JP3268817B2 - Metal carrier for automobile exhaust gas purification catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art It is well known that the above-described metal carrier is used as a device for purifying exhaust gas of automobiles. This metal carrier is generally formed by laminating a flat stainless steel foil and a corrugated stainless steel foil to form a honeycomb structure, and loading the honeycomb structure inside a cylindrical body for conducting exhaust gas. It is.

FIG. 15 is a sectional view showing an example of the above-mentioned known metal carrier. In FIG. 15, reference numeral 21 denotes a cylindrical body for conducting exhaust gas, and a flat stainless steel foil 22 and a corrugated stainless steel foil 21
A honeycomb structure 24, which is formed by stacking corrugated stainless steel foils 23, is spirally loaded to constitute a metal carrier 20. The flat stainless steel foil 22 and the corrugated stainless steel foil 23 are joined by diffusion bonding or brazing, and have a structure that can withstand high-temperature and high-speed exhaust gas and rapid heating and cooling. As the cylinder 21, various shapes such as an elliptical shape as shown in FIG. 16 or a rectangular shape (not shown) as well as the circular shape in the present example have been conventionally proposed.

The above-described metal carrier 20 is, for example, shown in FIG.
As shown in FIG. 1, the cone-shaped air guide cylinder 25 is joined to both ends thereof by welding or the like, and a carrier 26 composed of the air guide cylinder 25 and the metal carrier 20 is generally connected to a manifold 27 for use. Reference numeral 28 denotes an exhaust pipe for discharging purified exhaust gas.

[0005] By the way, in the conventional general metal carrier, the metal carrier is not heated for about 30 seconds from the start of the engine and does not reach a temperature at which the catalyst functions sufficiently. Therefore, exhaust gas immediately after the start of the engine cannot be sufficiently purified. There was a disadvantage. To overcome this drawback, it is effective to heat the metal carrier in advance and raise the temperature to a temperature at which the catalyst functions before starting the engine.
No. 1, Japanese Patent Application Laid-Open No. 22362/1990.
As disclosed in Japanese Unexamined Patent Publication No. 2 (1993) -210, technical means for forming an electrode on the above-mentioned honeycomb structure and heating by applying an electric current have been conventionally proposed.

However, the technical means of winding a heater around the outer periphery of the metal carrier has a drawback that it takes time to heat the inside because the heating portion is only the outer periphery. Also, in the technical means for forming electrodes on the honeycomb structure, there is no means for forming an electric current path by providing an insulating layer. Therefore, when current is supplied to the center and the outer periphery of the honeycomb structure, only the current density at the center is high. Therefore, it is difficult to uniformly heat the metal carrier. On the other hand, when the outer peripheral portions are heated, only the outer peripheral portion is heated, which also has a disadvantage that uniform heating cannot be performed.

[0007] 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.
Further, as shown in FIG. 15, an insulating layer 29 is formed on the honeycomb structure 24 loaded in the cylindrical body 21 and the cylindrical body 2
Technical means for forming a current path having a resistance suitable for electric heating by providing electrodes 40a, 40b (40a is an anode and 41b is a cathode in this example) and insulating materials 41a, 41b are also known. is there. As an insulating material for forming the insulating layer 29, JP-A-3-500911 discloses a granular ceramic or a ceramic fiber mat. In FIG. 15, the arrow x indicates the direction of current flow.

Although the provision of such a metal carrier has improved the exhaust gas purification efficiency immediately after the start of the engine, the metal carrier has a high temperature exhaust gas in addition to the heat cycle in which the engine is repeatedly operated and stopped. Since the metal carrier is used in a harsh environment in which it passes through the inside at a high speed, the durability of the metal carrier itself is extremely low, which has been a major obstacle to practical use.

In particular, the position of the metal carrier as close as possible to the exhaust manifold 27 as shown in FIG. 17 is advantageous in terms of the exhaust gas temperature and the functionality of the catalyst, but the closer it is to the manifold 27, the better. Heat resistance as described above,
Demand for heat cycle resistance becomes severe. However, the insulating layer of the prior art using the above-mentioned granular ceramic or ceramic fiber mat has a fatal disadvantage that it is extremely weak against thermal shock due to a thermal cycle, and has been difficult to put into practical use.

It is also possible to use an oxide such as alumina or silica as an insulating layer in place of a granular ceramic or a ceramic fiber mat.
This is disclosed in Japanese Patent Publication No. However, the present inventors have confirmed in many experiments that simply coating alumina or silica or the like does not solve the above-mentioned drawback drastically.

That is, according to the conventional means, even if an insulating layer is formed, the insulating layer and the stainless steel foil forming the honeycomb structure are incompletely joined, so that the heat cycle resistance cannot be obtained. It was not possible to secure a durable durability.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a metal carrier comprising the above-mentioned honeycomb structure in which a flat stainless steel foil and a corrugated stainless steel foil are laminated in a cylinder having positive and negative electrodes. 80
Heat resistance to a high temperature of 0 ° C. or higher, heat cycle resistance to withstand a severe thermal cycle of a temperature difference of 800 ° C. or more between room temperature and a high temperature of 800 ° C. or more, electricity at a joint between a joined insulating material and a honeycomb structure It is an object of the present invention to provide a metal carrier that simultaneously satisfies the three properties of insulation.

[0013]

According to the present invention, there is provided a metal carrier comprising a honeycomb structure in which a flat stainless steel foil and a corrugated stainless steel foil are stacked in a cylindrical body having positive and negative electrodes. In the metal carrier, the melting point is between the adjacent flat stainless steel foil and the flat stainless steel foil in the honeycomb structure, or between the flat 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 thickness 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 arranged between the stainless steel foils constituting the honeycomb structure and fired. And 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 in the metal carrier is performed by brazing.

Further, the stainless steel foil constituting the stainless steel foil pair in the metal carrier is previously oxidized, or when brazing the oxidized stainless steel foil pair, the brazing material foil and the stainless steel foil are used. Ti or Zr between stainless steels forming a pair
Characterized by the presence of a foil.

Still 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 has at least 10% Cr or more. , Al at least 3%, or the stainless steel foil constituting the stainless steel foil pair has at least Cr 10% or more, Al 3% or more, and a lanthanoid element of 0.1% or more.
Another feature is that the content is at least 01% by weight.

[0017]

According to the present invention, in order to provide a metal carrier capable of withstanding the above-mentioned three characteristics, in particular, the severe thermal cycle of starting and stopping the engine, the insulating layer in the honeycomb structure is formed by the above-mentioned stainless steel foil pair. The melting point is 8 between the adjacent flat stainless steel foil and the flat stainless steel foil, between the flat stainless steel foil and the corrugated stainless steel foil, or between the corrugated stainless steel foil and the corrugated stainless steel foil.
The main feature is that an oxide having a temperature of 00 ° C. or more, 1400 ° C. or less and a thickness of 1 mm or less is interposed and then fired.

That is, the optimum range of the melting point of the oxide to be interposed between the stainless steel foils and the optimum thickness are clarified.
Strongly join the opposing stainless steel foil with the oxide in between,
Moreover, by electrically insulating the two stainless steel foils reliably, the electrical insulation required for the metal carrier,
This makes it possible to simultaneously satisfy three properties of heat resistance and heat cycle resistance.

FIG. 1 is a perspective view for explaining a basic structure of a metal carrier according to the present invention, and FIG. 2 is a view showing FIG. 1A-A '.
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 mounted on a cylindrical body 2 having a circular cross section. The cylinder 2 has an anode terminal 4 and a cathode terminal 5,
The anode terminal 4 is connected to an electrode rod 4b disposed substantially at the center of the cylindrical body 2 via a conductor 4a. Reference numeral 6 denotes an insulator for electrically insulating the cylindrical body 2 from the anode terminal 4, the conductor 4a and the like. The honeycomb structure 3 is configured by laminating a flat 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 (to be described later) is placed between adjacent flat stainless steel foils 7a and 7a.
The oxide 10 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 cylindrical body 2. Arrow y indicates the direction of current conduction in the current path. The flat 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 the same as that shown in FIGS.
In the embodiment of the present invention, the flat stainless steel foils 7a and 7a are used. For example, as shown in FIG. 4, an oxide 10 is placed between the adjacent flat stainless steel foil 7a and the corrugated stainless steel foil 8a.
And an oxide 10 between the corrugated stainless steels 8a and 8a adjacent to each other as shown in FIGS. 5 and 6, and a pair of stainless steel foils 11c and 1c.
Even if 1d is configured, the function of the present invention described later can be sufficiently exhibited.

The stainless steel foil pair 11 (hereinafter, the various stainless steel foil pairs are generally 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. It is arranged in. The honeycomb structure 3 and the stainless steel foil pairs 11 arranged in the honeycomb structure 3 are collectively referred to as a honeycomb core 30 hereinafter.

Next, means for forming the honeycomb structure 3 and the stainless steel foil pair 11 will be specifically described. In the embodiment of FIGS. 1 and 2, the electrode rod 4b located at the center of the cylinder 2 serves as an anode, and the terminal 5 located at the outer periphery of the cylinder 2 has a function as a cathode. 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 uniformly heated.

Now, 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 (a flat stainless steel foil 7a in this embodiment) is coated with an oxide 10 kneaded with an organic vehicle into a paste, and a coating layer of the oxide 10 is formed. Is prepared.

Next, as shown in FIG. 8, an ordinary flat stainless steel foil 7 and a corrugated stainless steel foil 8 constituting the honeycomb structure 3 are sequentially laminated. The flat stainless steel foil 70 having the coating layer of the oxide 10 is laminated in the opposite direction so that the oxides 10 are in contact with each other to form a stainless steel foil pair 11a, the flat stainless steel foil 7, and the corrugated stainless steel foil. 8 and are laminated.

It is preferable that a brazing filler metal (hereinafter referred to as a brazing filler metal foil) 12 is previously adhered to the front and back surfaces of the flat stainless steel foil 7 at predetermined intervals by an adhesive or spot welding. The flat stainless steel foil 7b is a flat stainless steel foil formed to be longer than the other flat stainless steel foils 7 by the circumferential length of the honeycomb core 30 in order to braze the cylindrical body 2 and the honeycomb core 30.

On the other hand, a cross-shaped notch 4c is formed in the electrode rod 4b as shown in FIG. As shown in FIG. 8, the stainless steel foils 7 and 8 and the stainless steel foil pair 11a which are stacked in the cut groove 4c to form a honeycomb core are collectively referred to as stainless steel foils. (Called a bundle)
Fix it. FIG. 10 is a cross-sectional view showing a state in which two sets of the stainless steel foil bundles are inserted into two opposing cut grooves 4c. In order to efficiently insert and insert the ends of the stainless steel foil bundle, it is effective to provide folds 7e, 8e, and 70e at the ends of each stainless steel foil as shown in FIG. is there. Further, a flat stainless steel 7 for brazing the above-described tubular body 2 and the honeycomb core 30 is used.
b is loaded on one side only.

Next, as shown in FIG. 11, the stainless steel foil bundle is wound around the electrode rod 4b. By this winding, the honeycomb structure 3 is formed, and a layer of the spiral oxide 10 is formed inside the honeycomb structure 3, thereby forming the honeycomb core 30. Then, in order to adjust the outer diameter of the honeycomb core 30 rolled up, the end of each stainless steel foil was appropriately cut, and the length was adjusted.
As shown in FIG. Thereafter, the conductor 4a, the anode terminal 4, and the cathode terminal 5 are connected to the electrode rod 4b, and the metal carrier 1 is formed by mounting the insulator 6.

In the above embodiment, the notch 4c of the electrode rod 4b is used.
Since the two sets of the stainless steel foil bundles are respectively inserted into the above, two layers of the spiral oxide 10 starting from the electrode rod 4b are formed as shown in FIG. On the other hand, when the stainless steel foil bundle is inserted into only one of the notches 4c as shown in FIG.
As shown in FIG. 2, a layer of a series of spiral oxides 10 can be formed.

The metal carrier 1 formed by the above-mentioned means is
For example, it is heated at 1200 ° C. in a vacuum atmosphere and fired. By this baking, the brazing filler metal foil 12 is melted, the flat stainless steel foil 7a and the corrugated stainless steel foil 8b are joined, and the oxide 10 also melts in the stainless steel foil pair 11a, reacting with the stainless steel foil 7a and reacting with the flat stainless steel foil 7a. The stainless steel foils 7a are firmly joined together, and an insulating layer 9 of a fired oxide is formed between the flat stainless steel foils 7a.

As described above, the oxide 10 interposed between the stainless steel foil pairs 11 is fired to form the insulating layer 9, and the stainless steel foil disposed opposite to the oxide 10 is firmly fixed. Demonstrate the function of joining.

By the way, in the metal carrier 1, since the exhaust gas passes through the honeycomb core 30 at a high speed during the operation of the engine, especially when the bonding strength between the insulating layer 9 and the stainless steel foil is low, the honeycomb core 30 is formed by the gas flow. A phenomenon of deviation in the flow direction occurs. If this displacement is large, the electricity cannot be supplied due to the cutting of the stainless steel foil constituting the honeycomb core 30,
Alternatively, the metal carrier 1 cannot be heated uniformly due to insulation failure or the like due to destruction 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 at 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 displacement of the honeycomb core 30 and can provide heat resistance.

As described above, a thermal cycle occurs when the engine is operated and stopped, but if the insulating layer 9 is broken by the thermal cycle, the honeycomb core 30 may be displaced. First, in order to obtain the heat cycle resistance of the insulating layer 9,
The oxide itself needs to be thin. The value of this upper limit is 1 mm. In order to withstand a thermal cycle at room temperature and 800 ° C., the melting point of the oxide needs to be 1400 ° C. or less.

If the thickness of the oxide exceeds 1 mm, breakage tends to occur due to the difference in thermal expansion between the oxide and the stainless steel foil. When the melting point of the oxide is set to 1400 ° C. or lower, the oxide can be deformed at a relatively low temperature, thereby absorbing a thermal shock. However, when the melting point exceeds 1400 ° C., the deformability of the oxide is reduced. Since the insulating layer 9 is insufficient, the insulating layer 9 is broken by the heat cycle, and the displacement of the honeycomb core 30 increases.

Examples of oxides satisfying the above characteristics include A
l ₂ O ₃ —SiO ₂ system, MgO—SiO 3 system, 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 oxidize the stainless steel foil constituting the stainless steel foil pair 11 in advance. 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 effective means to interpose a Ti or Zr foil 13 on the surface of the brazing material foil 12 in contact with the oxidized stainless steel foil 70 as shown in FIG.

The unevenness of the surface of the stainless steel constituting the stainless steel foil pair is effective for improving the heat cycle resistance of the metal carrier.

In the stainless steel used in the present invention, particularly in a stainless steel foil constituting a stainless steel foil pair, if Al is contained in an amount of 1% by weight or more, a dense alumina film is formed on the surface. In the case of oxides of iron and nickel, where the oxide is formed is at the interface between the oxide and the gas phase and the film grows outward, the adhesion to the metal substrate is not very good. Since the oxide film grows toward the inside, the adhesion of the stainless steel foil itself to the metal substrate becomes very good. Therefore, the bonding strength between the oxide forming the insulating layer and the stainless steel foil is improved, which is advantageous for reducing the amount of misalignment of the honeycomb core.

Further, the stainless steel foil constituting the stainless steel foil pair is composed of at least 10% or more of Cr and 3% of Al.
%, 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. If the lanthanoid element contains 0.01% by weight or more in addition to Cr and Al, the oxide film becomes thick only in the portion where the lanthanoid element is segregated. Since a wedge is formed in the surface, an excellent effect is exhibited in that the adhesion of the oxide film is further improved.

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

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

Thus, in the metal carrier 1a of the present embodiment, the cathode terminal 5 is connected from the cylindrical upper plate 2a1 connected to the anode terminal 4 via the honeycomb structure 3a divided by the insulating layer 9a.
A 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 of FIG. 13. The cylindrical body 2b is made of an insulating material such as a ceramic plate. Is a flat stainless steel foil 7 as in FIG.
And a honeycomb structure 3b formed by laminating a corrugated stainless steel foil 8 with the honeycomb structure 3b. The insulating layer 9b is
Are opened so that the end portions of the honeycomb structure 3b divided by are alternately contacted. Such an insulating layer 9b is formed of a pair of stainless steel foils (in this embodiment, two flat stainless steel foils 7).
It is possible to easily form it by adjusting the length of 11a and arranging it in the honeycomb structure 3b.
The anode terminal 4 and the cathode terminal 5 are connected to the honeycomb structure 3.
b and is electrically conductive.

[0046]

【Example】

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

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

As the oxide 10, an oxide obtained by adding boron, manganese, calcium, magnesium or the like to an Al ₂ O ₃ —SiO ₂ based oxide and adjusting the melting point was used. In the present embodiment, a powdery material having an average particle diameter of 10 μm and having a melting point adjusted to a range of 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.

The flat stainless steel foil 7 and the corrugated stainless steel foil 8 constituting the honeycomb structure 3 have a thickness of 50 mm.
A stainless steel foil (approximately 500 mm long) equivalent to SUS430 having a width of 17 μm and a width of 17 mm was prepared and laminated as shown in FIG.
On the front and back surfaces of the flat stainless steel foil 7, a Ni-based brazing material foil (BNi-5) 12 having a size of 10 × 10 mm and a thickness of 25 μm is 15 mm.
It was stuck at intervals. The brazing material foil 12 that is coated with the oxide 10 and is disposed so as to be in contact with the oxide coated surface and is in contact with the stainless steel foil 70 in which the stainless steel foil pair 11 is formed,
As described above, a 10 mm × 10 mm Ni-based brazing material foil having a thickness of 25 μm is adhered at an interval of 40 mm, and 10 mm outside the Ni-based brazing material foil.
A Ti foil 13 having a size of 10 mm and a thickness of 5 μm was stuck. One end of each stainless steel foil is bent upward by 3 mm at a right angle to form folds 7e, 8e, and 70e.

The laminated stainless steel foil bundle was formed on the honeycomb core 30 in the manner described above with reference to FIGS. 9 to 11, and was loaded on the cylindrical body 2 to produce the metal carrier 1. The electrode rod 4b
Is made of a Ni rod having a diameter of 8 mm and a length of 50 mm. A cross-shaped notch 4 c having a width of 1 mm and a length of 17 mm is formed at one end of the electrode rod 4 b.

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

The metal carrier 1 was mounted on a test device similar to that shown in FIG. 17, and the amount of displacement of the core after a thermal cycle load was examined. Air guide cylinders 25 were fixed to both ends of the metal carrier 1 by welding in order to mount the test apparatus.

The test conditions were such that the temperature of the metal carrier 1 was raised to 850 ° C. in 10 minutes after the operation of the engine, the engine was stopped, and then 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 performed using the honeycomb core 30
Was evaluated by the amount of displacement (deviation) from the original position. Table 1 shows an example of the result of the investigation. The deviation amount after applying the thermal cycle load 900 times was examined. If the deviation amount was within 1 mm, the result was acceptable (O), and the deviation exceeded 1 mm. Are shown as failed (x).

As a comparative example, the results of a similar test in which a metal carrier was produced using a commercially available inorganic adhesive in place of the oxide and the same test is also shown.

[0056]

[Table 1]

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

In the metal carrier of the present invention, the temperature rise performance by energization is 400 ° C. when 2.5 kW of electric power is used.
Was 7 seconds, and it was also confirmed that this point was enough for practical use.

Example 2 In Example 1, the stainless steel foil constituting the stainless steel foil pair 11 was made of Fe-10Cr-
The stainless steel foil was subjected to mechanical unevenness by sandblasting, anodization in sulfuric acid, or yttrium ion implantation, and after this treatment, a paste of an intervening oxide was applied, or After pre-oxidation at 60 ° C for 60 minutes,
The metal carrier 1 was manufactured in the same manner as in Example 1 except that the oxide 10 was applied, and the above test was performed. Incidentally, the thickness of the oxide 10 was fixed at 40 μm. Table 2 shows an example of the survey results.

From the results in Table 2, it was found that the oxides having the melting point in the range of the present invention were within 1 mm even if the displacement occurred, and the pre-oxidized ones It turns out that it is excellent compared with the thing which is not performed.

[0061]

[Table 2]

[0062]

As described above, the metal carrier of the present invention has a high heat cycle resistance against a heat cycle of engine stoppage, which has been impossible so far, and at the same time, has a heat resistance. A metal carrier capable of uniform heating was obtained.

[Brief description of the 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 sectional view taken along line AA ′ of FIG.

FIG. 3 is an enlarged view of a portion A in FIG. 2;

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

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

FIG. 6 is a partial sectional view showing still another example of the 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 diagram showing a laminated state of a flat stainless steel foil, a corrugated stainless steel foil, and a stainless steel foil pair.

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

FIG. 10 is a schematic view showing a state in which a stainless steel foil bundle is mounted on an electrode rod.

FIG. 11 is a schematic view showing a state where a stainless steel foil bundle is wound around an electrode rod.

FIG. 12 is a sectional structural view showing a basic structure of a metal carrier in which an insulating layer is one series.

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 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 foil 23 Corrugated stainless steel foil 24 Honeycomb structure 25 Air guide cylinder 26 Carrier 27 Manifold 28 Exhaust pipe 29 Insulating layer 40a Anode terminal 40b Cathode terminal 41a, 40b Insulator

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-246174 (JP, A) JP-A-3-500911 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 21/00-37/36 B01D 53/86 F01N 3/28

Claims (7)

(57) [Claims] 1. An exhaust gas purifying catalyst metal carrier for an automobile equipped with a current-carrying heating device in which a honeycomb structure in which a flat stainless steel foil and a corrugated stainless steel foil are laminated is loaded in a cylindrical body having positive and negative electrodes. In the honeycomb structure, an oxidation having a melting point of 800 ° C. or more and 1400 ° C. or less and a thickness of 1 mm or less between adjacent flat stainless steel foils, between a flat stainless steel foil and a corrugated stainless steel foil, or between corrugated stainless steel foils. A stainless steel foil pair is formed with an intervening object, and the stainless steel foil pair is disposed between the stainless steel foils constituting the honeycomb structure, and then fired to form an insulating layer. Metal carrier for automotive exhaust gas purification catalyst. 2. The metal carrier for an automotive exhaust gas purifying catalyst according to claim 1, wherein the stainless steel foil pair and the honeycomb structure are joined by brazing. 3. The stainless steel foil constituting the stainless steel foil pair has been previously oxidized.
Alternatively, the metal carrier for an automobile exhaust gas purifying catalyst according to any one of the above items 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 constituting the stainless steel foil pair. 4. The metal carrier for an automobile exhaust gas purifying catalyst according to 3. 5. The metal for an automotive exhaust gas purifying catalyst according to claim 1, wherein the stainless steel foil constituting 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% or more of Cr and 3% or more of Al.
5. The metal carrier for an automobile exhaust gas purifying catalyst according to any one of the above items. 7. The stainless steel foil constituting the stainless steel foil pair contains at least Cr 10% or more, Al 3% or more, and a lanthanoid element 0.01% by weight or more. 5. The metal carrier for an automobile exhaust gas purifying catalyst according to any one of the above items 4.