EP2219861A2

EP2219861A2 - Functional composite material

Info

Publication number: EP2219861A2
Application number: EP08852078A
Authority: EP
Inventors: Walter Mittelbach; Ralph Herrmann; Jürgen Bauer
Original assignee: Sortech AG
Current assignee: Sortech AG
Priority date: 2007-11-23
Filing date: 2008-11-19
Publication date: 2010-08-25
Also published as: CN101909872A; WO2009065852A2; CN101909872B; EP2671717B1; US20110027506A1; WO2009065852A3; EP2671717A1; JP5364720B2; KR20100102109A; KR101467613B1; JP2011509192A; BRPI0819793B1; BRPI0819793A2; US9259909B2; ES2645404T3; DE102007056587A1

Abstract

The invention relates to a functional composite material consisting of a support (1) and a functional surface material (2). The composite material is characterised in that the support has a structured boundary layer (3) with a lower boundary (4), an upper boundary (5) a cross-linking depth (d) between the lower and upper boundaries and a substance boundary (6) that alternates between the upper and lower boundaries on the surface facing the functional surface material. The substance boundary (6) is designed in particular as a continuous sequence of surface moulded sections (7) of the support with spaces (8) therebetween, each moulded section having a height (h) that equals the cross-linking depth and at least one moulded section and at least one space (8) lie within a horizontal width (b) corresponding to a multiple of the cross-linking depth.

Description

Functional composite material

description

The invention relates to a functional composite material consisting of a carrier and a functional surface material, according to the preamble of claim 1.

Functional composite materials have a broad technical field of application. Such materials are particularly important in sorption and catalytic processes with significant heat of reaction of crucial importance. Furthermore, they are used in the field of corrosion and antifouling protection in order to make the surfaces of chemical and technical apparatus insensitive to the influences of aggressive chemical substances or to avoid deposits.

Functional composite materials consist of a carrier material, for. Example, metallic materials, ceramics or glass materials u nd arranged on the surface of a functional material that serves as a catalyst, adsorbent, corrosion or Antifoulingschutz, insulator or electrical functional layer.

In the conventional production processes, the functional materials are applied as shaped articles, in particular pellets, or as coatings to the corresponding support material. In most cases, the surface of the carrier material is not completely covered or coated with the functional material. The result is an insufficient mechanical connection of the functional materials to the carrier surface and insufficient thermal contact between the carrier material and the coating.

Coating methods which lead to a comparatively firm, direct and surface contact between carrier material and functional material in which the carrier surface is completely covered are, for example, an in-situ crystallization, a recrystallization or a consuming crystallization. The resulting mechanical properties of the Although composite material and the achieved thermal coupling between the two components is in the end better, but by no means optimal for many conditions of use.

Thus, for example, due to the different thermal expansion of the carrier material and the coating with rapid temperature changes, there are always problems of strength in connection with a detachment of the functional coating. Such problems occur especially in Temperierungsprozessen, calcinations and adsorbent activations. In addition, as the coating thickness of the functional material increases, the heat transfer in the composite is severely limited.

From the aforementioned problems, the object underlying the invention to provide a functional composite material with which the mentioned disadvantages and functional impairments can be avoided sustainably results. The required composite material should have a high thermal capacity, the mechanical bond between the substrate and functional coating should be able to withstand high loads even with higher layer thicknesses and the heat transfer in the composite should have technically optimal values. The required composite material should be versatile applicable. Process steps for producing such a composite material are to be specified.

The object is achieved with a functional composite material consisting of a carrier and a functional surface material having the features of claim 1. With regard to the method aspect, the object is achieved with a method for producing a composite material having the features of claim 16. The respective subclaims indicate expedient or advantageous embodiments of the composite material or of the production method used therefor.

According to the invention, the material boundary between the carrier and the functional surface material is not flat. The material boundary is rather structured within a boundary layer. This boundary layer has a thickness called the crosslinking depth. It is in the direction of the functional surface material limited by an upper limit and in the direction of the carrier of a lower limit. As a result, the carrier is interlocked on its corresponding surface with the functional surface material. This requires a greatly increased connection of the functional surface material on the surface of the carrier with intensive thermal contact between the two components. The thermal contact resistance between the carrier and surface material is thereby minimized.

In particular, the fabric border is formed as a continuous sequence of superficial formations of the carrier with gaps, each formation having a height equal to the depth of crosslinking. In addition, at least one formation and at least one intermediate space are arranged within a horizontal width of the boundary layer corresponding to a multiple of the crosslinking depth.

This requires optimum coordination between the height of the formations and thus the thickness of the boundary layer or its crosslinking depth and the width of the formations, which are necessary for optimum mechanical strength and good thermal contact in the composite.

Expediently, the formations have a first mold width in the region of the lower boundary and a second mold width different from the first mold width in the region of the upper boundary of the structured boundary layer. The thus achievable contour of the formations can improve the thermal contact between the carrier and the coating or contributes to the improved strength of the composite structure.

In an advantageous embodiment, the resulting material boundary runs repeatedly along the lower limit and the upper limit of the structured boundary layer on a horizontal width corresponding to at least twice the crosslinking depth. Such a relationship between width and height of the formations proves to be particularly favorable in thermal, chemical and mechanical terms. The length of the alternating material boundary is expediently such that it amounts to at least 1.1 times, preferably 1.3 to 2.5 times, a length of a flat material boundary of the carrier. The associated correspondingly enlarged contact area between carrier and functional surface material has proven to be thermally advantageous. The crosslinking depth has a value in the range from 5 to 100 .mu.m, in particular from 5 to 60 .mu.m.

The Ausformu lengths may be formed in different shapes. In a first variant, the formations form a series of webs with a rectangular, dovetailed and / or wavy contour. The rectangular and wavy contour is advantageous in view of the thermal contact between the surface material and the carrier and with respect to a simpler production, the dovetail-like contour imposes a very strong mechanical bond in the composite structure.

The Ausformu lengths can also be formed as a series of knobs with a bell-shaped, inverted or upright truncated pyramidal and / or mushroom-shaped contour. In contrast to the webs which extend predominantly in a longitudinal direction, the knobs form a mountain-and-valley structure without preferential direction.

The carrier can be made of different materials. It may consist of a metallic material, a ceramic material or a glass material. It may be in the form of a sheet or a plate, a tube or a sponge. For the surface material also ls different materials come into consideration. The surface material may be an adsorbent, a catalytically active material or a corrosion and / or fouling protection, an insulator or an electrically functional material.

The composite material described above can be prepared in various ways. In a first embodiment, a method for applying, depositing and / or growing a surface structure is used to produce the formations. On an initially in the we- significant plane, that is, in the sense of the below-described evaluation unstructured surface of the carrier material is thus stored.

For this purpose, in situ crystallizations can be generated on the support, the formations can also be crystallized on the support.

Producing the formations is also possible by chemical or physical deposition of material from a gas phase. As an alternative to the aforementioned constituent surface treatments, it is also possible to use a material-removing, in particular material-dissolving, method for working out the formations from the surface of the carrier.

The composite material according to the invention will be explained in more detail below with reference to exemplary embodiments. The same reference numbers are used for identical or identically acting parts. For clarity, the attached figures serve 1 to 5. It shows

1 shows an exemplary first embodiment with a sequence of

Formations in a right-angled contour,

1a a support surface in an exemplary plan view,

Fig. 2 modified embodiments of the formations of Fig. 1 as

Trapezoidal or dovetail shape,

3 shows formations with a wave contour,

4 shows formations with a mushroom contour,

Fig. 5 forms in the form of bell-shaped knobs.

Fig. 1 shows a carrier 1 with a superposed functional surface material 2 which completely covers the carrier. The surface layer facing surface of the carrier has a series of formations 7 with intermediate spaces 8 between the formations. The totality The formations and spaces form a structured boundary layer 3 with a crosslinking depth d. The crosslinking depth denotes the distance between a lower boundary 4 and an upper boundary 5 of the structured boundary layer. It corresponds to the distance between the highest and the lowest level of the formations.

The height h of each individual formation corresponds substantially to the depth of crosslinking d of the structured boundary layer 3. The surfaces of the formations and the interspaces between them form the resulting material boundary 6 between the support and the surface material 2 at which the surface material and the material of the support in to be in direct contact. As can be seen from Fig. 1, the material boundary 6 alternates between the upper and lower limits 5 and 4 of the boundary layer 3. Its course is determined by the shape of the formations 7 and their Zwischenräu men 8. In comparison to a Stoffg renze 9 a flat support surface, it has an increased length. Integration-promoting material is not provided and is not necessary.

The sequence of the formations 7 and their spaces 8 is determined laterally with respect to the size of a horizontal width b. The horizontal width is expediently related to the crosslinking depth d of the structured boundary layer. It forms a lateral scale for the surface structure of the carrier. In the embodiment shown in Fig. 1, the horizontal width b is approximately twice the crosslinking depth d, wherein at least one formation 7 and a Zwischenrau m 8 are within this scale. The horizontal width b does not form a lattice constant in the narrower sense. The width of the formations and their spaces may vary individually. Rather, what is important is the number of formations within the scaling given by the horizontal width b or the ratio of b to the crosslinking depth d.

As shown in FIG. As shown in plan view, the formations may be formed in a completely irregular shape in a lateral direction, so that the sizes defined in FIGS. 1 and 2 are used to characterize the formations vary in width by an average. The crosslinking depth is essentially the same in the majority of the support surface.

As shown in FIG. 2 and the following figures, the formations may have a different contour from the rectangular shape. In such a case, a distinction is made between a first shape-wide sl in the area of the foot of the formation at the lower boundary 4 and a second shape width s2 in the area of the upper boundary 5 of the structured boundary layer. In a in Fig. 2 trapezoidal shape shown widened in the image on the left is the first mold width sl greater than the second mold width s2. In a in Fig. 2 shown dovetail-shaped shaping on the right is the second mold width s2 g rößer than the first mold width Si. The values of the shape widths and also their size ratio can vary within certain limits due to the formations on a carrier surface. The forms do not necessarily form a regular grid.

Fig. Figure 3 shows formations 7 and spaces 8 in a waveform. The material boundary 6 alternates continuously between the lower boundary 4 and the upper boundary 5 of the structured boundary layer 3. The first shape width sl corresponds to the horizontal distances between the deepest points within the spaces 8, the second, located near the upper boundary 5 Shape width is ideally arbitrarily small in this embodiment. In practice, however, the peaks of the wavy course of the material boundary in the region of the surface layer have a certain flattening, the second shape width s2 thus has a small but finite value.

Fig. 4 shows formations 7 with a mushroom-like shape. A wider in the region of the lower border 4 form in the area between the boundaries 4 and 5 in a tapered middle part and widens in the upper limit 5 again. The mushroom top structure may be described as a rounded embodiment of the dovetail structure of FIG. 2 are understood.

In the embodiments shown in FIGS. 3 and 4, the formations 7 extend over a portion of the surface of the support in a web-like manner. gers so that their cross sections are extruded over the surface of the carrier.

Fig. FIG. 5 shows a nub structure arranged on the support surface, consisting of a not necessarily uniform array of bell-shaped nubs 11 and intervening valleys which is covered by the surface coating 2. The nubs may also be in trapezoidal or dovetail form.

The structured interfaces, the progress of the material boundaries and their previously explained parameters can be detected and investigated in a very simple manner by microscopic methods. These are expediently combined with digital image processing. From the material boundary, which can be recognized on average as a one-dimensional line, the two-dimensional contact surface between the support and the surface coating can be concluded on the assumption of sufficiently isotropic structuring.

For this purpose, preferably embedded cross-sections are prepared from the composite samples to be examined, of which digital microscopic images are created. The magnification is expediently chosen so that the image section to be analyzed comprises at least 6, but better 10, formations. The viewing scale is appropriately set to set an appropriate ratio between image pixel and mesh depth. Using conventional image processing software, in particular a vector-based drawing program, the previously described quantities, i. H. the depth of crosslinking, the width of the formations and the length of the resulting material boundary, very easily determine.

To assess the resulting surface structure and depth of crosslinking, the starting point is the section of the functional composite material. Of these, an approximately 1 millimeter long section is transferred at a magnification of 100x to an image format of, for example, 1024x768 pixels. If the resulting surface structure is anisotropic, it is recommended to make the cuts at different angles with a corresponding subsequent evaluation of the resulting images. Crosslinking depths in the range of 15 to 60 μm have proven to be particularly expedient. However, crosslinking depths from 5 pm up to 100 pm are readily achievable and likewise show good properties when using the composite. In cross-section, the length of the resulting material boundary 6 can be determined and compared with the length of the material boundary in the case of an unstructured surface of the carrier.

Experiments have shown that the formations, in particular their width, their height or the resulting crosslinking depth are selected particularly expediently when the resulting material limit is increased by a factor of at least 1.4 relative to the material boundary of a flat, unstructured carrier surface.

The illustrated embodiments of the composite material have a significantly improved mechanical strength even under thermal stress. Particularly in the case of functional surface layers with brittle material properties, the risk of the coatings peeling off under thermal and mechanical loads is markedly reduced. The increased material limit as a result of the formations increases the heat transfer between the support and the functional surface layer and thus enables thicker coatings with the same efficiency in applications which have a strong evolution of heat. This is especially the case with catalytic and adsorption processes.

For producing a surface of the carrier in one of the mentioned embodiments, use is made in particular of consumptive crystallization when zeolites are used. In this case, a controlled carrier dissolution with controlled zeolite growth takes place. This results in a mountain and valley structure with dovetail-shaped knobs according to the embodiment of FIG. 5th

Similar surface structures can be realized by physical or chemical deposition methods, for example thermal evaporation, electron beam evaporation, laser beam or arc vaporization. Likewise, molecular beam epitaxy methods, Sputtering or ion plating can be used with or without the use of masks.

A zeolite layer having the mentioned properties can be produced in a wet chemical process, for example, by reacting a reaction solution comprising one part of phosphoric acid (H3PO4), 0.38 part of silicon dioxide (SiO.sub.2) in the form of silica sol, 3 parts of morpholine and 70 parts of water Aluminum or an aluminum alloy in an amount such that the ratio of the surface area of the carrier material measured in square centimeters to the volume of the solution indicated in milliliters is about 2 to 5. The thus prepared mixture is heated in a pressure vessel for 96 hours at a temperature of 175 ⁰ C and subsequently washed in water. As a result of the treatment, a SAPO-34 zeolite layer is formed on the surface of the carrier.

The composite material according to the invention was illustrated by means of exemplary embodiments. In the context of expert action changes can be made to the examples shown, which correspond to the inventive idea. Further embodiments emerge from the subclaims.

LIST OF REFERENCE NUMBERS

1 carrier

2 Functional surface material

3 boundary layer

4 lower limit

5 upper limit

6 material limit

7 shaping

8 space

9 Material border of a planar carrier surface

10 footbridge

11 pimples

Claims

claims

A functional composite material comprising a support (1) and a functional surface material (2), characterized in that the support has a structured boundary layer (3) with a lower limit (4) and an upper limit (5) with a crosslinking depth (i.e. ) between the lower and upper limits and an edge of material (6) alternating between the lower and upper limits on the surface facing the functional surface material.

A functional composite material according to claim 1, characterized in that the fabric border (6) is formed as a continuous series of superficial formations (7) of the carrier with gaps (8), each formation having a height (h) equal to the depth of crosslinking and within a horizontal width (b) of the boundary layer corresponding to a multiple of the crosslinking depth is at least one formation and at least one intermediate space (8).

3. Functional composite material according to claim 1 or 2, characterized in that the formations (7) have a first shape width (sl) in the region of the lower limit (4) and a second shape width different from the first shape width (s2) in the region of the upper limit ( 4) of the structured boundary layer (3).

4. Functional composite material according to one of claims 1 to 3, characterized in that the resulting material boundary (6) on a at least twice the crosslinking depth (2d) corresponding horizontal width (b) repeatedly at the lower limit (4) and at the upper limit ( 5) of the structured boundary layer (3).

5. Functional composite material according to one of claims 1 to 4, characterized in that a length of the alternating material boundary (6) is at least 1.1 times, preferably 1.3 to 2.5 times, a length of a flat material boundary (9) of the carrier (1).

6. The functional composite material according to claim 1, wherein the crosslinking depth (d) has a value of from 5 to 100 .mu.m, in particular from 5 to 60 .mu.m.

7. Functional composite material according to one of claims 1 to 6, characterized in that the formations are formed as an isotropic pattern (10) with a rectangular, trapezoidal, dovetailed and / or wavy contour.

8. Functional composite material according to one of claims 1 to 7, characterized in that the formations are formed as an array of nubs (11) with a bell-shaped, inverted or upright truncated pyramidal and / or pi lz head-like contour.

9. Functional composite material according to one of the preceding claims, characterized in that the carrier (1) is a metallic material.

10. The functional composite material according to claim 1, wherein the carrier is a ceramic material.

11. Functional composite material according to one of claims 1 to 8, characterized in that the carrier (1) is a glass material.

12. The functional composite material according to claim 9, wherein the carrier is a tube, sponge or sheet or has the shape of a plate.

13. A functional composite material according to any one of claims 1 to 12, wherein a surface material (2) is an adsorbent.

14. A functional composite material according to any one of claims 1 to 12, wherein a surface material (2) is a catalytically active material, an insulator or an electrically active material.

15. Functional composite material according to one of claims 1 to 12, characterized in that the surface material (2) is a corrosion and / or antifouling protection.

16. A method for producing a functional composite material according to one of the preceding claims, characterized in that for producing the formations, a method for applying, depositing and / or growing a surface structure is used.

17. The method according to claim 16, wherein the formations are produced by in-situ crystallization on the carrier.

18. The method according to claim 16, characterized in that the formations are crystallized on the support.

19. A method according to claim 16, wherein the formations are produced by a chemical or physical deposition from a gas phase.

20. A method for producing a functional composite material according to one of claims 1 to 15, in which a material-removing, in particular a material-dissolving, method for working out the formations from the surface of the carrier is used to produce the formations.

21. Method according to claim 20, characterized in that the formations are produced by an etching process.