect A19 or the twentieth aspect A20, wherein the continuous graphite phase is uniformly distributed throughout the core.

[0027] The twenty-second aspect A22 includes the integral article of any one of aspects A19 to A21, wherein the core has a honeycomb structure shape, the honeycomb structure comprising a plurality of units defining parallel channels running longitudinally through the honeycomb structure.

[0028] The twenty-third aspect A23 includes the integral article described in any one of the nineteenth to twenty-second aspects A19-A22, wherein the continuous graphite phase comprises calcined graphite plates, graphite sheets, natural graphite, synthetic graphite, or combinations thereof.

[0029] The twenty-fourth aspect A24 includes the integral article of any one of the nineteenth to twenty-third aspects A19-A23, wherein the inorganic material comprises borates, phosphates, transition metal oxides, oxides, hydroxides, carbonates, silicates, aluminosilicates, or combinations thereof.

[0030] The twenty-fifth aspect A25 includes the integral article described in the twenty-fourth aspect A24, wherein the inorganic material comprises talc, clay, MgO, alumina, or a combination thereof.

[0031] Article 26 A26 includes the integral article described in any one of Articles 19 to 25 A19-A25, wherein, as measured according to ASTM C623, the Young's modulus of the outer skin is at least 50% greater than that of the core.

[0032] The twenty-seventh aspect A27 includes the integral article of any one of the nineteenth to twenty-sixth aspects A19-A26, wherein the resistance of the core of the integral article is greater than or equal to 1 ohm and less than or equal to 100 ohms.

[0033] The twenty-eighth aspect A28 includes the integral article of any one of aspects A19-A27, wherein the integral article comprises a coating located on the core, the coating comprising a catalyst, an adsorbent for adsorbing and desorbing CO2, or a combination thereof.

[0034] The twenty-ninth aspect A29 includes a method of using the article of the twenty-eighth aspect A28, the method comprising: exposing the article to a gas stream containing CO2 to adsorb at least a portion of the CO2 in the gas stream into the adsorbent in the coating.

[0035] The thirtieth aspect A30 includes the method of the twenty-ninth aspect A29, the method further comprising: desorbing CO2 from the coating.

[0036] The thirty-first aspect A31 includes the method of the thirty-tenth aspect A30, wherein the desorption comprises applying an electric potential across the article to heat the article.

[0037] According to aspect 32 A32, a method of forming a porous conductive article may include: heating a precursor in a first heating atmosphere within a first atmosphere temperature range, the precursor comprising a precursor composition comprising inorganic particles, one or more organic components, and a conductive filler material, wherein the first atmosphere temperature range is below the combustion temperature of the conductive filler material, wherein the precursor comprises a core surrounded by a periphery having the same precursor composition, wherein the precursor is heated in the first heating atmosphere at one or more first atmosphere temperatures within the first atmosphere temperature range, and wherein the heating in the first heating atmosphere is performed for a first heating duration and at the one or more first atmosphere temperatures, the first heating duration and the one or more first atmosphere temperatures... The temperature is sufficient to remove the organic components from the precursor while the conductive filler material remains intact in the precursor; and the precursor is heated in a second heating atmosphere within a second atmosphere temperature range, the second atmosphere temperature range including one or more second atmosphere temperatures equal to or higher than the combustion temperature of the conductive filler material, wherein the second heating atmosphere has a gas composition that inhibits the combustion of the conductive filler material, wherein the heating in the second heating atmosphere is carried out for a second heating duration and at the one or more second atmosphere temperatures, the second heating duration and the one or more second atmosphere temperatures being sufficient to remove at least a portion of the conductive filler material from the periphery of the precursor while the conductive filler material remains intact in the core of the precursor.

[0038] The thirty-third aspect A33 includes the method of the thirty-second aspect A32, wherein heating the precursor in the second heating atmosphere is sufficient to sinter the inorganic material in the outer periphery of the precursor.

[0039] The thirty-fourth aspect A34 includes the method described in the thirty-second aspect A32 or the thirty-third aspect A33, wherein the strength of the periphery is greater than the strength of the core.

[0040] The thirty-fifth aspect A35 includes the method described in aspects A32-A34, wherein heating the precursor in the first heating atmosphere increases the porosity of the precursor.

[0041] The thirty-sixth aspect A36 includes the method described in any one of the thirty-two to thirty-five aspects A32-A35, wherein the average thickness of the outer periphery is less than 10% of the transverse hydraulic diameter of the precursor.

[0042] The thirty-seventh aspect A37 includes the method described in any one of the thirty-two to thirty-sixth aspects A32-A36, wherein the precursor comprises a honeycomb structure, the honeycomb structure comprising intersecting walls extending in an axial direction, the intersecting walls forming a plurality of parallel units in a transverse plane.

[0043] The thirty-eighth aspect A38 includes the method described in any one of the thirty-second to thirty-seventh aspects A32-A37, wherein the gas composition in the second heated atmosphere that prevents the combustion of the conductive filler material is provided by: adjusting the oxygen input and / or level in the second atmosphere; adjusting the fuel mixture of one or more burners that provide heat to the second atmosphere; adjusting the introduction and / or level of recirculated combustion gas products in the second atmosphere; adjusting the introduction and / or level of inert gas in the second atmosphere; or a combination thereof.

[0044] The thirty-ninth aspect A39 includes the method of the thirty-eighth aspect A38, wherein the fuel mixture of the one or more burners is a lean fuel mixture.

[0045] Fortieth aspect A40 includes the method described in thirty-eighth aspect A38 or thirty-ninth aspect A39, wherein the inert gas is nitrogen, argon, or a combination thereof.

[0046] The forty-first aspect A41 includes the method of any one of the thirty-second to fortieth aspects A32-A40, further comprising: extruding the extrudable composition to form an extrudate; and cutting a portion of the extrudate.

[0047] A42 includes the method of A41 in aspect 41, wherein the core and the periphery of the precursor are extruded simultaneously.

[0048] A43 includes the method described in any one of A32-A42 of A32 to A42, wherein the temperature range of the first atmosphere is greater than or equal to 200°C and less than or equal to 650°C.

[0049] A44 includes the method described in any one of A32-A43 of the 32nd to 43rd aspects, wherein the oxygen content of the second atmosphere is in the range of a second oxygen content greater than or equal to 0.0% and less than or equal to 2.5%.

[0050] The forty-fifth aspect A45 includes the method described in any one of the thirty-second to forty-fourth aspects A32-A44, wherein the oxygen content of the first atmosphere is within a first oxygen range of greater than or equal to 3% and less than or equal to 18%.

[0051] A46 includes the method described in any one of A32-A45 of A32 to A45, wherein the first heating duration is greater than or equal to 2 hours and less than or equal to 10 hours.

[0052] Aspect 47 includes the method described in any one of aspects A32-A46, wherein the second heating duration is greater than or equal to 0.5 hours and less than or equal to 8 hours.

[0053] The forty-eighth aspect A48 includes the method described in any one of the thirty-second to forty-seventh aspects A32-A47, wherein the precursor further comprises hollow glass beads.

[0054] The forty-ninth aspect A49 includes the method of the forty-eighth aspect A48, wherein the hollow glass beads are softened when the precursor is heated in the second heating atmosphere.

[0055] The fiftieth aspect A50 includes the method described in the forty-eighth aspect A48 or the forty-ninth aspect A49, wherein the hollow glass beads are hollow glass microspheres.

[0056] Fifty-one aspect A51 includes the method described in any one of aspects A32-A50, wherein the precursor further comprises one or more porous materials, the porous materials comprising paper, polymer, glass, glass ceramic, ceramic, diatomaceous earth, perlite, pumice, or combinations thereof.

[0057] The 52nd aspect A52 includes the method described in any one of the 32nd to 51st aspects A32-A51, wherein the organic component comprises one or more starches, one or more binders, one or more oils, one or more volatile organic compounds, or combinations thereof.

[0058] The 53rd aspect A53 includes the method of the 52nd aspect A52, wherein the one or more adhesives are cellulose adhesives.

[0059] The 54th aspect A54 includes the method described in any one of the 32nd to 53rd aspects A32-A53, wherein the precursor is integral, and wherein the core and the periphery are made of the same composition.

[0060] Further features and advantages of the integral article and its formation method described herein will be set forth in the detailed description below, and these features and advantages will become apparent in part from the description or be recognized by those skilled in the art through practice of the embodiments described herein (including the detailed description below, the claims, and the drawings).

[0061] 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 features of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated in and form a part of this specification. The drawings illustrate the various embodiments described herein and, together with the description, serve to explain the principles and operation of the claimed subject matter. Attached Figure Description

[0062] Figure 1 This is a flowchart of a method for forming an integral article according to one or more embodiments described herein;

[0063] Figure 2 This is a schematic diagram of an extrusion for forming an integral article according to one or more embodiments described herein;

[0064] Figure 3 This is a plot of shrinkage (left y-axis; in dL / Lo) and expansion (right y-axis) of an integral article subjected to different atmospheric conditions according to one or more embodiments described herein as a function of temperature (x-axis; in °C).

[0065] Figure 4 This is a plot of the shrinkage (left y-axis; in dL / Lo) and expansion (right y-axis) of an integral article under different atmospheric conditions as a function of temperature (x-axis; in °C) according to one or more embodiments described herein;

[0066] Figure 5 This is a plot of the relative mass change (left y-axis; in percentage (%)) and heat flux (right y-axis; in watts per gram (W / g)) of an overall article subjected to different atmospheric conditions according to one or more embodiments described herein as a function of temperature (x-axis; in °C).

[0067] Figure 6 This is a plot of temperature (left y-axis; in °C) and weight loss (left y-axis; in percentage (%)) as well as dilatational shrinkage (right y-axis; in mm) and oxygen content (right y-axis; in percentage (%)) of an integral article subjected to different atmospheric conditions according to one or more embodiments described herein, as a function of time (x-axis; in hours).

[0068] Figure 7 It is a plot of the temperature (left y-axis; in °C) and dilatational contraction (right y-axis (in mm)) of an integral article subjected to different atmospheric conditions according to one or more embodiments described herein as a function of time (x-axis; in hours);

[0069] Figure 8This is a plot of temperature (left y-axis; in °C) and oxygen content (right y-axis; in percentage (%)) of an overall article subjected to a given atmospheric condition according to one or more embodiments described herein as a function of time (x-axis; in hours);

[0070] Figure 9 This is a plot of temperature (left y-axis; in °C) and oxygen content (right y-axis; in percentage (%)) of an overall article subjected to a given atmospheric condition according to one or more embodiments described herein as a function of time (x-axis; in hours);

[0071] Figure 10 These are photographs of exemplary overall articles of manufacture according to one or more embodiments described herein;

[0072] Figure 11 These are photographs of the outer skin of an exemplary integral article of one or more embodiments described herein;

[0073] Figure 12 yes Figure 11 A scanning electron microscope (SEM) image of the outer skin of an exemplary integral article;

[0074] Figure 13 yes Figure 11 A further magnified SEM image of the outer skin of an exemplary integral article;

[0075] Figure 14 yes Figure 11 A photograph of the core of an exemplary overall article.

[0076] Figure 15 yes Figure 11 SEM image of the core of an exemplary overall product; and

[0077] Figure 16 yes Figure 11 A further magnified SEM image of the core of an exemplary integral article. Detailed Implementation

[0078] Referring now to various embodiments of a method for forming an integral article with improved mechanical strength. According to an embodiment, a method for forming a transparent ceramic article includes: extruding an extrudable composition to form an extrudate, the extrudable composition comprising a binder, inorganic particles, and graphite particles, the extrudate comprising an outer skin and a core disposed within the outer skin; drying the extrudate; degreasing the extrudate in a degreasing atmosphere at one or more degreasing temperatures to remove the binder from the extrudate; and sintering the extrudate in a sintering atmosphere at one or more sintering temperatures to remove the graphite particles from the outer skin of the extrudate and sinter the inorganic particles of the extrudate, thereby forming the integral article. As used herein, the term integral is intended to mean a structure having one or more continuous phases; however, as disclosed herein, multiple independent continuous phases do not necessarily need to be bonded together, but can be physically held or locked together by intertwining. The one or more degreasing temperatures are below 650°C. The one or more sintering temperatures are greater than or equal to 650°C, and the oxygen concentration of the sintering atmosphere is less than or equal to 2.5%.

[0079] According to other embodiments, the integral article includes an outer skin comprising inorganic material and a core disposed within the outer skin. The core comprises a continuous graphite phase and an inorganic phase comprising inorganic material. The graphite phase and the inorganic phase together form an interconnected porous structure. The modulus of rupture of the outer skin is at least 150% greater than that of the core, as measured according to ASTM-D6272. The integral article is conductive.

[0080] This document will specifically refer to the accompanying drawings to describe various embodiments of the integral article and the method of forming thereof.

[0081] In this document, a range may be expressed as from “about” a specific value and / or to “about” another specific value. Another embodiment of expressing such a range includes from one specific value and / or to another specific value. Similarly, when a value is expressed as an approximation using the antecedent “about,” it should be understood that a specific value forms another embodiment. It should be further understood that the endpoints of each range are significant relative to and independent of the other endpoint.

[0082] As used herein, directional terms (e.g., up, down, right, left, front, back, top, bottom) refer only to the descriptions in the accompanying drawings and are not intended to imply absolute orientation.

[0083] Unless otherwise expressly stated, it is never intended to interpret any method set forth herein as requiring its steps to be performed in a particular order, nor is it intended to require any particular orientation of any device. Therefore, it is never intended to infer any order or orientation in any respect where a method claim does not actually describe the order in which its steps are followed, or where any device claim does not actually describe the order or orientation of individual components, or where the claims or description do not otherwise specifically specify that the steps are limited to a particular order, or where a particular order or orientation of the components of the device is not described. This applies to any possible non-expressive basis for interpretation, including: logical questions relating to the arrangement of steps, the flow of operations, the order of components, or the orientation of components; simple meanings derived from grammatical organization or punctuation; and the number or type of embodiments described in the description.

[0084] As used herein, unless the context explicitly indicates otherwise, the singular forms “a / an” and “the” include plural indicators. Thus, for example, unless the context explicitly indicates otherwise, a reference to “a” component includes aspects having two or more such components.

[0085] “Oxygen” and “O2” are used interchangeably in this article.

[0086] “Nitrogen” and “N2” are used interchangeably in this article.

[0087] As used in this article, “d” 50 "Diameter" refers to the average particle size by mass, which makes the d of a certain material... 50 The diameter is smaller than 50% of the material by mass and also larger than 50% of the material by mass.

[0088] As used in this article, “modulus of fracture” or “MOR” is measured according to ASTM-D6272 by performing a four-point bending test on a rectangular bar cut from a fired part.

[0089] As used in this article, "Young's modulus" is provided in gigapascals (GPa) and is measured according to ASTM C623.

[0090] As used in this article, “resistance” was measured with a multimeter on a 2-inch × 6-inch (5 cm × 15 cm) sample.

[0091] As used in this article, “porosity” or “total pore volume” is measured using mercury porosity according to ASTM D6761-07 (2012).

[0092] As used in this article, “weight loss” is measured by measuring the sample before and after processing.

[0093] As used in this article, "standard volume exchange" refers to the number of times the atmosphere in the kiln turns over per hour.

[0094] Monolithic articles, especially those containing graphite, can be used for CO2 capture applications, such as direct air capture (DAC) or capturing CO2 at effluent sources. During use, a CO2-containing stream flows through a monolith containing an adsorbent that adsorbs CO2. After use, the CO2 can be desorbed and removed by heating the monolith (e.g., resistance heating).

[0095] Conventional processes for forming integral articles can be carried out in a low-oxygen or anaerobic atmosphere (e.g., in an atmosphere containing nitrogen and / or argon) to prevent graphite oxidation and retain graphite throughout the article. For example, the article can be fired in a closed ceramic dome crucible, where a green biscuit-like structure on top of the article acts as a sacrificial oxidant to provide low oxygen, thereby retaining as much graphite as possible in the article during firing. However, such conventional processes may not be cost-effective due to the use of nitrogen or argon, or their scalability may be limited due to the need to maintain a low-oxygen or anaerobic atmosphere.

[0096] This document discloses a method for forming an integral article that mitigates the aforementioned problems. Specifically, the method for forming an integral article disclosed herein controls the temperature and / or atmosphere during debinding and sintering, thereby producing a conductive integral article with improved mechanical strength. Specifically, the method for forming an integral article disclosed herein includes debinding at a relatively low temperature (e.g., below 650°C), which retains graphite in the extrudate. The method disclosed herein also includes sintering the extrudate at a relatively high temperature (e.g., greater than or equal to 650°C) and in a relatively low oxygen atmosphere (e.g., oxygen concentration less than or equal to 2.5%), which removes graphite from the outer skin of the extrudate while retaining graphite in the core of the extrudate. The graphite in the core allows the resulting integral article to be conductive. Therefore, the resulting integral article is also referred to herein as a "porous conductive article". Removing graphite from the outer skin enables enhanced bonding and sintering of the inorganic particles in the outer skin, thereby enhancing the outer skin and the overall article (e.g., the modulus of rupture of the outer skin is at least 150% greater than that of the core).

[0097] Now for reference Figure 1 A method for forming an integral article is shown at 100. The method begins at box 102 by extruding an extrudable composition to form an extrudate (also referred to herein as a “precursor”). The extrudable composition (also referred to herein as a “precursor composition”) comprises a binder, inorganic particles, and graphite particles.

[0098] A binder (also referred to herein as "one or more organic components") provides mechanical adhesion to the extrudable composition during extrusion and drying. In embodiments, the binder may comprise an organic binder. In embodiments, the organic binder may comprise cellulose, cellulose derivatives, polymers, thermosetting resins, or combinations thereof. In embodiments, the cellulose derivative may comprise (C1-C3)alkylhydroxy(C1-C3)alkylcellulose, (C1-C3)alkylhydroxycellulose, (C1-C3)alkylcellulose, (C1-C3)alkyl(C1-C3)alkylcellulose, methylhydroxypropylcellulose, methylhydroxyethylcellulose, methylhydroxymethylcellulose, methylcellulose, ethylcellulose, propylcellulose, hydroxypropylcellulose, methylethylcellulose, sodium carboxymethylcellulose, or combinations thereof. In embodiments, the binder may comprise a cellulose binder.

[0099] In embodiments, the amount of binder in the extrudable composition, relative to 100 parts of inorganic particles, can be greater than or equal to 1 part, greater than or equal to 3 parts, or even greater than or equal to 5 parts. In embodiments, the amount of binder in the extrudable composition, relative to 100 parts of inorganic particles, can be less than or equal to 15 parts, less than or equal to 10 parts, or even less than or equal to 7 parts. In embodiments, the amount of binder in the extrudable composition, relative to 100 parts of inorganic particles, can be greater than or equal to 1 part and less than or equal to 15 parts, greater than or equal to 1 part and less than or equal to 10 parts, greater than or equal to 1 part and less than or equal to 7 parts, greater than or equal to 3 parts and less than or equal to 15 parts, greater than or equal to 3 parts and less than or equal to 10 parts, greater than or equal to 3 parts and less than or equal to 7 parts, or any and all subranges formed by any of these endpoints.

[0100] During sintering, inorganic particles provide mechanical strength to the resulting monolithic article. Some inorganic particles (such as silicates) can also enhance the extrudability of extrudable compositions. In embodiments, inorganic particles may comprise borates, phosphates, transition metal oxides, oxides, hydroxides, carbonates, silicates, aluminosilicates, or combinations thereof. For example, in embodiments, inorganic particles may comprise talc, clay, MgO, alumina, or combinations thereof.

[0101] A minimum amount (e.g., greater than or equal to 20 wt%) of inorganic particles may be included in the extrudable composition to ensure that the resulting monolithic article has sufficient mechanical strength (e.g., the modulus of rupture of the outer skin is at least 150% greater than that of the core). The amount of inorganic particles may be limited (e.g., less than or equal to 85%) to ensure that a continuous graphite phase can be achieved in the resulting monolithic article. In embodiments, based on the total dry weight of the extrudable composition, the amount of inorganic particles in the extrudable composition may be greater than or equal to 20 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, or even greater than or equal to 50 wt%. In embodiments, based on the total dry weight of the extrudable composition, the amount of inorganic particles in the extrudable composition may be less than or equal to 85 wt%, less than or equal to 75 wt%, less than or equal to 65 wt%, less than or equal to 55 wt%, or even less than or equal to 45 wt%. In the embodiments, based on the total dry weight of the extrudable composition, the amount of inorganic particles in the extrudable composition can be greater than or equal to 20 wt% and less than or equal to 85 wt%, greater than or equal to 20 wt% and less than or equal to 75 wt%, greater than or equal to 20 wt% and less than or equal to 65 wt%, greater than or equal to 20 wt% and less than or equal to 55 wt%, greater than or equal to 20 wt% and less than or equal to 45 wt%, greater than or equal to 30 wt% and less than or equal to 85 wt%, greater than or equal to 30 wt% and less than or equal to 75 wt%, greater than or equal to 30 wt% and less than or equal to 65 wt%, greater than or equal to 30 wt% and less than or equal to 55 wt%, greater than or equal to 30 wt% and less than or equal to 45 wt%, greater than or equal to 40 wt% and less than or equal to 85 wt%, greater than or equal to 40 wt% and less than or equal to 75 wt%, greater than or equal to 40 wt% and less than or equal to 65 wt%. wt%, greater than or equal to 40 wt% and less than or equal to 55 wt%, greater than or equal to 40 wt% and less than or equal to 45 wt%, greater than or equal to 50 wt% and less than or equal to 85 wt%, greater than or equal to 50 wt% and less than or equal to 75 wt%, greater than or equal to 50 wt% and less than or equal to 65 wt%, or even greater than or equal to 50 wt% and less than or equal to 55 wt%, or any and all subranges formed by any of these endpoints.

[0102] The extrudable composition includes graphite particles (also referred to herein as "conductive filler") such that the resulting overall article is conductive. In embodiments, the graphite particles may comprise graphite plates, graphite sheets, natural graphite, synthetic graphite, or combinations thereof.

[0103] In embodiments, the graphite particles may comprise elongated shapes and / or planar shapes with a height less than their length and width. In embodiments, the median longest dimension (e.g., diameter) of the graphite particles can be greater than or equal to 1 micrometer and less than or equal to 100 micrometers, greater than or equal to 1 micrometer and less than or equal to 75 micrometers, greater than or equal to 1 micrometer and less than or equal to 50 micrometers, greater than or equal to 1 micrometer and less than or equal to 25 micrometers, greater than or equal to 1 micrometer and less than or equal to 10 micrometers, greater than or equal to 10 micrometers and less than or equal to 100 micrometers, greater than or equal to 10 micrometers and less than or equal to 75 micrometers, greater than or equal to 10 micrometers and less than or equal to 50 micrometers, greater than or equal to 10 micrometers and less than or equal to 25 micrometers, greater than or equal to 25 micrometers and less than or equal to 100 micrometers, greater than or equal to 25 micrometers and less than or equal to 75 micrometers, greater than or equal to 25 micrometers and less than or equal to 50 micrometers, greater than or equal to 50 micrometers and less than or equal to 100 micrometers, greater than or equal to 50 micrometers and less than or equal to 75 micrometers, or even greater than or equal to 75 micrometers and less than or equal to 100 micrometers, or any and all subranges formed by any of these endpoints. In embodiments, the aspect ratio (e.g., the ratio of thickness to diameter) of the graphite particles can be 1:2 to 1:100, 1:2 to 1:75, 1:2 to 1:50, 1:2 to 1:25, 1:2 to 1:10, 1:10 to 1:100, 1:10 to 1:75, 1:10 to 1:50, 1:10 to 1:25, 1:25 to 1:100, 1:25 to 1:75, 1:25 to 1:50, 1:50 to 1:100, 1:50 to 1:75, or even 1:75 to 1:100, or any and all subranges formed by any of these endpoints.

[0104] A minimum amount (e.g., greater than or equal to 5 wt%) of graphite particles can be included in the extrudable composition to ensure a continuous graphite phase, thereby producing a conductive monolithic article. The amount of graphite particles can be limited (e.g., less than or equal to 40 wt%) to ensure adequate bonding and sintering of the inorganic particles, thereby improving mechanical strength (e.g., the modulus of rupture of the outer skin is at least 150% greater than that of the core). In embodiments, the amount of graphite particles in the extrudable composition can be greater than or equal to 5 wt%, greater than or equal to 10 wt%, or even greater than or equal to 15 wt%, based on the total dry weight of the extrudable composition. In embodiments, the amount of graphite particles in the extrudable composition can be less than or equal to 40 wt%, less than or equal to 35 wt%, less than or equal to 30 wt%, or even less than or equal to 25 wt%, based on the total dry weight of the extrudable composition. In embodiments, based on the total dry weight of the extrudable composition, the amount of graphite particles in the extrudable composition may be greater than or equal to 5 wt% and less than or equal to 40 wt%, greater than or equal to 5 wt% and less than or equal to 35 wt%, greater than or equal to 5 wt% and less than or equal to 30 wt%, greater than or equal to 5 wt% and less than or equal to 25 wt%, greater than or equal to 10 wt% and less than or equal to 40 wt%, greater than or equal to 10 wt% and less than or equal to 35 wt%, greater than or equal to 10 wt% and less than or equal to 30 wt%, greater than or equal to 10 wt% and less than or equal to 25 wt%, greater than or equal to 15 wt% and less than or equal to 40 wt%, greater than or equal to 15 wt% and less than or equal to 35 wt%, greater than or equal to 15 wt% and less than or equal to 30 wt%, or even greater than or equal to 15 wt% and less than or equal to 25 wt%, or any and all subranges formed by any of these endpoints.

[0105] In embodiments, the extrudable composition may further comprise a pore-forming material. During degreasing, the pore-forming material may degrade and / or pyrolyze (e.g., burn off) to form pores in the integral article. In embodiments, the pore-forming material may comprise starch (e.g., cross-linked starch, such as cross-linked pea starch), nut shell powder, carbon, natural polymers, synthetic polymers, carbonaceous materials, crystalline carbon, amorphous carbon, or combinations thereof.

[0106] In embodiments, the amount of pore-forming material in the extrudable composition may be greater than or equal to 5 parts, greater than or equal to 10 parts, or even greater than or equal to 15 parts relative to 100 parts of inorganic particles. In embodiments, the amount of pore-forming material in the extrudable composition may be less than or equal to 45 parts, less than or equal to 35 parts, or even less than or equal to 25 parts relative to 100 parts of inorganic particles. In embodiments, the amount of pore-forming material in the extrudable composition, relative to 100 parts of inorganic particles, may be greater than or equal to 5 parts and less than or equal to 45 parts, greater than or equal to 5 parts and less than or equal to 35 parts, greater than or equal to 5 parts and less than or equal to 25 parts, greater than or equal to 10 parts and less than or equal to 45 parts, greater than or equal to 10 parts and less than or equal to 35 parts, greater than or equal to 10 parts and less than or equal to 25 parts, greater than or equal to 15 parts and less than or equal to 35 parts, or even greater than or equal to 15 parts and less than or equal to 25 parts, or any and all subranges formed by any of these endpoints.

[0107] In embodiments, the extrudable composition may further comprise a porous material. In embodiments, the porous material may comprise paper, polymer, glass, glass-ceramic, ceramic, diatomaceous earth, perlite, pumice, or combinations thereof. In embodiments, the porous material may comprise hollow glass beads. In embodiments, the hollow glass beads have a d... 50 The diameter can be greater than or equal to 10 micrometers and less than or equal to 100 micrometers, greater than or equal to 10 micrometers and less than or equal to 75 micrometers, greater than or equal to 10 micrometers and less than or equal to 50 micrometers, greater than or equal to 10 micrometers and less than or equal to 25 micrometers, greater than or equal to 25 micrometers and less than or equal to 100 micrometers, greater than or equal to 25 micrometers and less than or equal to 75 micrometers, greater than or equal to 25 micrometers and less than or equal to 50 micrometers, greater than or equal to 50 micrometers and less than or equal to 100 micrometers, greater than or equal to 50 micrometers and less than or equal to 75 micrometers, or even greater than or equal to 75 micrometers and less than or equal to 100 micrometers, or any and all sub-ranges formed by any of these endpoints. In embodiments, hollow glass beads may comprise hollow glass microspheres.

[0108] In embodiments, based on the total dry weight of the extrudable composition, the amount of porous material may be greater than or equal to 25 wt%, greater than or equal to 30 wt%, or even greater than or equal to 35 wt%. In embodiments, based on the total dry weight of the extrudable composition, the amount of porous material may be less than or equal to 55 wt%, or even less than or equal to 25 wt%. In embodiments, based on the total dry weight of the extrudable composition, the amount of porous material may be greater than or equal to 25 wt% and less than or equal to 55 wt%, greater than or equal to 25 wt% and less than or equal to 45 wt%, greater than or equal to 30 wt% and less than or equal to 55 wt%, greater than or equal to 30 wt% and less than or equal to 45 wt%, greater than or equal to 35 wt% and less than or equal to 55 wt%, or even greater than or equal to 35 wt% and less than or equal to 45 wt%, or any and all subranges formed by any of these endpoints.

[0109] In embodiments, the extrudable composition may include other additives (such as boric acid, potassium carbonate, or combinations thereof) to enhance extrudability or provide strength during processing or in the final product. In embodiments, the extrudable composition may include other additives, such as lubricants, like mineral oils.

[0110] In embodiments, the extrudable composition may further comprise one or more solvents, such as aqueous solvents or organic solvents. In embodiments, the solvent may comprise water, mineral oil, or a combination thereof. In embodiments, the amount of solvent in the extrudable composition, relative to 100 parts of inorganic particles, may be greater than or equal to 25 parts, greater than or equal to 35 parts, or even greater than or equal to 45 parts. In embodiments, the amount of solvent in the extrudable composition, relative to 100 parts of inorganic particles, may be less than or equal to 75 parts, less than or equal to 65 parts, or even less than or equal to 55 parts. In the embodiments, the amount of solvent in the extrudable composition, relative to 100 parts of inorganic particles, can be greater than or equal to 25 parts and less than or equal to 75 parts, greater than or equal to 25 parts and less than or equal to 65 parts, greater than or equal to 25 parts and less than or equal to 55 parts, greater than or equal to 35 parts and less than or equal to 75 parts, greater than or equal to 35 parts and less than or equal to 65 parts, greater than or equal to 35 parts and less than or equal to 55 parts, greater than or equal to 45 parts and less than or equal to 75 parts, greater than or equal to 45 parts and less than or equal to 65 parts, or even greater than or equal to 45 parts and less than or equal to 55 parts, or any and all subranges formed by any of these endpoints.

[0111] Now for reference Figure 2Extruder 150 comprises an outer skin 152 (also referred to herein as a “periphery” or “peripheral region”) and a core 154 disposed within and surrounded by the outer skin 152. In embodiments, the outer skin 152 and the core 154 may have the same extrudable composition. In embodiments, method 100 may comprise cutting a portion of extruder 150 and then degreasing and sintering said portion. In embodiments, the outer skin 152 and the core 154 may be extruded simultaneously.

[0112] In an embodiment, the average thickness of the outer skin 152 may be less than 10%, less than 8%, less than 6%, less than 4%, or even less than 2% of the transverse hydraulic diameter of the extrudate 150.

[0113] The extrudate 150 can have any shape such that the resulting integral article is sufficient to fulfill its intended purpose. For example, in an embodiment, the core 154 can have a honeycomb structure 156 containing a plurality of cells 158. The plurality of cells 158 can define parallel channels 160 extending longitudinally through the honeycomb structure 156. Intersecting walls 162 can extend in the axial direction to form cells 158 in the transverse plane.

[0114] The honeycomb structure 156 can have any suitable circumferential profile or shape, such as a circle, ellipse, square, rectangle, hexagon, triangle, polygon, or irregular shape. When viewed from one end of the honeycomb structure 156, the cell 158 can have any suitable profile, such as a circle, ellipse, square, rectangle, hexagon, triangle, polygon, or irregular shape (such as a honeycomb shape). For example, as Figure 2As shown, one possible combination is a cylindrical article (circular circumferential profile) with square cells. Compared to other forms (such as packed granular beds), the use of the honeycomb structure 156 can advantageously reduce the pressure drop of the fluid flow from one axial end of the honeycomb structure 156 to the other. The honeycomb structure 156 can include any suitable number of cells 158 / square inch (e.g., as measured when viewed from one end). For example, in an embodiment, the cellular structure 156 may have greater than or equal to 20 and less than or equal to 1000 cells / square inch, greater than or equal to 20 and less than or equal to 750 cells / square inch, greater than or equal to 20 and less than or equal to 500 cells / square inch, greater than or equal to 20 and less than or equal to 250 cells / square inch, greater than or equal to 20 and less than or equal to 100 cells / square inch, greater than or equal to 20 and less than or equal to 50 cells / square inch, greater than or equal to 50 and less than or equal to 1000 cells / square inch, greater than or equal to 50 and less than or equal to 750 cells / square inch, greater than or equal to 50 and less than or equal to 500 cells / square inch, greater than or equal to 50 and less than or equal to 250 cells / square inch, and greater than or equal to 50 and less than or equal to 100 cells / square inch. Cellular structures 156 may have any and all subranges formed by any of these endpoints. Cells 158 in cellular structure 156 may have any suitable wall thickness. The cell 158 in cellular structure 156 may have any suitable wall thickness.For example, in an embodiment, the wall thickness of the cells 158 in the cellular structure 156 can be greater than or equal to 0.001 inches and less than or equal to 0.1 inches, greater than or equal to 0.001 inches and less than or equal to 0.05 inches, greater than or equal to 0.001 inches and less than or equal to 0.01 inches, greater than or equal to 0.005 inches and less than or equal to 0.1 inches, greater than or equal to 0.005 inches and less than or equal to 0.05 inches, greater than or equal to 0.005 inches and less than or equal to 0.01 inches, greater than or equal to 0.01 inches and less than or equal to 0.1 inches, or even greater than or equal to 0.01 inches and less than or equal to 0.05 inches, or any and all subranges formed by any of these endpoints. In an embodiment, the cells 158 in the cellular structure 156 can include a 100 / 8 geometry or 2008 cells / square inch / 0.001 inch wall thickness. In an embodiment, the diameter of the cellular structure 156 may be greater than or equal to 3 inches and less than or equal to 15 inches, greater than or equal to 3 inches and less than or equal to 12 inches, greater than or equal to 3 inches and less than or equal to 9 inches, greater than or equal to 3 inches and less than or equal to 6 inches, greater than or equal to 6 inches and less than or equal to 15 inches, greater than or equal to 6 inches and less than or equal to 12 inches, greater than or equal to 6 inches and less than or equal to 9 inches, greater than or equal to 9 inches and less than or equal to 15 inches, greater than or equal to 9 inches and less than or equal to 12 inches, or even greater than or equal to 12 inches and less than or equal to 15 inches, or any and all subranges formed by any of these endpoints. In an embodiment, the length of the cellular structure 156 may be greater than or equal to 3 inches and less than or equal to 15 inches, greater than or equal to 3 inches and less than or equal to 12 inches, greater than or equal to 3 inches and less than or equal to 9 inches, greater than or equal to 3 inches and less than or equal to 6 inches, greater than or equal to 6 inches and less than or equal to 15 inches, greater than or equal to 6 inches and less than or equal to 12 inches, greater than or equal to 6 inches and less than or equal to 9 inches, greater than or equal to 9 inches and less than or equal to 15 inches, greater than or equal to 9 inches and less than or equal to 12 inches, or even greater than or equal to 12 inches and less than or equal to 15 inches, or any and all subranges formed by any of these endpoints.

[0115] Return to reference Figure 1 The method continues at frame 104 with the following operation: drying the extrudate 150 ( Figure 2Drying can be any suitable drying process that substantially removes the solvent from the extrudate 150. In embodiments, drying can include heating, airflow, exposure to microwaves or other energy sources, or combinations thereof. In embodiments, drying can include placing the extrudate 150 under a vacuum. In embodiments, drying can include drying at a sufficient temperature (e.g., greater than or equal to 80°C and less than or equal to 130°C) and for a sufficient duration to substantially remove all solvent from the extruded composition (e.g., such that, based on the total weight of the dried extrudate, the solvent content of the dried extrudate is less than 5 wt%, or less than 2 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0.1 wt%). The drying temperature and time can depend on the size of the extrudate and / or the solvent content.

[0116] Return to reference Figure 1 The method continues at frame 106 with the following operation: extruding material 150 ( Figure 2 Degreasing is performed in a degreasing atmosphere at one or more degreasing temperatures to remove the binder from the extrudate 150. The “degreasing atmosphere” is also referred to herein as the “first heating atmosphere.” The “one or more degreasing temperatures” are also referred to herein as “one or more first atmosphere temperatures” within a “first atmosphere temperature range.” Incomplete burning of the binder results in the presence of coke (e.g., carbonaceous material) in the resulting monolithic article. Therefore, degreasing removes the binder from the extrudate 150 to prevent carbonization. Degreasing also removes pore-forming materials present in the extrudate 150, thereby creating pores in the extrudate 150 and increasing its porosity.

[0117] The one or more degreasing temperatures may be below 650°C to limit or prevent graphite oxidation. In an embodiment, the first atmosphere temperature range may be below the combustion temperature of the conductive filler material. In an embodiment, the one or more degreasing temperatures may be greater than or equal to 200°C to ensure sufficient removal of the binder and pore-forming material (if present). Therefore, in an embodiment, the one or more degreasing temperatures may be greater than or equal to 200°C and less than 650°C. In an embodiment, the one or more degreasing temperatures may be greater than or equal to 200°C, greater than or equal to 250°C, greater than or equal to 300°C, greater than or equal to 350°C, or even greater than or equal to 400°C. In an embodiment, the degreasing temperature may be less than 650°C, less than or equal to 600°C, less than or equal to 550°C, less than or equal to 500°C, less than or equal to 450°C, or even less than or equal to 400°C. In the embodiments, the degreasing temperature can be greater than or equal to 200°C and less than 650°C, greater than or equal to 200°C and less than or equal to 600°C, greater than or equal to 200°C and less than or equal to 550°C, greater than or equal to 200°C and less than or equal to 500°C, greater than or equal to 200°C and less than or equal to 450°C, greater than or equal to 200°C and less than or equal to 400°C, greater than or equal to 250°C and less than or equal to 650°C, greater than or equal to 250°C and less than or equal to 600°C, greater than or equal to 250°C and less than or equal to 500°C, greater than or equal to 250°C and less than or equal to 450°C, greater than or equal to 250°C and less than or equal to 400°C, greater than or equal to 300°C and less than 650°C, greater than or equal to 300°C and less than or equal to 600°C, greater than or equal to 300°C and less than or equal to 550°C. 300°C or higher and 500°C or higher, 300°C or higher and 450°C or higher, 300°C or higher and 400°C or higher, 350°C or higher and 650°C or higher, 350°C or higher and 600°C or higher, 350°C or higher and 550°C or higher, 350°C or higher and 500°C or higher, 350°C or higher and 450°C or higher, 350°C or higher and 400°C or higher, 400°C or higher and 650°C or higher, 400°C or higher and 600°C or higher, 400°C or higher and 550°C or higher, 400°C or higher and 500°C or higher, or even 400°C or higher and 450°C or higher, or any and all subranges formed by any of these endpoints.

[0118] The extrudate can be 150 ( Figure 2The extrudate 150 is held at a holding degreasing temperature (i.e., one of the one or more degreasing temperatures) for a sufficient amount of time (i.e., a first heating duration) to remove the binder from the extrudate 150 while the graphite particles remain intact. This time duration can depend on the extrudable composition, the shape of the extrudate 150, and / or the size of the extrudate 150. Since degreasing of the extrudate 150 only needs to last for a sufficient amount of time to remove the binder, the rate of change of the degreasing temperature can also affect the degreasing holding time, and vice versa. For example, if the rate of change of the degreasing temperature is relatively slow (e.g., 5°C / hour), the time the extrudate is held at the holding degreasing temperature can be relatively short (e.g., 2 hours). In embodiments, degreasing may comprise holding the extrudate 150 at the holding degreasing temperature for greater than or equal to 2 hours to less than or equal to 40 hours. In embodiments, degreasing may comprise holding the extrudate 150 at the holding degreasing temperature for greater than or equal to 2 hours, greater than or equal to 4 hours, greater than or equal to 6 hours, greater than or equal to 8 hours, or even greater than or equal to 10 hours. In embodiments, degreasing may include holding the extrudate 150 at a degreasing temperature for less than or equal to 40 hours, less than or equal to 30 hours, less than or equal to 20 hours, or even less than or equal to 10 hours. In embodiments, degreasing may include holding the extrudate 150 at a degreasing temperature for more than or equal to 2 hours to less than or equal to 40 hours, more than or equal to 2 hours to less than or equal to 30 hours, more than or equal to 2 hours to less than or equal to 20 hours, more than or equal to 2 hours to less than or equal to 10 hours, more than or equal to 4 hours to less than or equal to 40 hours, more than or equal to 4 hours to less than or equal to 30 hours, more than or equal to 4 hours to less than or equal to 20 hours, more than or equal to 4 hours to less than or equal to 10 hours, more than or equal to 6 hours to less than or equal to 40 hours, more than or equal to 6 hours to less than or equal to 40 hours, or more than or equal to 6 hours to less than or equal to 40 hours. Any and all subranges formed by any of these endpoints, ranging from 30 hours or more, 6 hours or more to 20 hours or more, 6 hours or more to 10 hours or more, 8 hours or more to 40 hours or more, 8 hours or more to 30 hours or more, 8 hours or more to 20 hours or more, 8 hours or more to 10 hours or more, 10 hours or more to 40 hours or more, 10 hours or more to 30 hours or more, or even 10 hours or more to 20 hours or more, or any and all subranges formed by any of these endpoints.

[0119] Regarding the rate of change for maintaining the degreasing temperature, as mentioned in this article, due to the extrudate at 150 ( Figure 2The degreasing process only needs to last for a sufficient amount of time to remove the binder; therefore, the degreasing holding time can affect the rate of change of the degreasing temperature reached, and vice versa. Additionally, considering the size of the extrudate 150, it may be necessary to control the rate of change of the degreasing temperature reached. For example, for a relatively large extrudate 150, the temperature / heat may be concentrated at the core 154 of the extrudate 150 (…). Figure 2 Accumulation within. Therefore, the rate of change of the degreasing temperature can be controlled to maintain the degreasing temperature, so that the core 154 and the outer skin 152 ( Figure 2 The temperature difference between the two is below a threshold at which cracking may occur. In an embodiment, degreasing may involve increasing the temperature to a holding degreasing temperature at a first inclination rate greater than or equal to 5°C / hour and less than or equal to 20°C / hour. In an embodiment, the first inclination rate may be greater than or equal to 5°C / hour, or even greater than or equal to 10°C / hour. In an embodiment, the first inclination rate may be less than or equal to 20°C / hour, or even less than or equal to 15°C / hour. In an embodiment, the first inclination rate may be greater than or equal to 5°C / hour and less than or equal to 20°C / hour, greater than or equal to 5°C / hour and less than or equal to 15°C / hour, greater than or equal to 10°C / hour and less than or equal to 20°C / hour, or even greater than or equal to 10°C / hour and less than or equal to 15°C / hour, or any and all subranges formed by any of these endpoints.

[0120] In embodiments, the degreasing and sintering steps described herein can be performed in a furnace (e.g., a kiln). Therefore, the degreasing temperature and sintering temperature described herein refer to furnace temperatures. The atmosphere in the furnace (e.g., a kiln) can be controlled by a combination of an O2 setpoint and optimizing the burner λ to operate in a slightly lean fuel mixture and / or by controlling the recirculation of combustion gas products or additional excess nitrogen. In embodiments, the gas composition of the first heating atmosphere and / or the second heating atmosphere can be provided by: adjusting the oxygen input and / or level in the atmosphere; adjusting the fuel mixture of one or more burners providing heat to the atmosphere; adjusting the introduction and / or level of recirculated combustion gas products in the atmosphere; adjusting the introduction and / or level of inert gases in the atmosphere; or a combination thereof. In embodiments, the one or more burners are lean fuel mixtures. In embodiments, at least one of the degreasing atmosphere and the sintering atmosphere described herein may contain nitrogen, argon, or a combination thereof as inert gases.

[0121] The degreasing atmosphere may have a minimum oxygen concentration (e.g., greater than or equal to 3%) to ensure sufficient oxygen is available for removing binders and pore-forming materials (if present). The amount of oxygen concentration may be limited (e.g., less than or equal to 18%) to prevent graphite oxidation during degreasing. Therefore, in embodiments, the oxygen concentration of the degreasing atmosphere (also referred to as the "first oxygen range") may be greater than or equal to 3% and less than or equal to 18%. In embodiments, the oxygen concentration of the degreasing atmosphere may be greater than or equal to 3%, greater than or equal to 5%, or even greater than or equal to 7%. In embodiments, the oxygen concentration of the degreasing atmosphere may be less than or equal to 18%, less than or equal to 15%, less than or equal to 12%, or even less than or equal to 9%. In embodiments, the oxygen concentration of the degreasing atmosphere may be greater than or equal to 3% and less than or equal to 18%, greater than or equal to 3% and less than or equal to 15%, greater than or equal to 3% and less than or equal to 12%, greater than or equal to 3% and less than or equal to 9%, greater than or equal to 5% and less than or equal to 18%, greater than or equal to 5% and less than or equal to 15%, greater than or equal to 5% and less than or equal to 12%, greater than or equal to 5% and less than or equal to 9%, greater than or equal to 7% and less than or equal to 18%, greater than or equal to 7% and less than or equal to 15%, greater than or equal to 7% and less than or equal to 12%, or even greater than or equal to 7% and less than or equal to 9%, or any and all subranges formed by any of these endpoints.

[0122] Return to reference Figure 1 Method 100 continues the following operation at box 108: extrudate 150 ( Figure 2 ) is sintered in a sintering atmosphere at one or more sintering temperatures to extract from the outer skin 152 of the extrudate 150. Figure 2 The inorganic particles of the extrudate 150 are removed and sintered in a sintering process to form a monolithic article. The “sintering atmosphere” is also referred to herein as a “second heating atmosphere.” The “one or more sintering temperatures” are also referred to herein as “one or more second atmosphere temperatures” within a “second atmosphere temperature range.” Sintering is carried out at a relatively high temperature (e.g., greater than or equal to 650°C) and in a relatively low oxygen atmosphere (e.g., oxygen concentration less than or equal to 2.5%), which oxidizes and removes graphite from the skin of the extrudate while retaining graphite in the core of the extrudate. In embodiments, the second heating atmosphere has a gas composition that inhibits the combustion of conductive filler materials. Graphite in the core allows the resulting monolithic article to be conductive. Removing graphite from the skin enables enhanced bonding and sintering of the inorganic particles in the skin, thereby strengthening the skin and the overall article (e.g., the skin’s modulus of rupture is at least 150% greater than the core’s modulus of rupture).

[0123] As described herein, the one or more sintering temperatures can be greater than or equal to 650°C to ensure the sintering of graphite oxidation and inorganic particles. In embodiments, the second atmosphere temperature range can be equal to or higher than the combustion temperature of the conductive filler. The one or more sintering temperatures can be limited (e.g., less than or equal to 1000°C) to prevent the core 154 of the extrudate 150 ( Figure 2 The graphite within the sintering process. Therefore, in embodiments, the one or more sintering temperatures can be greater than or equal to 650°C and less than or equal to 1000°C. In embodiments, the one or more sintering temperatures can be greater than or equal to 650°C and less than or equal to 1000°C. In embodiments, the one or more sintering temperatures can be greater than or equal to 650°C, greater than or equal to 700°C, greater than or equal to 750°C, or even greater than or equal to 800°C. In embodiments, the one or more sintering temperatures can be less than or equal to 1000°C, less than or equal to 950°C, less than or equal to 900°C, or even less than or equal to 950°C. In embodiments, the one or more sintering temperatures can be greater than or equal to 650°C and less than or equal to 1000°C, greater than or equal to 650°C and less than or equal to 950°C, greater than or equal to 650°C and less than or equal to 900°C, greater than or equal to 650°C and less than or equal to 850°C, greater than or equal to 700°C and less than or equal to 1000°C, greater than or equal to 700°C and less than or equal to 950°C, greater than or equal to 700°C and less than or equal to 900°C, greater than or equal to 700°C and less than or equal to 850°C, greater than or equal to... 750°C and less than or equal to 1000°C, greater than or equal to 750°C and less than or equal to 950°C, greater than or equal to 750°C and less than or equal to 900°C, greater than or equal to 750°C and less than or equal to 850°C, greater than or equal to 800°C and less than or equal to 1000°C, greater than or equal to 800°C and less than or equal to 950°C, greater than or equal to 800°C and less than or equal to 900°C, or even greater than or equal to 800°C and less than or equal to 850°C, or any and all subranges formed by any of these endpoints.

[0124] As described herein, the oxygen concentration in the sintering atmosphere can be limited (e.g., less than or equal to 2.5%) to preserve the core 154 of the extrudate 150. Figure 2The graphite in the sintering atmosphere. Therefore, in embodiments, the oxygen concentration of the sintering atmosphere can be less than or equal to 2.5%. In embodiments, the oxygen concentration of the sintering atmosphere can be greater than or equal to 0.0% and less than or equal to 2.5%. In embodiments, the oxygen concentration of the sintering atmosphere (also referred to herein as the "second oxygen range") can be greater than or equal to 0.0%, or even greater than or equal to 0.5%. In embodiments, the oxygen concentration of the sintering atmosphere can be less than or equal to 2.5%, less than or equal to 2.0%, less than or equal to 1.5%, or even less than or equal to 1.0%. In embodiments, the oxygen concentration of the sintering atmosphere may be greater than or equal to 0.0% and less than or equal to 2.5%, greater than or equal to 0.0% and less than or equal to 2.0%, greater than or equal to 0.0% and less than or equal to 1.5%, greater than or equal to 0.0% and less than or equal to 1.0%, greater than or equal to 0.5% and less than or equal to 2.5%, greater than or equal to 0.5% and less than or equal to 2.0%, greater than or equal to 0.5% and less than or equal to 1.5%, or even greater than or equal to 0.5% and less than or equal to 1.0%, or any and all subranges formed by any of these endpoints.

[0125] The extrudate can be 150 ( Figure 2 The sintering temperature is maintained at a certain time (i.e., a second heating duration) (e.g., greater than or equal to 0.5 hours) for a period of time sufficient to allow heat to escape from the outer skin 152. Figure 2 Graphite is removed and inorganic particles are sintered in the process. The extrudate 150 can be held at the sintering temperature for a limited time (e.g., less than or equal to 8 hours) to ensure the core 154 of the extrudate 150 (…). Figure 2No graphite oxidation occurs in the process, and the graphite particles remain intact in the core. Therefore, in embodiments, sintering may involve holding the extrudate 150 at a holding sintering temperature for ≥0.5 hours to ≤8 hours. In embodiments, sintering may involve holding the extrudate 150 at a holding sintering temperature for ≥0.5 hours, ≥1 hour, ≥2 hours, or even ≥4 hours. In embodiments, sintering may involve holding the extrudate 150 at a holding sintering temperature for ≤8 hours, ≤6 hours, or even ≤4 hours. In an embodiment, sintering may include holding the extrudate 150 at a holding sintering temperature for ≥0.5 hours to ≤8 hours, ≥0.5 hours to ≤6 hours, ≥0.5 hours to ≤4 hours, ≥1 hour to ≤8 hours, ≥1 hour to ≤6 hours, ≥1 hour to ≤4 hours, ≥2 hours to ≤8 hours, ≥2 hours to ≤6 hours, ≥2 hours to ≤4 hours, ≥4 hours to ≤8 hours, or even ≥4 hours to ≤6 hours, or any and all subranges formed by any of these endpoints.

[0126] In one embodiment, sintering may involve increasing the temperature to a holding sintering temperature at a second ramp rate greater than or equal to 5°C / hour and less than or equal to 100°C / hour. In another embodiment, the second ramp rate may be greater than or equal to 5°C / hour, greater than or equal to 10°C / hour, greater than or equal to 20°C / hour, greater than or equal to 30°C / hour, greater than or equal to 40°C / hour, or even greater than or equal to 50°C / hour. In yet another embodiment, the second ramp rate may be less than or equal to 100°C / hour, less than or equal to 80°C / hour, less than or equal to 60°C / hour, less than or equal to 40°C / hour, or even less than or equal to 20°C / hour. In embodiments, the second ramp rate can be greater than or equal to 5°C / hour and less than or equal to 100°C / hour, greater than or equal to 5°C / hour and less than or equal to 80°C / hour, greater than or equal to 5°C / hour and less than or equal to 60°C / hour, greater than or equal to 5°C / hour and less than or equal to 40°C / hour, greater than or equal to 5°C / hour and less than or equal to 20°C / hour, greater than or equal to 10°C / hour and less than or equal to 100°C / hour, greater than or equal to 10°C / hour and less than or equal to 80°C / hour, greater than or equal to 10°C / hour and less than or equal to 60°C / hour, greater than or equal to 10°C / hour and less than or equal to 40°C / hour, greater than or equal to 10°C / hour and less than or equal to 20°C / hour, greater than or equal to 20°C / hour and less than or equal to 100°C / hour, greater than or equal to 20°C / hour and less than or equal to 80°C / hour, greater than or equal to 20°C / hour and less than or equal to 80°C / hour, or greater than or equal to 20°C / hour. The following are all subranges that are less than or equal to 60°C / hour, greater than or equal to 20°C / hour and less than or equal to 40°C / hour, greater than or equal to 30°C / hour and less than or equal to 100°C / hour, greater than or equal to 30°C / hour and less than or equal to 80°C / hour, greater than or equal to 30°C / hour and less than or equal to 60°C / hour, greater than or equal to 30°C / hour and less than or equal to 40°C / hour, greater than or equal to 40°C / hour and less than or equal to 100°C / hour, greater than or equal to 40°C / hour and less than or equal to 80°C / hour, or even greater than or equal to 50°C / hour and less than or equal to 60°C / hour, or any and all subranges formed by any of these endpoints. During debinding, binder removal and temperature difference can be considered when determining the rate of change to reach the holding debinding temperature. These debinding reactions have already occurred during sintering, which allows the rate of change to reach the holding sintering temperature to be relatively faster than the rate of change to reach the holding debinding temperature.

[0127] In one embodiment, degreasing and sintering can be performed in a single step, such that the furnace temperature is gradually changed from the degreasing temperature to the sintering temperature. In other embodiments, degreasing and sintering can be performed in two steps, such that the temperature is gradually reduced from the degreasing temperature (e.g., to ambient temperature) and then gradually changed to the sintering temperature.

[0128] The integral article obtained by the method disclosed herein comprises an outer skin and a core disposed within the outer skin, said outer skin and core being related to... Figure 2 The outer skin and core of the extruded material 150 shown are similar or identical.

[0129] The outer skin of the integral article may comprise inorganic materials. Inorganic materials can be formed by bonding and sintering inorganic particles of the extrudable composition. Therefore, in the embodiments, the inorganic material may comprise materials similar to or the same as those described above regarding the inorganic particles of the extrudable composition. Because the sintering temperature used in the methods described herein is relatively low (e.g., less than or equal to 1000°C), the inorganic particles are softened during sintering and may not form a single phase (e.g., cordierite).

[0130] The method disclosed herein is used to extract the outer skin 152 of the extrudate 150 ( Figure 2 Graphite is removed from the outer skin of the integral article so that the outer skin of the integral article is free of or substantially free of graphite. For example, in an embodiment, the amount of graphite in the outer skin of the integral article may be less than or equal to 10%, less than or equal to 5%, less than or equal to 3%, or even less than or equal to 1% of the amount of graphite in the outer skin of the extrusion forming the integral article.

[0131] The core of the integral article may comprise a continuous graphite phase and an inorganic phase comprising inorganic materials. The graphite and inorganic phases together form an interconnected porous structure. In embodiments, the continuous graphite phase may be uniformly distributed throughout the core. The method disclosed herein preserves the core 154 of the extrudate 150 (…). Figure 2 The graphite in the core of the integral article. Therefore, in embodiments, the continuous graphite phase of the core of the integral article may comprise calcined graphite plates, graphite sheets, natural graphite, synthetic graphite, or combinations thereof. The graphite plates, graphite sheets, natural graphite, and / or synthetic graphite calcined to form the continuous graphite phase may be the same as or similar to the graphite plates, graphite sheets, natural graphite, and / or synthetic graphite described above with respect to the graphite particles of the extrudable composition. In embodiments, the core 154 of the integral article may comprise an inorganic matrix in which the conductive material is dispersed throughout the inorganic matrix.

[0132] In embodiments, porous materials, when present in the extrudable composition, may be present in the monolithic article. For example, while materials such as paper and polymers may be burned off by degreasing and / or sintering processes, glass, glass ceramics, ceramics, diatomaceous earth, perlite, and / or pumice may be retained in the monolithic article. In embodiments, hollow glass beads present in the extrudate may be softened in a second heating atmosphere. In embodiments, the monolithic article may contain, for example, hollow glass beads that have burst and / or broken due to sintering. In embodiments, the monolithic article may contain no or substantially no unburst and / or broken hollow glass beads. For example, in embodiments, based on the total weight of the monolithic article, the amount of unburst and unbreakable hollow glass beads may be less than or equal to 5 wt%, less than or equal to 4 wt%, less than or equal to 3 wt%, less than or equal to 2 wt%, less than or equal to 1 wt%, less than or equal to 0.5 wt%, less than or equal to 0.1 wt%, or even equal to 0 wt%.

[0133] Because graphite is removed from the outer skin, the overall mechanical strength of the article can be improved. In an embodiment, the strength of the outer skin can be greater than the strength of the core. In an embodiment, the modulus of rupture of the outer skin can be at least 150% greater than the modulus of rupture of the core. In an embodiment, the modulus of rupture of the outer skin can be at least 150%, at least 160%, at least 170%, at least 180%, at least 190%, or at least 200% greater than the modulus of rupture of the core.

[0134] In the embodiments, the modulus of rupture of the outer skin of the integral article can be greater than or equal to 0.5 MPa, greater than or equal to 0.6 MPa, greater than or equal to 0.7 MPa, or even greater than or equal to 0.8 MPa. In the embodiments, the modulus of rupture of the outer skin of the integral article can be less than or equal to 1.2 MPa, less than or equal to 1.1 MPa, or even less than or equal to 1.0 MPa. In embodiments, the modulus of rupture of the outer skin of the integral article may be greater than or equal to 0.5 MPa and less than or equal to 1.2 MPa, greater than or equal to 0.5 MPa and less than or equal to 1.1 MPa, greater than or equal to 0.5 MPa and less than or equal to 1.0 MPa, greater than or equal to 0.6 MPa and less than or equal to 1.2 MPa, greater than or equal to 0.6 MPa and less than or equal to 1.1 MPa, greater than or equal to 0.6 MPa and less than or equal to 1.0 MPa, greater than or equal to 0.7 MPa and less than or equal to 1.2 MPa, greater than or equal to 0.7 MPa and less than or equal to 1.1 MPa, greater than or equal to 0.7 MPa and less than or equal to 1.0 MPa, greater than or equal to 0.8 MPa and less than or equal to 1.2 MPa, greater than or equal to 0.8 MPa and less than or equal to 1.1 MPa, or even greater than or equal to 0.8 MPa and less than or equal to 1.0 MPa, or any and all subranges formed by any of these endpoints.

[0135] In one embodiment, the core of the integral article may have a fracture modulus greater than or equal to 0.1 MPa, greater than or equal to 0.2 MPa, or even greater than or equal to 0.3 MPa. In another embodiment, the core of the integral article may have a fracture modulus less than or equal to 0.6 MPa, less than or equal to 0.5 MPa, or even less than or equal to 0.4 MPa. In an embodiment, the core of the integral article may have a fracture modulus greater than or equal to 0.1 MPa and less than or equal to 0.6 MPa, greater than or equal to 0.1 MPa and less than or equal to 0.5 MPa, greater than or equal to 0.1 MPa and less than or equal to 0.4 MPa, greater than or equal to 0.2 MPa and less than or equal to 0.6 MPa, greater than or equal to 0.2 MPa and less than or equal to 0.5 MPa, greater than or equal to 0.2 MPa and less than or equal to 0.4 MPa, greater than or equal to 0.3 MPa and less than or equal to 0.6 MPa, greater than or equal to 0.3 MPa and less than or equal to 0.5 MPa, or even greater than or equal to 0.3 MPa and less than or equal to 0.4 MPa, or any and all subranges formed by any of these endpoints.

[0136] In an embodiment, the outer skin of the integral article may be harder than the core. In an embodiment, the Young's modulus of the outer skin may be at least 50% greater than that of the core. In an embodiment, the Young's modulus of the outer skin may be at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, or even 75% greater than that of the core.

[0137] In an embodiment, the Young's modulus of the outer skin of the integral article may be greater than or equal to 0.4 GPa, or even greater than or equal to 0.5 GPa. In an embodiment, the Young's modulus of the outer skin of the integral article may be less than or equal to 0.7 GPa, or even less than or equal to 0.6 GPa. In an embodiment, the Young's modulus of the outer skin of the integral article may be greater than or equal to 0.4 GPa and less than or equal to 0.7 GPa, greater than or equal to 0.4 GPa and less than or equal to 0.6 GPa, greater than or equal to 0.5 GPa and less than or equal to 0.7 GPa, or even greater than or equal to 0.5 GPa and less than or equal to 0.6 GPa, or any and all subranges formed by any of these endpoints.

[0138] In one embodiment, the Young's modulus of the core of the integral article can be greater than or equal to 0.2 GPa, or even greater than or equal to 0.3 GPa. In another embodiment, the Young's modulus of the core of the integral article can be less than or equal to 0.4 GPa. In yet another embodiment, the Young's modulus of the core of the integral article can be greater than or equal to 0.2 GPa and less than or equal to 0.4 GPa, or even greater than or equal to 0.3 GPa and less than or equal to 0.4 GPa, or any and all subranges formed by any of these endpoints.

[0139] Because graphite is retained in the core, the entire article is conductive. Therefore, the entire article can be considered a porous conductive article. In embodiments, the resistance of the core of the entire article can be greater than or equal to 1 ohm to less than or equal to 100 ohms. In embodiments, the resistance of the core of the entire article can be greater than or equal to 1 ohm, greater than or equal to 5 ohms, greater than or equal to 10 ohms, greater than or equal to 25 ohms, or even greater than or equal to 50 ohms. In embodiments, the resistance of the core of the entire article can be less than or equal to 100 ohms, less than or equal to 75 ohms, less than or equal to 50 ohms, or even less than or equal to 25 ohms. In the embodiments, the resistance of the core of the overall article can be greater than or equal to 1 ohm and less than or equal to 100 ohms, greater than or equal to 1 ohm and less than or equal to 75 ohms, greater than or equal to 1 ohm and less than or equal to 50 ohms, greater than or equal to 1 ohm and less than or equal to 25 ohms, greater than or equal to 5 ohms and less than or equal to 100 ohms, greater than or equal to 5 ohms and less than or equal to 75 ohms, greater than or equal to 5 ohms and less than or equal to 50 ohms, greater than or equal to 5 ohms and less than or equal to 25 ohms, or greater than or equal to 10 ohms and less than or equal to 100 ohms. 10 ohms or more to 75 ohms or less, 10 ohms or more to 50 ohms or less, 10 ohms or more to 25 ohms or less, 25 ohms or more to 100 ohms or less, 25 ohms or more to 75 ohms or less, 25 ohms or more to 50 ohms or less, 50 ohms or more to 100 ohms or less, or even 50 ohms or more to 75 ohms or less, or any and all subranges formed by any of these endpoints.

[0140] In the embodiments, the overall article can have any suitable bulk density. As used herein, "bulk density" refers to the mass of the article divided by the total volume occupied by the article. The total volume occupied by the article includes the particle volume, the interparticle void volume, and the internal pore volume (i.e., voids within the particles), but excludes longitudinal channels (e.g., the portion of the article considered to be an open front area when viewed from the longitudinal end of the article). The total volume occupied by an article with a honeycomb structure can be defined as the ratio of the portion of the article considered to be a closed front area (CFA) to the portion considered to be an open front area (OFA) when viewed from the longitudinal end of the article, with CFA and OFA given as complementary percentages summing to 100%. Specifically, OFA corresponds to the portion of the cross-sectional area occupied by the open channels of the honeycomb structure of the article, while CFA corresponds to the remaining portion occupied by the intersecting matrix. In the embodiments, the bulk density of the overall article can be greater than or equal to 0.5 g / cm³. 3 And less than or equal to 1.5 g / cm 3≥0.5 g / cm 3 And less than or equal to 1.25 g / cm 3 ≥0.5g / cm 3 And less than or equal to 1.0 g / cm³ 3 ≥0.75 g / cm 3 And less than or equal to 1.5 g / cm 3 ≥0.75 g / cm 3 And less than or equal to 1.25 g / cm 3 ≥0.75 g / cm 3 And less than or equal to 1.0 g / cm³ 3 ≥1.0 g / cm 3 And less than or equal to 1.5 g / cm 3 or even greater than or equal to 1.0 g / cm³ 3 And less than or equal to 1.25 g / cm 3 Or any and all subranges formed by any of these endpoints.

[0141] In the embodiments, the OFA of the overall article can be greater than or equal to 60% and less than or equal to 90%, greater than or equal to 60% and less than or equal to 80%, greater than or equal to 70% and less than or equal to 90%, or even greater than or equal to 70% and less than or equal to 80%, or any and all subranges formed by any of these endpoints.

[0142] In embodiments, the integral article can have any suitable total pore volume (i.e., porosity). In embodiments, the total pore volume of the integral article can be greater than or equal to 40% and less than or equal to 95%, greater than or equal to 40% and less than or equal to 85%, greater than or equal to 40% and less than or equal to 75%, greater than or equal to 40% and less than or equal to 65%, greater than or equal to 50% and less than or equal to 95%, greater than or equal to 50% and less than or equal to 85%, greater than or equal to 50% and less than or equal to 75%, greater than or equal to 50% and less than or equal to 65%, greater than or equal to 60% and less than or equal to 95%, greater than or equal to 60% and less than or equal to 75%, or even greater than or equal to 70% and less than or equal to 75%, or any and all sub-ranges formed by any of these endpoints.

[0143] In embodiments, the monolithic article may include a coating located on a core. The coating may be continuous or discontinuous. The coating may include a catalyst (e.g., a catalyst used in a catalytic converter to treat exhaust emissions or other catalysts), an adsorbent for adsorbing and desorbing CO2, or a combination thereof. The adsorbent may include zeolite, sodium carbonate, activated carbon, carbon nanotubes, metal-organic frameworks (MOFs), amines, or combinations thereof. In embodiments, the coating may be directly adhered to the monolithic article, wherein the monolithic article does not contain any intermediate adhesive layer between the coating and the article. In other embodiments, the monolithic article may include an adhesive layer, such as a carrier coating material. The adhesive layer may include a deposition of high surface area particles (e.g., γ-alumina, zeolite, activated carbon, or combinations thereof).

[0144] In embodiments, a method of using an integral article having a coating including the adsorbent described herein includes: exposing the article to a gas stream containing CO2 to adsorb at least a portion of the CO2 in the gas stream into the coating; and desorbing CO2 from the coating, said desorption comprising applying a potential across the article to heat the article. In embodiments, desorbing CO2 from the coating on the integral article includes heating the integral article, such as by resistance heating, conveying hot gas (e.g., steam) through the integral article, microwave heating, induction heating, through an external heat source at the periphery of the integral article, or a combination thereof. In embodiments, desorbing CO2 from the coating may include encapsulating the CO2, such as placing the CO2 in a storage tank.

[0145] In other embodiments, a method of using an integral article having a coating including a catalyst as described herein may include exposing the integral article to a gas stream to catalyze a chemical reaction of one or more components in the gas stream using the catalyst.

[0146] Example

[0147] To make the various embodiments easier to understand, reference is made to the following examples, which are intended to illustrate various embodiments of the overall article of manufacture described herein.

[0148] Table 1 below shows the sources of the components used to form the example extrudable compositions E1 and E2. Table 2 below shows the example extrudable compositions E1 and E2, wherein methylcellulose, starch, mineral oil and water are given as additional amounts relative to 100 parts of inorganic matter based on the total dry weight of the extrudable compositions, and all other components are given as weight percentages (%).

[0149] Table 1

[0150]

[0151] Table 2

[0152]

[0153] Now for reference Figure 3-5 The shrinkage and expansion curves of the honeycomb extrusions formed from the example extrudable composition under heating in the presence of N2 (i.e., a relatively low oxygen content) and in air (i.e., a relatively high oxygen content) are shown. Figure 3 and 4 ) and relative mass change and heat flow ( Figure 5 The relationship between temperature and extrusion weight loss is shown in Table 3 below at different points for each atmosphere condition. Figure 3-5 As shown in Table 3, the extrudate did not change significantly before approximately 400°C for both N2 and air conditions. For temperatures between 400°C and 600°C, shrinkage was approximately the same for both N2 and air conditions and can be attributed to clay shrinkage. Between 600°C and 1000°C, there was a difference in shrinkage between N2 and air conditions, which can be attributed to shrinkage associated with graphite removal. Shrinkage was also observed under N2 conditions, which can be attributed to the endothermic reaction of talc and the softening of hollow glass beads. Between 400°C and 900°C, there was a difference in the percentage of weight loss between N2 and air conditions, which can be mainly attributed to weight losses associated with organic coke and graphite removal in the presence of O2.

[0154] Table 3

[0155]

[0156] like Figure 3-5 As illustrated in Table 3, prolonged exposure to temperatures above 650°C in the presence of O2 leads to increased graphite oxidation. Therefore, to limit graphite oxidation, the method described herein involves degreasing at a degreasing temperature below 650°C and sintering at a sintering temperature greater than or equal to 650°C in a sintering atmosphere with an oxygen concentration less than or equal to 2.5%.

[0157] Now for reference Figure 6-8 The 5 cm × 15 cm honeycomb extruded material formed from the example extrudable composition E1 was fired in a small-scale chamber kiln using electric heating and a simulated atmosphere.

[0158] Now for reference Figure 6 Two honeycomb extrusions, H1 and H2, were degreased between 250°C and 600°C in an atmosphere of 8% O2 to remove the binder from the extrusions. Then, the honeycomb extrusions H1 and H2 were sintered between 600°C and 900°C in an atmosphere maintained at 8% O2 (H1) or reduced to 0.5% O2 (H2). Figure 6 As shown, the weight loss and shrinkage of the honeycomb extrudate H2 are relatively small under 0.5% O2 conditions. Figure 6As illustrated, graphite can be preserved under relatively low O2 conditions (e.g., oxygen concentration less than or equal to 2.5%).

[0159] Now for reference Figure 7 Two honeycomb extrusions, H3 and H4, were degreased at 250°C in 8% O2 for 4 hours. Then, H3 and H4 were sintered at 875°C in an atmosphere of approximately 0.5-1% O2 for 2 hours (H3) or 4 hours (H4). Figure 7 As shown, there is a difference in shrinkage rate in two directions between the two conditions. Figure 7 As illustrated, weight loss and shrinkage can occur even under relatively low O2 conditions due to sintering and removal of graphite from the outer skin and / or softening of the hollow glass beads. Therefore, controlling the holding time can ensure the desired degreasing and graphite removal.

[0160] Now for reference Figure 8 The honeycomb extrusion H5 was degreased at 250°C in 8% O2 for 4 hours. Then, the honeycomb extrusion H5 was sintered at 875°C in an atmosphere of approximately 0.5-1% O2 for 4 hours. Figure 8 As shown, at 250°C, there was an initial decrease of 18% in extrudate weight loss. After a holding period of 4 hours, the weight loss increased from 18% to 20%. Figure 8 As illustrated, controlling O2 and degreasing duration can ensure the desired degreasing and graphite removal.

[0161] Now for reference Figure 9 The honeycomb extrudate H6 formed from the example extrudable composition E2 was degreased at up to 600°C in an atmosphere of 7.5% O2. Then, the honeycomb extrudate H6 was sintered between 600°C and 900°C in an atmosphere of about 1.5% O2. Figure 9 As shown, it takes approximately 5 hours for the coke to burn completely, as indicated by the "first bulge" at H6 temperature at approximately 7 hours and the "second bulge" at H6 temperature at approximately 12 hours. Now refer to... Figure 10 Graphite was removed from the outer skin (white) of the honeycomb article A6 formed from honeycomb extrusion H6.

[0162] Now for reference Figure 11-16 The honeycomb extruded H7 formed from the example extrudable composition was degreased at up to 600°C in an atmosphere of 7.5% O2, and sintered between 600°C and 900°C in an atmosphere of about 1.5% O2. Figure 11-16 As shown, graphite is retained in the core of the resulting honeycomb article A7, where graphite has been removed from the outer skin.

[0163] The honeycomb extruded material H8, formed from the example extrudable composition E2, was degreased and sintered. Referring now to Table 4, the porosity, MOR, Young's modulus, and the difference between MOR and Young's modulus (i.e., ((outer skin value - core value) / core value)) of the resulting honeycomb article A8 are shown. As shown in Table 4, the rupture modulus of the outer skin is 163% greater than that of the core. As illustrated in Table 4, controlling the temperature and / or atmosphere during degreasing and sintering resulted in a conductive integral article with improved mechanical strength.

[0164] Table 4

[0165]

[0166] Referring now to Table 5, the honeycomb extrusions H9 to H12 formed from example compositions E3 and E2 were subjected to degreasing and sintering conditions as shown in Table 5. Table 5 shows the resistance of the cores of the resulting honeycomb articles A9 to A12. As illustrated in Table 5, controlling the temperature and / or atmosphere during degreasing and sintering produced conductive integral articles.

[0167] Table 5

[0168]

[0169] 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. Therefore, this specification is intended to cover modifications and variations to the various embodiments described herein, provided that such modifications and variations fall within the scope of the appended claims and their equivalents.

Claims

1. A method for forming an integral article, the method comprising: An extrudable composition is extruded to form an extrudate, the extrudable composition comprising a binder, inorganic particles and graphite particles, the extrudate comprising an outer skin and a core disposed within the outer skin; Dry the extrudate; The extrudate is degreased in a degreasing atmosphere at one or more degreasing temperatures to remove the binder from the extrudate, wherein the one or more degreasing temperatures are below 650°C; and The extrudate is sintered in a sintering atmosphere at one or more sintering temperatures to remove the graphite particles from the outer skin of the extrudate and sinter the inorganic particles of the extrudate, thereby forming the integral article, wherein the one or more sintering temperatures are greater than or equal to 650°C and the oxygen concentration of the sintering atmosphere is less than or equal to 2.5%.

2. The method according to claim 1, wherein the oxygen concentration of the sintering atmosphere is greater than or equal to 0.0% and less than or equal to 2.5%.

3. The method according to claim 1 or claim 2, wherein the one or more degreasing temperatures are greater than or equal to 200°C and less than 650°C.

4. The method according to any one of claims 1 to 3, wherein the degreasing comprises holding the extrudate at a degreasing temperature and in the degreasing atmosphere for more than or equal to 2 hours and less than or equal to 40 hours.

5. The method of claim 4, wherein the degreasing comprises increasing the temperature in the degreasing atmosphere to one of the one or more degreasing temperatures at a first variable rate greater than or equal to 5°C / hour and less than or equal to 20°C / hour.

6. The method according to any one of claims 1 to 5, wherein the oxygen concentration of the degreasing atmosphere is greater than or equal to 3% and less than or equal to 18%.

7. The method according to any one of claims 1 to 6, wherein the one or more sintering temperatures are greater than or equal to 650°C and less than or equal to 1000°C.

8. The method according to any one of claims 1 to 7, wherein the sintering comprises holding the extrudate at a holding sintering temperature and in the sintering atmosphere for a period of 0.5 hours to 8 hours.

9. The method of claim 8, wherein the sintering comprises increasing to the holding sintering temperature at a second sloping rate greater than or equal to 5°C / hour and less than or equal to 100°C / hour.

10. The method according to any one of claims 1 to 9, wherein at least one of the degreasing atmosphere and the sintering atmosphere comprises nitrogen, argon, or a combination thereof.

11. The method according to any one of claims 1 to 10, wherein the adhesive comprises an organic adhesive, the organic adhesive comprising cellulose, cellulose derivatives, polymers, thermosetting resins, or combinations thereof.

12. The method according to any one of claims 1 to 11, wherein the inorganic particles comprise borates, phosphates, transition metal oxides, oxides, hydroxides, carbonates, silicates, aluminosilicates, or combinations thereof.

13. The method of claim 12, wherein the inorganic particles comprise talc, clay, MgO, alumina, or a combination thereof.

14. The method according to any one of claims 1 to 13, wherein the graphite particles comprise graphite plates, graphite sheets, natural graphite, synthetic graphite, or combinations thereof.

15. The method according to any one of claims 1 to 14, wherein the extrudable composition further comprises a pore-forming material comprising starch, nut shell powder, carbon, natural polymers, synthetic polymers, carbonaceous materials, crystalline carbon, amorphous carbon, or combinations thereof.

16. The method according to any one of claims 1 to 15, wherein the extrudable composition further comprises a porous material, said porous material comprising paper, polymer, glass, glass ceramic, ceramic, diatomaceous earth, perlite, pumice, or a combination thereof.

17. The method of claim 16, wherein the porous material comprises hollow glass beads.

18. The method according to any one of claims 1 to 17, wherein the core has a honeycomb structure shape, the honeycomb structure comprising a plurality of cells defining parallel channels running longitudinally through the honeycomb structure.

19. An integral article comprising: The outer skin, said outer skin comprising inorganic material; and The core, disposed within the outer skin, comprises a continuous graphite phase and an inorganic phase containing the inorganic material, wherein the graphite phase and the inorganic phase together form an interconnected porous structure, wherein: As measured according to ASTM-D6272, the fracture modulus of the outer skin is at least 150% greater than that of the core; and The overall article is conductive.

20. The integral article of claim 19, wherein the outer skin contains no or substantially no graphite.

21. The integral article of claim 19 or claim 20, wherein the continuous graphite phase is uniformly distributed throughout the core.

22. The integral article of any one of claims 19 to 21, wherein the core has a honeycomb structure shape, the honeycomb structure comprising a plurality of units defining parallel channels extending longitudinally through the honeycomb structure.

23. The integral article according to any one of claims 19 to 22, wherein the continuous graphite phase comprises calcined graphite plates, graphite sheets, natural graphite, synthetic graphite, or combinations thereof.

24. The integral article according to any one of claims 19 to 23, wherein the inorganic material comprises borates, phosphates, transition metal oxides, oxides, hydroxides, carbonates, silicates, aluminosilicates, or combinations thereof.

25. The integral article of claim 24, wherein the inorganic material comprises talc, clay, MgO, alumina, or a combination thereof.

26. The integral article according to any one of claims 19 to 25, wherein, as measured according to ASTM C623, the Young's modulus of the outer skin is at least 50% greater than that of the core.

27. The integral article of any one of claims 19 to 26, wherein the resistance of the core of the integral article is greater than or equal to 1 ohm and less than or equal to 100 ohms.

28. The integral article of any one of claims 19 to 27, wherein the integral article comprises a coating located on the core, the coating comprising a catalyst, an adsorbent for adsorbing and desorbing CO2, or a combination thereof.

29. A method of using the article of claim 28, the method comprising: The article is exposed to a gas stream containing CO2 to adsorb at least a portion of the CO2 in the gas stream into the adsorbent in the coating.

30. The method of claim 29, further comprising: The CO2 is desorbed from the coating.

31. The method of claim 30, wherein the desorption comprises applying a potential across the article to heat the article.

32. A method for forming a porous conductive article, the method comprising: A precursor comprising a precursor composition is heated in a first heating atmosphere within a first atmosphere temperature range. The precursor composition comprises inorganic particles, one or more organic components, and a conductive filler material. The first atmosphere temperature range is lower than the combustion temperature of the conductive filler material. The precursor comprises a core surrounded by a periphery having the same precursor composition. The precursor is heated in the first heating atmosphere at one or more first atmosphere temperatures within the first atmosphere temperature range, and The heating in the first heating atmosphere is carried out for a first heating duration and at one or more first atmosphere temperatures, wherein the first heating duration and the one or more first atmosphere temperatures are sufficient to remove the organic component from the precursor while the conductive filler material in the precursor remains intact; and The precursor is heated in a second heating atmosphere within a second atmosphere temperature range, the second atmosphere temperature range including one or more second atmosphere temperatures equal to or higher than the combustion temperature of the conductive filler material. The second heating atmosphere has a gas composition that prevents the conductive filler material from burning. The heating in the second heating atmosphere is carried out for a second heating duration and at one or more second atmosphere temperatures, the second heating duration and the one or more second atmosphere temperatures being sufficient to remove at least a portion of the conductive filler material from the periphery of the precursor, while the conductive filler material remains intact in the core of the precursor.

33. The method of claim 32, wherein heating the precursor in the second heating atmosphere is sufficient to sinter the inorganic material in the outer periphery of the precursor.

34. The method of claim 32 or claim 33, wherein the strength of the periphery is greater than the strength of the core.

35. The method according to any one of claims 32 to 34, wherein heating the precursor in the first heating atmosphere increases the porosity in the precursor.

36. The method according to any one of claims 32 to 35, wherein the average thickness of the outer periphery is less than 10% of the transverse hydraulic diameter of the precursor.

37. The method according to any one of claims 32 to 36, wherein the precursor comprises a honeycomb structure, the honeycomb structure comprising intersecting walls extending in an axial direction, the intersecting walls forming a plurality of parallel units in a transverse plane.

38. The method according to any one of claims 32 to 37, wherein the gas composition in the second heating atmosphere that prevents the combustion of the conductive filler material is provided by: adjusting the oxygen input and / or level in the second atmosphere; adjusting the fuel mixture of one or more burners that provide heat to the second atmosphere; adjusting the introduction and / or level of recirculated combustion gas products in the second atmosphere; adjusting the introduction and / or level of inert gas in the second atmosphere; or a combination thereof.

39. The method of claim 38, wherein the fuel mixture of the one or more burners is a lean fuel mixture.

40. The method according to claim 38 or claim 39, wherein the inert gas is nitrogen, argon, or a combination thereof.

41. The method according to any one of claims 32 to 40, further comprising: extruding the extrudable composition to form an extrudate; and cutting a portion of the extrudate.

42. The method of claim 41, wherein the core and the periphery of the precursor are extruded simultaneously.

43. The method according to any one of claims 32 to 42, wherein the first atmosphere temperature range is greater than or equal to 200°C and less than or equal to 650°C.

44. The method according to any one of claims 32 to 43, wherein the oxygen content of the second atmosphere is within a second oxygen range of greater than or equal to 0.0% and less than or equal to 2.5%.

45. The method according to any one of claims 32 to 44, wherein the oxygen content of the first atmosphere is within a first oxygen range of greater than or equal to 3% and less than or equal to 18%.

46. ​​The method according to any one of claims 32 to 45, wherein the first heating duration is greater than or equal to 2 hours and less than or equal to 10 hours.

47. The method according to any one of claims 32 to 46, wherein the second heating duration is greater than or equal to 0.5 hours and less than or equal to 8 hours.

48. The method according to any one of claims 32 to 47, wherein the precursor further comprises hollow glass beads.

49. The method of claim 48, wherein the hollow glass beads are softened when the precursor is heated in the second heating atmosphere.

50. The method according to claim 48 or claim 49, wherein the hollow glass bead is a hollow glass microsphere.

51. The method according to any one of claims 32 to 50, wherein the precursor further comprises one or more porous materials, said porous materials comprising paper, polymer, glass, glass ceramic, ceramic, diatomaceous earth, perlite, pumice, or combinations thereof.

52. The method according to any one of claims 32 to 51, wherein the organic component comprises one or more starches, one or more binders, one or more oils, one or more volatile organic compounds, or combinations thereof.

53. The method of claim 52, wherein one or more adhesives are cellulose adhesives.

54. The method according to any one of claims 32 to 53, wherein the precursor is integral, and wherein the core and the periphery are made of the same composition.

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