SHAPED BODY, COMPOSITE BODY, METHOD FOR PRODUCING A SHAPED BODY AND METHOD FOR PRODUCING A COMPOSITE BODY

Abstract

In order to provide a shaped body which has good high-temperature resistance, to which a coating material adheres permanently, and which is easy to produce, a shaped body is proposed which has a channel structure formed by shaping a material of the shaped body and a pore structure in the material of the shaped body, wherein the material of the shaped body comprises a particulate base material or is formed therefrom at least in part, wherein the base material comprises a cordierite material and/or a mullite material, wherein particles of the base material are connected to one another directly and/or indirectly, and wherein approximately 5 vol. % of a coating material or more, based on a total volume of the pore structure, can be or is absorbed into pores of the pore structure.

Claims

1. Shaped body (100), in particular as a carrier body for a coating material (102), the shaped body (100) comprising the following: a channel structure (106) which is formed by shaping a material of the shaped body (100); and a pore structure (110) in the material of the shaped body (100), wherein the material of the shaped body (100) comprises a particulate base material or is formed therefrom at least in part, wherein the base material comprises a cordierite material and/or a mullite material, wherein particles of the base material are connected to one another directly and/or indirectly, wherein approximately 5 vol. % of a coating material (102) or more, based on a total volume of the pore structure (110), can be or is absorbed into pores of the pore structure (110).

2. Shaped body (100) according to claim 1, characterized in that the material of the shaped body (100) comprises a binding material (112) by means of which particles of the base material are connected to one another, in particular integrally, the binding material (112) in particular comprising one or more of the following materials or being formed therefrom: one or more transition metal oxides, in particular titanium dioxide; one or more aluminum oxides; one or more alkaline earth metal oxides, in particular magnesium oxide; and one or more silicates.

3. Shaped body (100) according to either claim 1 or claim 2, characterized in that a porosity of the pore structure (110) is approximately 35% to approximately 54%, in particular approximately 43% to approximately 46%, and/or in that an average pore diameter of the pores of the pore structure (110) is approximately 7 m to approximately 20 m, more preferably approximately 10 m to approximately 16 m.

4. Shaped body (100) according to any of claims 1 to 3, characterized in that the shaped body (100) has a mass concentration of approximately 450 g/l or less, in particular approximately 360 g/l or less.

5. Composite body (104) comprising a shaped body (100) according to any of claims 1 to 4 and a coating material (102).

6. Composite body (104) according to claim 5, characterized in that the coating material (102) extends into pores of the pore structure (110) of the shaped body (100) in a coated state of the shaped body (100) and/or in that the coating material (102) is chemically and/or physically connected to the material of the shaped body (100).

7. Composite body (104) according to either claim 5 or claim 6, characterized in that one or more components and/or substances and/or materials are contained in the same chemical composition and/or in chemically identical form both in the material of the shaped body (100) and in the coating material (102).

8. Composite body (104) according to any of claims 5 to 7, characterized in that the coating material (102) comprises one or more of the following materials or is formed therefrom: titanium dioxide, vanadium oxide, in particular vanadium (V) oxide, tungsten oxide, in particular tungsten (VI) oxide.

9. Method for producing a shaped body (100), in particular a shaped body (100) according to any of claims 1 to 4, wherein the method comprises the following: providing a mixture comprising a particulate base material which is pre-fired and/or ground up and which comprises a cordierite material and/or a mullite material or is formed therefrom; producing a preform by shaping the mixture, wherein in particular a channel structure (106) is formed; and firing the preform, so that particles of the base material are connected to one another directly and/or indirectly, wherein a shaped body (100) is formed, wherein the shaped body (100) has a pore structure (110), wherein approximately 5 vol. % of a coating material (102) or more, based on a total volume of the pore structure (110), can be absorbed into pores of the pore structure (110).

10. Method according to claim 9, characterized in that the mixture comprises one or more precursors of a binding material (112) and in that the particles of the base material are taken up by the binding material (112) by chemical and/or physical reaction of the one or more precursors to the binding material (112) and/or are connected to one another by the binding material (112).

11. Method according to either claim 9 or claim 10, characterized in that an average grain size of the particles of the base material is greater by a factor of 2 or more than a grain size of one or more precursors which, by firing, form a binding material (112) of the material of the shaped body (100).

12. Method according to any of claims 9 to 11, characterized in that the mixture comprises a pore-forming material, in particular the pore-forming material comprising one or more of the following materials or being formed therefrom: potato starch, graphite, coconut flour, acrylic glass, acrylate.

13. Method according to claim 12, characterized in that the proportion of the pore-forming material is approximately 5 wt. % or more, in particular approximately 10 wt. % or more, based on a total mass of the mixture.

14. Method according to any of claims 9 to 13, characterized in that the mixture comprises one or more precursors which react to form a binding material (112) by means of which particles of the base material are connected to one another, the binding material (112) in particular comprising one or more of the following materials or being formed therefrom: one or more transition metal oxides, in particular titanium dioxide; one or more aluminum oxides; one or more alkaline earth metal oxides, in particular magnesium oxide; and one or more silicates.

15. Method for producing a composite body (104), in particular a composite body (104) according to any of claims 5 to 8, wherein the method comprises the following: providing a shaped body (100), in particular a shaped body (100) according to any of claims 1 to 4; applying a coating material mixture to the shaped body (100), wherein the coating material mixture comprises a coating material (102) and a liquid or is formed therefrom; and firing the shaped body (100) and the coating material mixture applied thereto, so that the coating material (102) forms a coating on the shaped body (100), wherein approximately 5 vol. % of the coating material (102) or more, based on a total volume of the pore structure (110), is absorbed into pores of a pore structure (110) in a material of the shaped body (100).

Description

[0164] In the drawings:

[0165] FIG. 1 is a first scanning electron microscope image of a section through a wall of an embodiment of a shaped body in an uncoated state;

[0166] FIG. 2 shows a comparison of a scanning electron microscope image of a section through a wall of a shaped body and an EDX mapping of the same region;

[0167] FIG. 3 is a scanning electron microscope image of an embodiment of a composite body, where a shaped body has been coated with a coating material, in a section perpendicular to a main extension direction of a channel of the shaped body; and

[0168] FIG. 4 is a scanning electron microscope image of the composite body from FIG. 3 magnified 800 times.

[0169] The same or functionally equivalent elements are provided with the same reference signs in all figures.

[0170] An embodiment shown in FIG. 1 of a shaped body, designated as a whole by 100, preferably forms a carrier body for a coating material 102 (cf. FIGS. 3 and 4). The shaped body 100 and the coating material 102 together form a composite body 104 in a coated state of the shaped body 100.

[0171] The shaped body 100 can have dimensions of up to 450 mm in all spatial directions.

[0172] The shaped body 100 preferably has cavities which are arranged regularly by shaping a material of the shaped body 100 and through which a channel structure 106 of the shaped body 100 is formed.

[0173] The channel structure 106 is preferably a macroscopic channel structure.

[0174] The shaped body 100 preferably forms a honeycomb body which has channels with an at least approximately square cross section.

[0175] FIG. 1 shows a scanning electron microscope (SEM) image through a wall 108 of the channel structure 106 of the shaped body 100. The SEM image was captured with a backscattered electron detector at an acceleration voltage of 15.00 kV and shows the wall 108 of the channel structure 106 of the shaped body 100 magnified 500 times.

[0176] A wall thickness of the wall 108 of the channel structure 106 of the shaped body 100 is preferably approximately 150 m or more, in particular approximately 200 m or more. In particular, the wall thickness of the wall 108 is approximately 500 m or less, for example approximately 300 m or less.

[0177] A wall thickness of 290 m has proven to be a particularly preferred wall thickness.

[0178] The wall thickness is preferably an average wall thickness.

[0179] It may be favorable if the shaped body 100 comprises 100 or 150 cells per square inch.

[0180] In addition to the channel structure 106 formed by shaping the material of the shaped body, the shaped body 100 has a pore structure 110 which is formed in the material of the shaped body 100.

[0181] The pore structure 110 is preferably a microscopic pore structure.

[0182] The pores of the pore structure 110 are shown darker than the material of the shaped body 100 in all of the SEM images.

[0183] A porosity of the pore structure 110 is preferably approximately 35% or more, in particular approximately 43% or more.

[0184] In particular, the porosity of the pore structure 110 is approximately 54% or less, in particular approximately 46% or less.

[0185] Porosity is preferably understood to mean a ratio of a cavity volume and a total volume of the pore structure 110. Cavities formed by shaping the material to form the channel structure 106 are excluded from the overall volume of the pore structure 110.

[0186] An average pore diameter of the pores of the pore structure 110 of the shaped body 100 is preferably approximately 10 m or more, in particular approximately 12 m or more.

[0187] In particular, the average pore diameter of the pore structure 110 of the shaped body 100 is approximately 20 m or less, for example approximately 16 m or less.

[0188] The porosity of the pore structure 110 is preferably an open porosity. The coating material 102 can thus penetrate into pores of the pore structure 110 of the shaped body 100 during the production of the composite body 104.

[0189] A mass concentration and/or density of the shaped body 100 is preferably approximately 300 g/l or more and/or approximately 450 g/l or less. For example, the mass concentration and/or bulk density plus cavities of the shaped body 100 formed by the channel structure is approximately 350 g/l.

[0190] As can be seen in particular in FIG. 1, outer surfaces of the walls 108 of the channel structure 106 of the shaped body 100 have a rough surface.

[0191] For example, a so-called extrusion skin of the shaped body 100 is designed to be rough and/or spatially structured.

[0192] The material of the shaped body 100 preferably comprises base material which comprises a cordierite material and/or a mullite material or is formed therefrom.

[0193] The base material of the material of the shaped body 100 is preferably in powder form and/or particulate.

[0194] It may be advantageous if particles of the base material are connected to one another, in particular integrally, by means of a binding material 112 and/or are bonded to one another by means of the binding material 112.

[0195] The particles of the base material are preferably surrounded by the binding material 112 in the shaped body 100 (cf. FIG. 4).

[0196] In order to produce the shaped body 100, a mixture is preferably provided or produced which is shaped into a preform and then fired in a rapid firing process.

[0197] The mixture preferably comprises the base material and precursors of the binding material 112.

[0198] It may be advantageous if titanium dioxide, one or more aluminum oxides, one or more magnesium oxides, one or more silicates and aluminum hydroxide are used as precursors of the binding material 112.

[0199] For example, one or more of the following materials are used as precursors for the binding material: titanium dioxide, a plurality of aluminum oxides, one or more kaolins, magnesium oxide, kaolin chamotte, aluminum hydroxide, one or more silicates.

[0200] Magnesium silicates, for example a product of the Finntalc series from Mondo Minerals B.V., 1041 AR Amsterdam, Netherlands, are also suitable as silicates.

[0201] As aluminum oxides, the following are particularly well suited, for example: [0202] the product NABALOX NO 715-10 from Nabaltec AG, 92409 Schwandorf; [0203] one of the products in the aluminum oxide CT series from GPO GmbH, 77694 Kehl.

[0204] It may be advantageous if a proportion of the one or more precursors of the binding material 112 is approximately 10 wt. % or more and/or approximately 35 wt. % or less, based on a total mass of the mixture.

[0205] In embodiments in which titanium dioxide is used, a proportion of the titanium dioxide is preferably approximately 1 wt. % or more and/or approximately 5 wt. % or less, based on the total mass of the binding material 112 or based on the total mass of the mixture.

[0206] It may be advantageous if the mixture contains a pore-forming material in addition to the base material and the precursors of the binding material.

[0207] The pore-forming material is used in particular to form pores in the material of the shaped body 100.

[0208] The pore-forming material is added, for example, before and/or during the formation of the preform.

[0209] It may be favorable if the pore-forming material comprises one or more of the following materials or is formed therefrom: potato starch, graphite, coconut flour, acrylic glass, acrylate.

[0210] A proportion of the pore-forming material is preferably approximately 5 wt. % or more and/or approximately 20 wt. % or less, based on the total mass of the mixture.

[0211] As already described, the base material is preferably in the form of a powder and/or particulate.

[0212] A grain size distribution (particle size distribution) of the particles of the cordierite material and/or the mullite material is preferably as follows: [0213] d.sub.10 approximately 1 m or more and/or approximately 3 m or less, for example 2 m; and/or [0214] d.sub.50 approximately 10 m or more and/or approximately 28 m or less, for example approximately 18 m; and/or [0215] d.sub.90 approximately 30 m or more and/or approximately 40 m or less, for example 35 m.

[0216] A d.sub.10 value is understood to mean the particle size below which 10% of the particles of the relevant substance fall, while 90% of the particles of the relevant substance are larger than the d.sub.10 value.

[0217] A d.sub.50 value is understood to mean the particle size below which 50% of the particles of the relevant substance fall, while 50% of the particles of the relevant substance are larger than the d.sub.50 value.

[0218] A d.sub.90 value is understood to mean the particle size below which 90% of the particles of the relevant substance fall, while 10% of the particles of the relevant substance are larger than the d.sub.90 value.

[0219] Comparatively coarse-grained cordierite material and/or mullite material is preferably used as the base material. Overall, an average grain size of the particles of the cordierite material and/or mullite material used in the base material is approximately 100 m or less, for example.

[0220] In order to produce the base material, the cordierite material and/or the mullite material are preferably fired, for example calcined. After a firing process, the cordierite material and/or the mullite material are preferably ground up and sieved, for example.

[0221] According to a preferred embodiment, cordierite material and no mullite material is used in or as the base material.

[0222] Alternatively, a proportion of approximately 10 wt. % or less of mullite material, based on a total mass of the base material, can be used. A proportion of the cordierite material is then in particular approximately 90 wt. %, based on the total mass of the base material.

[0223] It has already been described that a preform is preferably first formed from the mixture used to produce the shaped body 100. This is preferably carried out by pressing and/or extrusion. This produces in particular the channel structure 106 of the shaped body 100.

[0224] After shaping, the preform is preferably dried, for example by means of microwave heating in a continuous furnace.

[0225] The preform is then preferably fired, as a result of which the shaped body 100 is formed. The firing is preferably carried out in a rapid firing continuous furnace. A pushing speed ranges from approximately 3 cm/min to approximately 10 cm/min, for example.

[0226] The shaped body 100 is preferably produced in a rapid firing process in which a preform is fired with a temperature gradient of more than 2300 C., in particular more than 2200 K/m and/or more than 2200 K/h, for example in the range between approximately 120 C. and approximately 2000 C.

[0227] The shaped body 100 is preferably produced when the preform is fired at temperatures of at most approximately 1400 C. In this way, it is possible to connect the particles of the base material to one another while maintaining the particle property.

[0228] The preform is preferably fired at a temperature of approximately 1300 C., as a result of which the shaped body 100 is formed.

[0229] It may be favorable if the preform is fired in a firing cycle lasting at least approximately 300 minutes and/or at most approximately 480 minutes, for example approximately 430 minutes to approximately 450 minutes.

[0230] The duration of the firing cycle is understood to mean the time between the start of the firing process of the preform and the end of the firing process, in particular when the shaped body 100 formed during the firing process is removed from a furnace. In particular, this is understood to mean the length of time between the start of the firing process and the cooling of the fired shaped body 100.

[0231] When the preform is fired, the one or more non-pre-fired precursors of the binding material 112 preferably react, for example to form a cordierite material and other substances, while particles of the base material are only superficially melted and/or react with the components of the binding material only on their surface 112.

[0232] Preferably, approximately 70 vol. % or more of the particles of the base material remain chemically and/or physically unchanged, particularly in an interior of the particles.

[0233] As already mentioned, the resulting shaped body 100 preferably forms a carrier body for the coating material 102 (cf. FIGS. 3 and 4).

[0234] In order to produce the composite body 104, the coating material 102 is applied to and/or on the shaped body 100, for example by means of dip coating.

[0235] For adhesion of the coating material 102 and/or a connection of the material of the shaped body 100 and the coating material 102, it can be advantageous if the coating material 102 has one or more substances and/or components and/or materials which are also contained in the same chemical composition and/or in chemically identical form in the material of the shaped body 100.

[0236] According to a preferred embodiment, titanium dioxide is used both as a precursor of the binding material 112 and as a component of the coating material 102.

[0237] The presence of the titanium dioxide in the shaped body can be seen from the comparison shown in FIG. 2 of an SEM image and an EDX (energy dispersive X-ray spectroscopy) mapping of the same region.

[0238] FIG. 2 shows an SEM image on the left, which was captured with 1500 magnification and an acceleration voltage of 15.00 kV. A backscattered electron detector was used.

[0239] The SEM image shows that dark particles are absorbed in a lighter material. These dark particles are the particles of the base material, which also continue to have particle properties in the fired shaped body 100. The lighter material surrounding the particles is the binding material 112.

[0240] Inclusions shown in white can be seen in the lighter material. These inclusions comprise titanium, because a signal at energy characteristic of titanium is detected in the EDX (energy dispersive X-ray spectroscopy) mapping of the same region shown on the right. Since titanium was contained exclusively in titanium dioxide in the starting materials, it can be assumed that the white inclusions are made of titanium dioxide.

[0241] The correlation is indicated by arrows.

[0242] The material has an overall porosity, with cavities being shown comparatively dark.

[0243] The use of titanium dioxide both in the material of the shaped body 100 and in the coating material 102 improves the interaction thereof. This can be seen from FIGS. 3 and 4.

[0244] The coating material 102 shown in FIGS. 3 and 4 preferably comprises titanium dioxide and/or vanadium oxide, in particular vanadium (V) oxide, and/or tungsten oxide, in particular tungsten (VI) oxide.

[0245] FIGS. 3 and 4 are SEM images of a section through the shaped body 100 coated with the coating material 102. The acceleration voltage for the images is 12.50 kV in each case.

[0246] The image shown in FIG. 3 was taken with 110 magnification and shows a honeycomb of the shaped body 100. The coating material 102 is applied to an inner side facing the cavity.

[0247] FIG. 4 shows the transition between the coating material 102 and the wall 108 of the shaped body 100 at 800 magnification.

[0248] A backscattered electron detector was used both for the image in FIG. 3 and for the image shown in FIG. 4.

[0249] FIG. 4 clearly shows that approximately 5 vol. % or more, in particular approximately 10 vol. % of the coating material 102 or more, based on a total volume of the pore structure 110, is absorbed into pores of the pore structure 110 of the shaped body 100. The material contrast with which the coating material 102 is shown can also be seen within the pores.

[0250] According to a preferred composition, the coating material 102 comprises the following materials or is formed therefrom: titanium dioxide, vanadium (V) oxide and tungsten (VI) oxide.

[0251] A proportion of the titanium dioxide in the coating material 102 is preferably approximately 80 wt. % or more, based on a total mass of the coating material 102.

[0252] For example, a mixture containing approximately 88 wt. % to approximately 93 wt. % titanium dioxide, approximately 0.5 wt. % to approximately 3 wt. % vanadium (V) oxide, for example approximately 2 wt. % vanadium (V) oxide, and approximately 5 wt. % to approximately 10 wt. % tungsten (VI) oxide is used to form the coating material 102.

[0253] It may be advantageous if one or more additives are admixed to the resulting mixture. Monoethanolamine and/or a colloidal silicon dioxide dispersion, for example, are suitable as one or more additives.

[0254] A proportion of the silicon dioxide dispersion is preferably approximately 2 wt. % or more and/or approximately 5 wt. % or less, based on a total mass of the mixture. A proportion of the silicon dioxide in the silicon dioxide dispersion is preferably 30 wt.%, based on a total mass of the silicon dioxide dispersion.

[0255] The mixture is preferably dried in a furnace and then calcined at approximately 400 C. to approximately 600 C.

[0256] In order to apply the coating material 102 to the shaped body 100, the coating material 102 is preferably dissolved and/or dispersed in a liquid. A quantity of the liquid preferably corresponds to a pore volume of the shaped body 100.

[0257] After application, the composite body 104 is preferably produced by firing.

[0258] The shaped body 100 and/or the composite body 104 are particularly suitable for use in exhaust gas aftertreatment, for example as catalytic converters and/or as diesel particle filters.