JPH0671184A - Metal carrier for catalyst for purifying vehicle exhaust gas - Google Patents

Abstract

PURPOSE:To obtain a catalyst carrier which is excellent in heat resistance and cyclic use resistance and fitted with an electric heating device by a method wherein an oxide having a specific melting point and a specific thickness is interposed between stainless foils as in the form of a flat plate or this stainless foil and a corrugated stainless foil and then baked to form an insulated layer in a honeycomb structure. CONSTITUTION:A honeycomb structure 3 having a stainless foil 7 as in the form of a flat plate and a corrugated stainless foil 8 laid one upon another is fitted into a cylinder 2 having positive and negative electrodes. In the metal carrier thus formed with an electric heating device provided therein to support thereon the catalyst for purifying vehicle exhaust gas, an oxide having a melting point of 800-1400 deg.C and a thickness of at most 1mm (e.g. the oxide Al2O3-SiO3 having Mn added thereto to adjust its melting point) is interposed between the stainless foils 7a or this stainless foil 7a and a corrugated stainless foil 8 in the honeycomb structure 3 to form the paired stainless foils and such stainless foils are disposed between the stainless foils 7 and 8 forming the honeycomb structure 3 and then baked to form an insulated layer 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying catalyst metal carrier for automobiles, and more particularly to an exhaust gas purifying catalyst metal carrier (hereinafter, simply referred to as a metal carrier) with an electric heating device having excellent heat resistance and heat cycle resistance. .

[0002]

2. Description of the Related Art It is well known that the above metal carrier is used as a device for purifying exhaust gas of an automobile. This metal carrier is generally formed by laminating a flat plate-shaped stainless foil and a corrugated stainless foil into a honeycomb structure, and loading the honeycomb structure inside a tubular body for conducting exhaust gas. Is.

FIG. 15 is a sectional structural view showing an example of the above-mentioned known metal carrier. In FIG. 15, reference numeral 21 denotes a tubular body for conducting exhaust gas, and a flat stainless steel foil 22 and a corrugated stainless steel foil (hereinafter,
A honeycomb structure 24 formed by stacking corrugated stainless steel foil 23 is spirally loaded to form a metal carrier 20. The flat plate-shaped stainless steel foil 22 and the corrugated stainless steel foil 23 are bonded by diffusion bonding or brazing to have a structure that can withstand high temperature and high speed exhaust gas and rapid heating and cooling. As the cylindrical body 21, not only the circular cross section of this example but also an elliptical shape as shown in FIG. 16 or a variety of shapes such as a rectangular shape (not shown) has been conventionally proposed.

The metal carrier 20 described above is shown in FIG.
As shown in FIG. 2, it is usual that both ends thereof are joined to the cone-shaped guiding cylinder body 25 by welding or the like, and a carrier 26 composed of the guiding cylinder body 25 and the metal carrier 20 is connected to the manifold 27 for use. Reference numeral 28 denotes an exhaust pipe for discharging the purified exhaust gas.

By the way, in the conventional general metal carrier, the metal carrier is not heated for about 30 seconds after the engine is started, and the temperature does not reach the temperature at which the catalyst functions sufficiently. Therefore, exhaust gas immediately after the engine is started cannot be sufficiently purified. There was a drawback. In order to overcome this drawback, it is effective to preheat the metal carrier and raise it to a temperature at which the catalyst works before starting the engine.
Technical means for wrapping a heater around the outer periphery of a metal carrier as disclosed in Japanese Patent Laid-Open No. 1-29362, or JP-A-2-22362
As disclosed in Japanese Patent Laid-Open No. 2 (1994), there has been conventionally proposed a technical means for forming an electrode on the above-mentioned honeycomb structure and heating it by energizing it.

However, the technical means of winding the heater around the outer circumference of the metal carrier has a drawback that it takes time to heat the inside because the heat generating portion is only the outer circumference. Further, in the technical means for forming electrodes in the honeycomb structure, since there is no means for forming an electric current path by providing an insulating layer, when the central part and the outer peripheral part of the honeycomb structure are energized, only the central part has a high current density. Therefore, it is difficult to uniformly heat the metal carrier. On the other hand, in the case of heating the outer peripheral portions, only the outer peripheral portions are heated, which again has a drawback that uniform heating cannot be performed.

In order to solve the above-mentioned drawbacks caused by the energizing means, it is disclosed in, for example, Japanese Patent Publication No. 3-500911.
In addition, as shown in FIG. 15, the insulating layer 29 is formed on the honeycomb structure 24 loaded in the tubular body 21 and the tubular body 2 is formed.
1 is also provided with electrodes 40a and 40b (in this example, 40a is an anode and 41b is a cathode) and insulating materials 41a and 41b, and a technical means for forming a current path having a resistance suitable for electric heating is also known. is there. As an insulating material for forming the insulating layer 29, Japanese Patent Laid-Open No. 3-500911 discloses a granular ceramic or a ceramic fiber mat. In FIG. 15, arrow x indicates the direction of current flow.

Although the exhaust gas purification efficiency immediately after the engine is started is improved by providing such a metal carrier, in addition to the heat cycle in which the engine is repeatedly operated and stopped, the high temperature exhaust gas prevents the metal carrier from being exhausted. Since it is used in a severe environment where it passes through the inside at high speed, the durability of the metal carrier itself is extremely low, which is a major obstacle to practical use.

In particular, as shown in FIG. 17, the metal carrier has a higher exhaust gas temperature at a position as close as possible to the exhaust manifold 27, which is advantageous from the viewpoint of the functionality of the catalyst. The heat resistance mentioned above,
Demand for heat cycle resistance becomes strict. Therefore, the insulating layer in the prior art using the above-mentioned granular ceramic, ceramic fiber mat or the like has a fatal defect that it is very vulnerable to thermal shock due to thermal cycle, and it is difficult to put it into practical use.

It is also possible to use an oxide such as alumina or silica as an insulating layer in place of the granular ceramic or the ceramic fiber mat, for example, as disclosed in JP-A-2-227135.
It is disclosed in Japanese Patent Publication No. However, the present inventors have confirmed in many experiments that simple coating of alumina or silica does not provide a drastic solution to the above-mentioned drawbacks.

That is, in the above-mentioned conventional means, even if the insulating layer is formed, since the insulating layer and the stainless steel foil forming the honeycomb structure are not completely joined to each other, heat cycle resistance cannot be obtained, so that the conventional method is practically used. It was not possible to secure the durability that it could endure.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a metal carrier in which a honeycomb structure in which the flat plate-shaped stainless steel foil and the corrugated stainless steel foil described above are laminated is loaded in a cylinder having both positive and negative poles. 80
Heat resistance to high temperature of 0 ° C or higher, heat cycle resistance to withstand severe thermal cycle of temperature difference of 800 ° C or higher between room temperature and high temperature of 800 ° C or higher, electricity of bonded part of bonded insulating material and honeycomb structure It is an object of the present invention to provide a metal carrier which simultaneously satisfies the three insulating properties.

[0013]

[MEANS FOR SOLVING THE PROBLEMS] In the metal carrier of the present invention for solving the above problems, a honeycomb structure in which a flat plate-shaped stainless foil and a corrugated stainless foil are laminated is loaded into a cylindrical body having both positive and negative electrodes. In the metal carrier, the melting point is between the flat plate-shaped stainless steel foil and the flat plate-shaped stainless steel foil adjacent to each other in the honeycomb structure, or between the flat plate-shaped stainless steel foil and the corrugated stainless steel foil, or between the corrugated stainless steel foils. A stainless steel foil pair is formed by interposing an oxide having a temperature of 800 ° C. or more and 1400 ° C. or less and a thickness of 1 mm or less, and the stainless steel foil pair is placed between the stainless steel foils constituting the honeycomb structure and then fired. Then, an insulating layer is formed.

Another feature is that the method of joining the stainless steel foil pair and the honeycomb structure with the oxide interposed in the metal carrier is performed by brazing.

Furthermore, the stainless steel foil forming the stainless steel foil pair in the metal carrier has been pre-oxidized, or the brazing filler metal foil and the stainless steel foil are used for brazing the stainless steel pair which has been further oxidized. Ti or Zr between the pair of stainless steels
It is characterized by the inclusion of the foil.

Another feature is that the stainless steel foil forming the stainless steel foil pair contains at least 1% of Al, and the stainless steel foil forming the stainless steel foil pair is at least 10% or more of Cr. , Al in an amount of 3% or more, or the stainless steel foil forming the stainless steel foil pair has at least Cr of 10% or more, Al of 3% or more, and a lanthanoid element of 0.
Another feature is that the content of O is 01 wt% or more.

[0017]

According to the present invention, in order to provide a metal carrier capable of withstanding the above-mentioned three characteristics, particularly the severe thermal cycle of engine start / stop, the insulating layer in the honeycomb structure is provided with the above-mentioned stainless foil pair. The melting point is 8 between the adjacent flat plate-shaped stainless foils and the flat plate-shaped stainless foils, or between the flat plate-shaped stainless foil and the corrugated stainless foils, or between the corrugated stainless foil and the corrugated stainless foils.
The main feature is that an oxide having a temperature of 00 ° C. or higher and 1400 ° C. or lower and a thickness of 1 mm or less is interposed and then baked to form.

That is, the optimum range of the melting point of the oxide to be interposed between the stainless steel foils, the optimum thickness, etc. are clarified,
Firmly join the opposing stainless steel foils across the oxide,
Moreover, by electrically and reliably insulating these two stainless steel foils, the electrical insulation required of the metal carrier,
It is possible to simultaneously satisfy the three characteristics of heat resistance and heat cycle resistance.

FIG. 1 is a perspective view for explaining the basic structure of a metal carrier according to the present invention, and FIG. 2 is FIG. 1A-A '.
FIG. 3 is a partially enlarged view of a portion A in FIG.

In the metal carrier 1 of this embodiment, a honeycomb structure 3 is spirally loaded in a tubular body 2 having a circular cross section. The cylindrical body 2 includes an anode terminal 4 and a cathode terminal 5,
The anode terminal 4 is connected to an electrode rod 4b arranged substantially at the center of the cylindrical body 2 via a conductor 4a. Reference numeral 6 denotes an insulator which electrically insulates the anode terminal 4, the conductor 4a and the like from the cylindrical body 2. The honeycomb structure 3 is formed by laminating a flat plate-shaped stainless steel foil 7 and a corrugated stainless steel foil 8.

Reference numeral 9 denotes an insulating layer. In this embodiment, an oxide layer 1 described later is provided between the adjacent flat plate-shaped stainless steel foils 7a and 7a.
It is formed by firing the oxide 10 with 0 interposed. The insulating layer 9 has a function of forming a current path in the honeycomb structure 3 loaded in the tubular body 2. The arrow y indicates the direction of current conduction in the current path. The flat plate-shaped stainless steel foils 7a and 7a facing each other with the oxide 10 interposed therebetween are referred to as a stainless steel foil pair in the present invention.

The stainless steel foil pair 11a is as shown in FIGS.
In the embodiment, the flat plate-shaped stainless steel foils 7a and 7a are used. However, as shown in FIG.
And a stainless steel foil pair 11c, 1 with an oxide 10 interposed between corrugated stainless steels 8a and 8a adjacent to each other as shown in FIGS. 5 and 6.
Even if 1d is configured, it is sufficiently possible to exhibit the function of the present invention described later.

The stainless steel foil pair 11 (hereinafter, the various stainless steel foil pairs are collectively referred to as the stainless steel foil pair 11) is appropriately spaced between the other stainless steel foils 7 and 8 constituting the honeycomb structure 3. Will be placed in. The honeycomb structure 3 and the stainless steel foil pair 11 arranged in the honeycomb structure 3 are generically referred to as a honeycomb core 30 hereinafter.

Next, the means for forming the honeycomb structure 3 and the stainless steel foil pair 11 will be specifically described. In the embodiment shown in FIGS. 1 and 2, the electrode rod 4b located in the central portion of the tubular body 2 serves as an anode, the terminal 5 located on the outer periphery of the tubular body 2 has a function as a cathode, and the terminals 4b to 5 are provided. By applying a voltage between them, a current flows through the honeycomb structure 3 in the direction indicated by the arrow y, and the metal carrier 1 is heated uniformly.

The honeycomb structure 3 and the stainless steel foil pair 11 can be efficiently formed by the following procedure. First, as shown in FIG. 7, one surface of a stainless steel foil (flat stainless steel foil 7a in this embodiment) is coated with the oxide 10 kneaded into a paste by kneading with an organic vehicle, and a coating layer of this oxide 10 is applied. A flat plate-shaped stainless steel foil 70 having

Next, as shown in FIG. 8, the ordinary flat plate-shaped stainless steel foil 7 and the corrugated stainless steel foil 8 which constitute the honeycomb structure 3 are sequentially laminated. The flat plate-shaped stainless steel foil 70 having the coating layer of the oxide 10 constitutes a stainless steel foil pair 11a by laminating in the opposite directions so that the oxides 10 contact each other, and the flat plate-shaped stainless steel foil 7 and the corrugated stainless steel foil are formed. 8 is placed in an appropriate portion and laminated.

It is preferable that foil-shaped brazing filler metal (hereinafter referred to as brazing filler metal foil) 12 is attached to the front and back surfaces of the flat plate-shaped stainless steel foil 7 in advance by an adhesive or spot welding. The flat plate-shaped stainless steel foil 7b is a flat plate-shaped stainless steel foil which is formed longer than the other flat plate-shaped stainless steel foils 7 by the circumferential length of the honeycomb core 30 for brazing the tubular body 2 and the honeycomb core 30.

On the other hand, a cross-shaped cut groove 4c is formed in the electrode rod 4b as shown in FIG. As shown in FIG. 8, the bundled stainless steel foils 7 and 8 and the stainless steel foil pair 11a which are laminated in the cut groove 4c to form the honeycomb core (the laminated stainless steel foils are generically referred to as stainless steel foils hereinafter). I will insert the end of
Fix it. FIG. 10 is a cross-sectional view showing a state in which two sets of the stainless steel foil bundles are respectively fitted and inserted into two facing cut grooves 4c. In order to efficiently insert the end portions of the bundle of stainless steel foils, it is effective to provide folds 7e, 8e and 70e at the end portions of the stainless steel foils as shown in FIG. is there. In addition, a flat plate-shaped stainless steel 7 for brazing the above-mentioned cylindrical body 2 and honeycomb core 30
b is loaded only on one side.

Then, the stainless steel foil bundle is wound around the electrode rod 4b as shown in FIG. By this winding, the honeycomb structure 3 is formed, and a layer of the spiral oxide 10 is formed inside the honeycomb structure 3 to form the honeycomb core 30. After that, in order to adjust the outer diameter of the honeycomb core 30 wound up, the end of each stainless steel foil is appropriately cut, and its length is adjusted.
As shown in FIG. After that, the conductor 4a, the anode terminal 4, and the cathode terminal 5 are connected to the electrode rod 4b, and the insulator 6 is attached to form the metal carrier 1.

In the above embodiment, the cut groove 4c of the electrode rod 4b.
Since two sets of the above-mentioned stainless steel foil bundles are respectively inserted in the above, two series of layers of the spiral oxide 10 having the electrode rod 4b as a base point are formed as shown in FIG. On the other hand, when the stainless steel foil bundle is inserted only in the cut groove 4c on one side, the result shown in FIG.
A series of layers of helical oxide 10 can be formed as shown in FIG.

The metal carrier 1 formed by the above-mentioned means,
For example, it is heated in a vacuum atmosphere at 1200 ° C. and baked. By this firing, the brazing filler metal foil 12 is melted, the flat plate-shaped stainless steel foil 7a and the corrugated stainless steel foil 8b are joined, and the oxide 10 is also melted in the stainless steel foil pair 11a, which reacts with the stainless steel foil 7a to form a flat plate shape. The stainless steel foils 7a are firmly joined to each other, and the fired oxide insulating layer 9 is formed between the flat plate-shaped stainless steel foils 7a.

As described above, the oxide 10 interposed between the pair of stainless steel foils 11 is fired to form the insulating layer 9, and the stainless steel foils which are opposed to each other with the oxide 10 sandwiched therebetween are solidified. Demonstrate the function of joining.

In the metal carrier 1, exhaust gas passes through the honeycomb core 30 at high speed during engine operation. Therefore, when the bonding strength between the insulating layer 9 and the stainless steel foil is low, the honeycomb core 30 is gasified by the gas flow. Phenomenon of shifting in the flow direction occurs. If this deviation is large, it becomes impossible to energize due to the cutting of the stainless steel foil forming the honeycomb core 30,
Alternatively, it becomes impossible to uniformly heat the metal carrier 1 due to insulation failure due to breakage of the joint between the insulating layer 9 and the stainless steel foil.

The use environment targeted by the present invention is about 80.
Since the environment is a high temperature of 0 ° C. or higher, an oxide having a low melting point, for example, an oxide such as a low melting glass containing a large amount of lead cannot be used. As a result of many experimental studies, the present inventors have found that the use of an oxide having a melting point of 800 ° C. or higher does not increase the deviation of the honeycomb core 30 and can provide heat resistance.

Further, as described above, a thermal cycle occurs with the operation / stop of the engine. If the insulating layer 9 is destroyed by the thermal cycle, the honeycomb core 30 is displaced. First, in order to obtain the heat cycle resistance of the insulating layer 9,
The oxide itself needs to be thin. The upper limit value is 1 mm. Further, in order to withstand the heat cycle between room temperature and 800 ° C, the melting point of the oxide needs to be 1400 ° C or less.

When the thickness of the oxide exceeds 1 mm, it is easy for the oxide to break due to the difference in thermal expansion between the oxide and the stainless steel foil. When the melting point of the oxide is 1400 ° C. or lower, the oxide can be deformed at a relatively low temperature, so that it is possible to absorb thermal shock. However, when the melting point exceeds 1400 ° C., the deformability of the oxide is reduced. Since it is insufficient, the insulating layer 9 is destroyed by the heat cycle, and the displacement amount of the honeycomb core 30 increases.

As an example of the oxide satisfying the above characteristics, A
l ₂ O ₃ -SiO ₂ system, MgO-SiO3 series, Al ₂ O
₃ -MgO system, Al ₂ O ₃ -CaO based, CaO-SiO
_{2 system, Al 2 O 3 -CaO-SiO} 2 system, SrO-Al
₂ O ₃ —SiO ₂ system, MgO—Al ₂ O ₃ —SiO
₂ system, and based on the BaO-Al ₂ O ₃ oxide -SiO ₂ system, etc., it can be mentioned those added for melting adjust the oxides such as B ₂ O ₃ and MnO. However, other materials can be used as long as they satisfy the melting point range of 800 to 1400 ° C.

In order to enhance the bonding effect between the oxide 10 and the stainless steel foil, it is effective to pre-oxidize the stainless steel foil forming the stainless steel foil pair 11. When such an oxidation treatment is performed, the wettability between the oxidized stainless steel foil and the brazing material may be deteriorated. In order to solve this, it is an effective means to interpose a Ti or Zr foil 13 on the surface of the brazing filler metal foil 12 in contact with the oxidized stainless steel foil 70 as shown in FIG.

Further, it is effective to improve the heat resistance cycle resistance of the metal carrier that the surface of the stainless steel forming the stainless steel foil pair is made uneven.

As the stainless steel used in the present invention, particularly in the stainless steel foil forming the stainless steel foil pair, if 1% by weight or more of Al is contained, a dense alumina film is formed on the surface. Oxides of iron and nickel have poor adhesion to the metal substrate because the oxide formation site is the interface between the oxide and the gas phase, and therefore the film grows to the outside. Since it is an oxide film that grows toward the inside, the adhesion of the stainless steel foil itself to the metal substrate is very good. Therefore, the bonding strength between the oxide forming the insulating layer and the stainless steel foil is improved, which is advantageous in reducing the deviation amount of the honeycomb core.

Furthermore, the stainless steel foil forming the stainless steel foil pair contains at least 10% of Cr and 3% of Al.
% Or more, the adhesion of the oxide film on the surface of the stainless steel foil exhibits an extremely excellent function as compared with the case where Cr is not contained. Further, if the lanthanoid element is contained in an amount of 0.01% by weight or more in addition to the above Cr and Al, the oxide film becomes thick only in the portion where the lanthanoid element is segregated, and as a result, the shape of the oxide film is Since a wedge is punched in, the oxide film exhibits a further excellent effect in that the adhesion of the oxide film is further improved.

The metal carrier of the present invention is not limited to the above-mentioned embodiment, but can be applied to a metal carrier 1a having a square cross section as shown in FIG. 13, for example. The embodiment of FIG. 13 shows a plan view in which the honeycomb structure 3a is loaded into the rectangular cylindrical body 2a to form the metal carrier 1a. The cylindrical electrode 2 has an anode electrode 4 and a cathode electrode 5
Is directly attached to the anode electrode 4 and the cathode electrode 5
Insulators 14 and 14a are provided to prevent current from flowing through the cylindrical body 2a when a voltage is applied to the cylinder.

The insulating layer 9a of the present invention comprises a pair of stainless steel foils (in this embodiment, flat stainless steel foils) at appropriate intervals in the honeycomb structure 3a formed by laminating the flat stainless steel foil 7 and the corrugated stainless steel foil 8. (Apply the one formed by interposing the oxide 10 between the corrugated stainless steel foil 8a and 7a)
11b is arranged and is fired in the same manner as described above.

Thus, in the metal carrier 1a of this embodiment, the cathode terminal 5 is formed from the cylindrical upper plate 2a1 connected to the anode terminal 4 via the honeycomb structure 3a divided by the insulating layer 9a.
An electric current flows through the cylindrical lower plate 2a2 connected to the metal carrier 1a to heat the metal carrier 1a.

FIG. 14 shows an embodiment of a rectangular metal carrier 1b similar to that shown in FIG. 13, in which the cylindrical body 2b is made of, for example, an insulating ceramic plate. Is the flat stainless steel foil 7 as in FIG.
The honeycomb structure 3b formed by laminating the corrugated stainless steel foil 8 is loaded. The insulating layer 9b is the insulating layer 9b.
The ends of the honeycomb structures 3b divided by are opened so as to alternately contact with each other. Such an insulating layer 9b is a pair of stainless steel foils (two flat stainless steel foils 7 in this embodiment).
It is possible to form easily by adjusting the length of 11a and arranging it in the honeycomb structure 3b.
The anode terminal 4 and the cathode terminal 5 are the same as the honeycomb structure 3
It is electrically connected to b.

[0046]

【Example】

[Embodiment 1] By the forming means shown in FIGS.
The metal carrier 1 shown in FIG. 2 was manufactured, an actual engine test was performed on the manufactured metal carrier 1, and the deviation amount of the honeycomb core 30 in the exhaust gas flow direction was investigated.

The stainless steel foil forming the stainless steel foil pair 11 is a flat stainless steel foil 7a having a thickness of 50 μm and a width of 17 mm and corresponding to SUS430.
A was subjected to an oxidation treatment in the atmosphere at 1100 ° C. for 60 minutes to form an oxide film on the surface. This flat stainless steel foil 7a
As shown in FIG. 7, paste-form oxides having various melting points were applied in various thicknesses.

As the oxide 10, an Al ₂ O ₃ —SiO ₂ type oxide having a melting point adjusted by adding boron, manganese, calcium, magnesium or the like was used. In this embodiment, a powder having an average particle size of 10 μm, the melting point of which is adjusted to 700 to 1500 ° C., is kneaded with an organic vehicle to form a paste, and the thickness thereof is adjusted by a spray printing method. Applied.

Further, the flat plate-shaped stainless foil 7 and the corrugated stainless foil 8 constituting the honeycomb structure 3 have a thickness of 50.
A stainless foil (length about 500 mm) corresponding to SUS430 having a width of 17 μm and a width of 17 mm was prepared and laminated as shown in FIG.
15 mm of Ni-based brazing filler metal foil (BNi-5) 12 having a thickness of 25 μm is provided on the front and back surfaces of the flat stainless steel foil 7.
I stuck them at intervals. The brazing material foil 12 which is coated with the oxide 10 and is arranged so that the surfaces coated with the oxide are in contact with each other and is in contact with the stainless steel foil 70 on which the stainless steel foil pair 11 is formed,
Similar to the above, Ni-based brazing material foil with a thickness of 10 × 10 mm and a thickness of 25 μm was adhered at intervals of 40 mm.
A Ti foil 13 having a thickness of 10 mm and a thickness of 5 μm was attached. One end of all the stainless steel foils is bent upward by 3 mm at a right angle to form folds 7e, 8e, 70e.

The stacked stainless steel foil bundles were formed on the honeycomb core 30 in the same manner as shown in FIGS. 9 to 11 and loaded into the cylindrical body 2 to manufacture the metal carrier 1. The electrode rod 4b
Is composed of a Ni rod having a diameter of 8 mm and a length of 50 mm, and a cross-shaped cut groove 4c having a width of 1 mm and a length of 17 mm is formed at one end of the electrode rod 4b.

The metal carrier 1 manufactured as described above
Was baked in a vacuum at a temperature of 1200 ° C. for 10 minutes, and then the conductor 4a, the anode terminal 4, the cathode terminal 5, and the insulator 6 were attached to finish the metal carrier 1 as a final product.

The metal carrier 1 was attached to a test apparatus similar to that shown in FIG. 17, and the amount of core misalignment after thermal cycle loading was investigated. In order to attach to the test apparatus, guide cylinders 25 were fixed to both ends of the metal carrier 1 by welding.

The test condition is a temperature pattern in which the metal carrier 1 is heated to 850 ° C. in 10 minutes after the engine is operated, and then the engine is stopped and cooled to 100 ° C. in 14 minutes. Gas flow rate is about 8 per second
It is 0 liter.

The evaluation of the heat cycle resistance was conducted by using the honeycomb core 30.
The amount of displacement from the original position (deviation amount) was evaluated. Table 1 shows an example of this investigation result, which is an investigation of the deviation amount after applying the thermal cycle load 900 times, and the deviation amount of 1 mm or less is passed (○) and exceeds 1 mm. Those that are rejected are shown as rejects (x).

As a comparative example, the results of carrying out the same test by producing a metal carrier using a commercially available inorganic adhesive instead of the oxide are also shown.

[0056]

[Table 1]

As is clear from Table 1, in the case of using the inorganic adhesive (melting point 1600 ° C.) or the oxide having a melting point 1500 ° C., the core was largely displaced after 900 cycles. On the other hand, it was confirmed that the metal carriers of the present invention all had a deviation amount of 1 mm or less, and could withstand practical use.

Further, in the metal carrier of the present invention, the temperature raising performance by energization is 400 ° C. when 2.5 kW of electric power is used.
It took 7 seconds to reach, and it was confirmed that this point is also sufficient for practical use.

[Embodiment 2] In Embodiment 1, the stainless foil forming the stainless steel foil pair 11 is made of Fe-10Cr-.
The aluminum foil was changed to 3 Al, and the stainless steel foil was subjected to mechanical asperity processing by sandblasting, anodic oxidation in sulfuric acid, or yttrium ion implantation, and after the treatment, an intervening oxide paste was directly applied, or 1100 After pre-oxidizing for 60 minutes at ℃,
The oxide carrier 10 was applied, and otherwise the metal carrier 1 was manufactured in the same manner as in Example 1 and the above test was carried out. The thickness of the oxide 10 was fixed at 40 μm. Table 2 shows an example of the survey results.

From the results shown in Table 2, as in Table 1, those using the oxides having a melting point within the range of the present invention remained within 1 mm even if deviation occurred, and those pre-oxidized showed that. It turns out that it is superior to the one that is not done.

[0061]

[Table 2]

[0062]

As described above, the metal carrier of the present invention has a high heat cycle resistance against the heat cycle of engine shutdown, which has been impossible in the past, and at the same time has a heat resistance. Moreover, a metal carrier capable of uniform heating was obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a basic structure of a metal carrier according to the present invention.

FIG. 2 is a cross-sectional structural view taken along the line AA ′ of FIG.

FIG. 3 is an enlarged view of part A of FIG.

FIG. 4 is a partial cross-sectional view showing another example of an insulating layer according to the present invention.

FIG. 5 is a partial cross-sectional view showing another example of an insulating layer according to the present invention.

FIG. 6 is a partial cross-sectional view showing still another example of an insulating layer according to the present invention.

FIG. 7 is a cross-sectional view showing a state in which an oxide is applied to the surface of a flat stainless steel foil.

FIG. 8 is a schematic view showing a laminated state of flat plate-shaped stainless foil, corrugated stainless steel foil, and a pair of stainless steel foils.

FIG. 9 is a perspective view showing an example of an electrode rod.

FIG. 10 is a schematic diagram showing a state where a stainless steel foil bundle is attached to an electrode rod.

FIG. 11 is a schematic diagram showing a state in which a stainless steel foil bundle is wound around an electrode rod.

FIG. 12 is a cross-sectional structural view showing the basic structure of a metal carrier having one series of insulating layers.

FIG. 13 is a sectional structural view showing another example of the metal carrier according to the present invention.

FIG. 14 is a sectional structural view showing another example of the metal carrier according to the present invention.

FIG. 15 is a sectional view showing an example of a conventional metal carrier.

FIG. 16 is a sectional view showing another example of a conventional metal carrier.

FIG. 17 is a schematic view showing an example of a usage state of a metal carrier.

[Explanation of symbols]

1, 1a, 1b Metal carrier 2, 2a, 2b Cylindrical body 3, 3a, 3b Honeycomb structure 30 Honeycomb core 4 Anode terminal 4a Conductor 4b Electrode rod 4c Cut groove 5 Cathode terminal 6 Insulator 7, 7a, 7b, 70 Flat plate-shaped stainless steel foil 7e Folded 8,8a Corrugated stainless steel foil 8e Folded 9,9a, 9b Insulating layer 10 Oxide 11, 11a, 11b, 11c, 11d Stainless steel foil pair 12 Brazing material foil 13 Ti or Zr foil 14 , 14a Insulator 20 Metal carrier 21 Cylindrical body 22 Flat stainless steel foil 23 Corrugated stainless steel foil 24 Honeycomb structure 25 Conducting cylinder body 26 Carrier 27 Manifold 28 Exhaust pipe 29 Insulating layer 40a Anode terminal 40b Cathode terminal 41a, 40b Insulator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C04B 37/02 Z C22C 38/00 302 Z

Claims (7)

[Claims] 1. An exhaust gas purifying catalyst metal carrier for automobiles with an electric heating device, comprising a honeycomb structure in which a flat plate stainless foil and a corrugated stainless foil are laminated in a cylindrical body having both positive and negative electrodes. In the above honeycomb structure, oxidation of a melting point of 800 ° C. or more and 1400 ° C. or less and a thickness of 1 mm or less is performed between adjacent flat plate-shaped stainless steel foils, or between flat plate-shaped stainless steel foils and corrugated stainless steel foils, or between corrugated stainless steel foils. A pair of stainless foils are formed by interposing an object, and the pair of stainless foils are arranged between the stainless foils constituting the honeycomb structure and then fired to form an insulating layer. Metal carrier for automobile exhaust gas purification catalyst. 2. The metal carrier for an automobile exhaust gas purification catalyst according to claim 1, wherein the joining of the stainless steel foil pair and the honeycomb structure is performed by brazing. 3. The stainless steel foil forming the stainless steel foil pair is previously oxidized.
Alternatively, the metal carrier for an automobile exhaust gas purification catalyst according to any one of 2). 4. The stainless steel foil pair and the honeycomb structure are joined by brazing, and a Ti or Zr foil is interposed between the brazing material foil and the stainless steel forming the stainless steel foil pair. 3. A metal carrier for an automobile exhaust gas purification catalyst according to 3. 5. The metal for automobile exhaust gas purification catalyst according to claim 1, wherein the stainless steel foil forming the stainless steel foil pair contains at least 1% of Al. Carrier. 6. The stainless steel foil constituting the stainless steel foil pair contains at least 10% of Cr and 3% of Al, and the stainless steel foil of claim 1, 2, 3 or 4.
A metal carrier for an automobile exhaust gas purification catalyst according to any one of 1. 7. The stainless steel foil forming the stainless steel foil pair contains at least Cr 10% or more, Al 3% or more, and lanthanoid element 0.01% by weight or more, 1, 2, 3 or The metal carrier for an automobile exhaust gas purification catalyst according to any one of 4 above.