JP2933392B2 - Brazing method for heat-resistant alloy having insulating oxide film on surface, preheated metal carrier for exhaust gas purification, and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for brazing a heat-resistant alloy, and more particularly to a method for brazing a heat-resistant alloy having an insulating oxide film on a surface, and a metal carrier for exhaust gas purification excellent in purification performance manufactured by using the technique.

BACKGROUND ART In automobile exhaust gas purifying catalysts, generally, Pt, Rh, Pd
And the like. In order for the catalyst to function, the catalyst needs to be heated to a temperature of about 350 to 400 ° C. A catalytic converter widely used at present has a catalyst supported on a ceramic carrier or a metal carrier, and is a method of heating and activating the catalyst by the thermal energy of the exhaust gas itself. Therefore, the time from when the engine starts until the temperature at which the catalyst functions is long,
There was a disadvantage that the purification performance immediately after starting the engine was poor.

However, with the recent tightening of exhaust gas regulations, a catalytic converter having excellent purification performance immediately after engine start, that is, at the time of cold start has been desired. As a countermeasure, at least one of the honeycomb structured flat plate (flat thin plate) and the corrugated plate (corrugated thin plate) constituting the metal carrier is covered with an insulating film, and electrically insulated from each other. There is a method of forcibly heating the catalyst with Joule heat generated by energizing in a spiral direction to shorten the time required to reach the catalyst functional temperature.

JP-T 3-500911 discloses a metal carrier having an insulating layer provided in a honeycomb structure composed of a flat plate and a corrugated plate and having a resistance value suitable for electric heating. FIG. 1 shows an example of the structure disclosed in the above publication. In this structure, insulating layers 180 are arranged at appropriate intervals in a honeycomb structure 151,
This forms a current path as indicated by an arrow. The power consumed in the current path is controlled between 50 and 500W. This is the power that can be reasonably supplied from a car battery.
However, the electrically heated part is the aforementioned flat plate,
As in the case where the insulating film is applied to the corrugated sheet, the entire honeycomb structure is required, and it takes a long time to reach a desired temperature.

Japanese Patent Application Laid-Open No. 5-59939 discloses a metal carrier having a structure in which a heater is embedded in a honeycomb structure. In this configuration, only the embedded heater is electrically heated. However, actually, when the catalytic reaction starts, a combustion reaction occurs, for example, represented by 2CO + O ₂ = 2CO ₂ . The reaction is exothermic and generates a large amount of heat. That is, if only a part of the honeycomb structure is heated to a temperature at which the supported catalyst functions, after the reaction starts in the heated part, the other parts are naturally heated quickly by the heat of reaction. In this case, the electrically heated volume is small compared to the reference, so that when the same power is applied, the catalyst in the heated part reaches the functional temperature in a short time.

However, even in the method described in Japanese Patent Application Laid-Open No. 5-59939, a honeycomb having a hole or a groove for embedding a heater for heating is manufactured and then processed into a shape suitable for the hole or the groove. However, there is a drawback that the manufacturing method for embedding the heater is forced to take a complicated manufacturing process.

The present invention solves the above problems particularly in a preheated metal carrier. That is, an object of the present invention is to firmly join a heat-resistant alloy having an insulating film on its surface (hereinafter referred to as an insulating-coated heat-resistant alloy).

Another object of the present invention is to provide good electrical conductivity to a joint of an insulating coated heat-resistant alloy.

Another object of the present invention is to provide a preheated exhaust gas purifying catalyst metal carrier having a honeycomb structure in which at least one of a flat plate and a corrugated plate is formed of an insulating coated heat-resistant alloy, and the inside of the honeycomb structure can be energized by an extremely simple structure. Where you do it.

Another object of the present invention is to allow a portion of the inside of the honeycomb structure to be energized to enable preheating of the metal carrier.

Another object of the present invention is to sufficiently join the flat plate and the corrugated plate in the honeycomb structure.

Configuration of the Invention The present invention provides the following technology to achieve the above object.

In a honeycomb structure in which at least one of a flat plate and a corrugated plate constituting a honeycomb structure is coated with an insulating film and is electrically insulated from each other, a brazing method for electrically connecting a part between the flat plate and the corrugated plate is provided. Can form a honeycomb structure in which only the path having the joining portion becomes a heat generating portion.

However, joining that can be performed by a generally used brazing method is limited to those having no insulating film formed on the surface of the heat-resistant alloy. The reason for this is that if an insulating film is present, the fusion of the brazing material and the heat-resistant alloy is inhibited by the insulating film even if the brazing material melts.
Therefore, there is a need for a technique for joining a heat-resistant alloy having an insulating film on its surface (insulating-coated heat-resistant alloy) so that the joint has electrical conductivity.

In order to solve the above-described problems, the present invention uses a joining material obtained by laminating a strong reducing metal (eg, Zr) and a brazing material when joining an insulating coating heat-resistant alloy (eg, a heat-resistant alloy containing Al) and a heat-resistant alloy, The above-mentioned strongly reduced metal surface is arranged on the side of the insulating coating heat-resistant alloy to form a laminate, and then heated and brazed in a non-oxidizing atmosphere.

When joining the insulating coated heat-resistant alloys to each other, a joining material in which a brazing material is interposed between a pair of strongly reduced metals is used to form a laminate, and then heated and brazed in a non-oxidizing atmosphere.

According to the above joining method, a metal carrier having a joining portion through which a honeycomb structure in which at least one of a corrugated plate and a flat plate is made of an insulating-coated heat-resistant alloy can be conducted can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a preheated metal carrier according to the prior art.

FIG. 2 is a partially sectional front view showing the laminate of the present invention.

FIG. 3 is a partial cross-sectional front view schematically showing a joint when the laminate of FIG. 2 is joined.

FIG. 4 (a) is a plan view of the metal carrier of the present invention as viewed from the exhaust gas entry side.

 FIG. 4 (b) is a sectional view taken along line AA of FIG. 4 (a).

FIG. 5 is a schematic cross-sectional view of the vicinity of the joint portion of the metal carrier shown in FIGS. 4 (a) and 4 (b).

FIG. 6 is a perspective view of a metal carrier having a conductive path formed by laser beam welding.

FIG. 7 is a partially sectional front view showing a laminated body according to another embodiment of the present invention.

FIG. 8 is a partial cross-sectional front view schematically showing a joint when the laminate of FIG. 7 is joined.

 FIG. 9 is a partial cross-sectional front view of the laminate of the comparative example.

FIG. 10 is a partial cross-sectional front view schematically showing a joint when the laminate of FIG. 9 is joined.

FIG. 11 is a partially sectional front view showing a laminate according to another embodiment of the present invention.

FIG. 12 is a schematic view showing a process of forming a metal carrier by the method of the present invention.

FIG. 13 is a plan view showing a metal carrier formed by the method of FIG.

FIG. 14 is a sectional front view of a catalytic converter constituted by the metal carrier of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described.

To insulate between the heat-resistant alloys, at least one of the corrugated plate and the flat plate may be coated with an insulating film. For the insulating coating, a known technique such as PVD, CVD, ceramic spraying or ceramic powder coating can be used. More preferably, a heat-resistant alloy containing Al is used, and the heat-resistant alloy is used at 1000 ° C or higher ( (Lower than the melting point) at a temperature of high temperature to form an oxide film on the surface. When a high-temperature oxidation treatment is applied to a heat-resistant alloy containing Al, an oxide film containing alumina as a main component, which is dense and has good adhesion and has a high insulating function, is generated. However, as described above, it is impossible to join between the heat-resistant insulating coating alloy and the heat-resistant alloy or between the heat-resistant insulating coating alloys, as described above.

Therefore, as a result of repeated experiments and researches, the present inventors have found that a joining material in which a metal capable of thermodynamically reducing an insulating film (hereinafter referred to as a strong reducing metal) and a brazing material are laminated between a heat-resistant insulating coating alloy and a heat-resistant alloy. It has been found that when the strong reducing metal (for example, foil) is arranged in contact with the heat-resistant insulating coating alloy and heated in a non-oxidizing atmosphere, the strong reducing metal foil reduces the insulating film. In addition, it was possible to obtain a joining strength equivalent to that obtained by brazing heat-resistant alloys having no insulating coating to each other, and to obtain a result that the joining portion becomes a conductive path.

The joining mechanism will be described for a case where an oxide film containing alumina as a main component is used as an insulating film and Zr is used as a strong reducing metal. First, alumina and Zr foil, which are the main components of the insulating film, cause a substitution reaction represented by 2 / 3Al ₂ O ₃ + Zr = 4 / 3Al + ZrO ₂ . At the same time, the brazing material is melted. The generated ZrO ₂ is dispersed and precipitated in the molten brazing material.
The molten brazing alloy is alloyed with Zr, passes through the gap of ZrO ₂ dispersed and deposited, reaches the base material of the heat-resistant insulating coating, and is joined by the same mechanism as ordinary brazing. Generated at the same time
Al dissolves in the brazing filler metal or diffuses into the insulation-coated heat-resistant alloy. By this mechanism, the insulating coated heat-resistant alloy is joined, and the joint has conductivity.

Now, a specific configuration of the present invention will be described. FIG. 2 is a schematic partial cross-sectional view of a laminate for explaining an example of a joining method according to the present invention, and FIG. 3 shows an example of a joined body generated based on the laminate of FIG. It is a partial sectional view.

In FIG. 2, reference numeral 2 denotes an insulating-coated heat-resistant alloy having an insulating film 3 (hereinafter simply referred to as an oxide film) mainly composed of alumina formed on the surface. Reference numeral 4 denotes a heat-resistant alloy whose surface is not oxidized (hereinafter referred to as a heat-resistant alloy). The oxide film 3 is preferably obtained by heating in an oxidizing atmosphere because of the simplicity of the manufacturing method, and the method of heating in the air is most preferable. In that case, it is necessary that Al is contained in the insulating coating heat-resistant alloy 2.

Reference numeral 7 denotes a joining material formed by laminating the strong reducing metal 5 and the brazing material 6. The bonding material 7 is disposed such that the strongly reduced metal 5 is in contact with the oxide film 3, and the laminated body 1 is composed of the heat-resistant alloy 2 and the heat-resistant alloy 4. The strong reducing metal 5 is a metal capable of reducing alumina, specifically, Zr, Li, Be, Mg, Ca, Sr,
Sc, Y, and at least one of the lanthanoid elements with atomic numbers 57-71 are used. Note that elements other than the above elements may be contained to the extent that the oxide film 3 can be reduced. In particular, Zr is advantageous in that foil rolling is easy as compared with other elements, and therefore, formation of a bonding material is easy.

The laminate 1 is heated in a non-oxidizing atmosphere. By this heating operation, the brazing material 6 is melted, and the oxide film 3 is reduced by the strong reducing metal 5. After the cooling, as shown in FIG. 3, a joint portion 11 having a structure in which the strongly reduced metal oxide 10 is dispersed and precipitated is formed in the brazing portion 9. In addition, the oxide film 3 has disappeared at the joint 11. The brazing portion 9 has a structure in which the strongly reduced metal and the brazing filler metal are alloyed. When a Ni-Si-Cr brazing material and Zr as a strong reducing metal are used, the brazing portion 9 exhibits a structure mainly composed of two phases of a phase composed of Ni-Si-Zr and a phase composed of Cr.

Thus, the insulating coating heat-resistant alloy 2 and the heat-resistant alloy 4 are joined by the joint 11 to form a joined body 8. Since the brazing portion 9, which is a metal component, is a matrix, the joining portion 11 can be energized and also functions as a conductive path.

Up to this point, the joining of the heat-resistant insulating coating alloy 2 and the heat-resistant alloy 4 has been described, but the same technical means can be applied to the joining of the heat-resistant insulating coating alloys. In this case, a joining material in which a brazing material is sandwiched between two strongly reduced metals may be used. The joining mechanism is the same as described above.

Further, by using the technical means of the present invention, the above-mentioned preheated metal carrier for purifying exhaust gas can be manufactured. 4th
Figure (a) is a schematic plan view of the metal carrier, and Figure 4 (b)
FIG. 4 is a sectional view taken along the line AA in FIG. Metal carrier 12
Is composed of a honeycomb structure 15 composed of, for example, a corrugated sheet 13 of an insulation-coated heat-resistant alloy, and a flat plate 14 of a heat-resistant alloy, a center electrode rod 16, and an outer cylinder 17, which are joined to an exhaust gas entering side portion in the honeycomb structure. It has a part 11.

In order to form the bonding portion 11, a bonding material 7 composed of a strong reducing metal 5 and a brazing material 6 is applied to a portion where a conductive path between the corrugated plate 13 and the flat plate 14 is to be formed before the heat treatment for brazing. In advance.

FIG. 5 is an enlarged schematic view of the vicinity of the joint 11 in FIGS. 4 (a) and 4 (b). As in the above description, a strong reduced metal oxide 10 is dispersed and precipitated in the brazing portion 9. When a voltage is applied between the center electrode rod 16 and the outer cylinder 17 of the metal carrier 12 shown in FIGS. 4 (a) and 4 (b), the current flows in the direction indicated by an arrow because the junction 11 is a conductive path E. It flows in the Y direction, and only the portion of the conductive path E generates heat. Since the volume to be heated is very small as compared with the method of heating the entire metal carrier, the catalyst activation temperature can be reached in a short time.

When the catalyst is actually loaded on the metal carrier 12 and the exhaust gas is flown and the energization is started at the same time, the reaction starts shortly after the energization, and the reaction quickly proceeds from the joint 11 to other parts due to the reaction heat. spread.

Another advantage of using the brazing method is that a joint of the desired shape and size is obtained. For example, when the honeycomb structure 15 is formed without disposing the joining material, and then the end face 18 of the honeycomb structure 15 is welded with a laser beam 200 or the like as shown in FIG. 6, a conductive path is also formed. Since the welding depth is not constant, the conduction resistance differs for each joint and the amount of generated heat differs, so that abnormal heat is partially generated and the joint burns out.

Although the case where the corrugated plate 13 is a heat-resistant alloy and the flat plate 14 is a heat-resistant alloy has been described above, a combination in which the corrugated plate 13 is a heat-resistant alloy and the flat plate 14 is a heat-resistant insulating metal plate, or a corrugated plate or a flat plate Can be considered a combination in which both are heat-resistant insulating coatings, but strongly reduced metal 5 and oxide film 13-1
By selecting a bonding material that makes contact with each other and forming the bonding portion 11, a metal carrier 12 having the same performance can be manufactured.

EXAMPLES Example 1 The following test was performed to grasp the strength and electrical conductivity of the joint, which are expected effects of the present invention.

As shown in FIG. 7, a 1 mm thick, 100 mm long, 17 mm wide heat-resistant alloy SUS430 plate 40, 15 mm long, 15 mm wide, 25 μm thick
m BNi-5 brazing material foil (Ni-19Cr-10Si) 60,
Zr foil, a strong reducing metal with a length of 15mm, a width of 15mm and a thickness of 5μm
50 and heated at 1100 ° C for 60 minutes in air, 1μm on the surface
Thick alumina-based oxide film 30 was formed, a length of 100 mm, a width of 17 mm, and a 1 mm-thick Fe-20Cr-5Al-based insulating coated heat-resistant alloy plate 20 were sequentially laminated to produce a laminate 80. did.
Thereafter, the laminate 80 is fixed with a jig, and heated at a temperature of 1200 ° C. for 10 minutes in a vacuum atmosphere.
Was prepared. 100 is a strongly reduced metal oxide and 110 is a joint.

Thereafter, a load was applied in the direction of the arrow to the joined body 90, that is, the heat-resistant alloy 40 and the insulating coating heat-resistant alloy 20, and the bondability was measured.The heat-resistant alloy 40 was destroyed by a load of about 1000 kg, and the joint 110 was formed. It was sound. When the oxide film 30 on the side opposite to the joint 110 of the insulating coating heat-resistant alloy 20 was removed and a current test was performed, the resistance value was 1 mΩ or less, indicating high conductivity.

When the joint 110 was observed under a microscope, the oxide film 3 was observed.
0 completely disappeared, and dispersion precipitation of Zr oxide 100 was observed.

As a comparative example, the Zr foil 50 was not arranged as shown in FIG.
When brazing was performed using only 60, the disappearance of the oxide film 30 at the joint 210 was not recognized as shown in FIG.
It was broken by a low load of about 100 kg, and the broken part was the interface between the joint 110a and the oxide film 30.

Example 2 In the same configuration as in Example 1, as a strong reducing metal,
When the same test as in Example 1 was performed using a powder of Mg, which is an element capable of thermodynamically reducing alumina, solidified with a binder and formed into a plate having a thickness of about 20 μm,
In the strength test, the heat-resistant alloy 40 was broken by a load of 1000 kg.
Also, the resistance value was 1 mm or less. In the joint structure, the alumina film had disappeared and Mg oxide was dispersed and precipitated.

As a comparative example, when a Ni foil having a thickness of 5 μm, which is an element that cannot thermodynamically reduce alumina, was used at the position of the strong reducing metal, the reduction reaction of alumina did not occur in the structure of the joint. In the strength test, the heat-resistant alloy was broken at a low load of 100 kg.

Example 3 As shown in FIG. 11, a pair of Zr foils 50 were inserted between a pair of Fe-20Cr-5Al-based insulating coated heat-resistant alloy plates 20 having a 1 μm oxide film 30, and a pair of Zr BNi in the middle of foil 50
A laminated body 80a having the same shape as in Example 1 was prepared by sandwiching a brazing filler metal foil 60 of -5 standard, and a bonded body was prepared and tested in the same manner as in Example 1. The coated heat-resistant alloy foil 20 was broken, and the joint was sound.
Also, the resistance value was 1 mΩ or less.

Embodiment 4 Next, a description will be given of a manufacturing process and an effect of a metal carrier by the above-described joining means. In FIG. 12, reference numeral 20b denotes an insulating coating heat-resistant alloy corrugated foil of an Fe-Cr-Al type or the like having a width of about 1 mm and a width of about 17 mm and a thickness of about 50 μm on which an oxide film having a thickness of about 1 μm is formed, and 40b represents Fe. -Cr-Al-based or Fe-Cr-based heat-resistant alloy flat foil, and 130 is a center electrode. The insulating coating heat-resistant alloy 20b and the heat-resistant alloy foil 40b are fixed to the center electrode rod 130 by means such as welding.

Next, the insulating coated heat-resistant alloy corrugated foil 20b and the heat-resistant alloy flat foil 40b are wound around the center electrode rod 130 to form the honeycomb structure 150 shown in FIG. At this time, a length of 10 mm is previously set at a position where the bonding portion 110b is to be formed in the honeycomb structure 150.
Strong reducing metal foil 50b with width of 1mm and thickness of about 5μm and thickness of 25μm
The bonding material 70b made of the brazing material foil 60b conforming to the BNi-5 standard or the like is appropriately arranged such that the strongly reduced metal foil is in contact with the insulating coated heat-resistant alloy foil. Before the winding, the arrangement may be fixed to the heat-resistant alloy foil 40b or the like in advance, or may be sequentially sandwiched in the winding process.

After the formation of the honeycomb structure 150 is completed, the outer cylinder 140 is disposed outside the honeycomb structure, and then heat treatment for brazing is performed in a vacuum. The heating temperature is set to a temperature suitable for the composition of the brazing material (melting temperature of the brazing material). For example, BNi-
1150 ~ 1250 ℃ for 5 series brazing material (Ni-19Cr-10Si)
It is about.

After the heat treatment, the end of the center electrode rod 130 is taken out of the outer cylinder 140 (extraction electrode 131), and the metal carrier 120 is completed.
At this time, the extraction electrode 131 and the outer cylinder 140 must be electrically insulated. After the metal carrier 120 is completed,
A catalyst is supported on the honeycomb structure.

The insulation-coated heat-resistant alloy foil 20b and the heat-resistant alloy foil 40b that constitute the honeycomb structure 150 are insulated from each other and are joined at a joint 110b located on the exhaust gas entry side. 1
The size of the two joints is, for example, about 10 mm in width and about 1 mm in depth when viewed from the exhaust gas entry side. The volume of the honeycomb structure 150 is preferably, for example, about 100 cc.
The bonding portion 110b of the metal carrier thus formed has a structure in which the strongly reduced metal oxide is dispersed and precipitated.

Now, when the exhaust gas is passed at the same time as the metal carrier 120 is actually energized, the junction 110b reaches the catalyst activation temperature in about 1 second, and an exothermic reaction occurs in this portion. Then, the periphery of the joint 110b is heated by the reaction heat from the portion, the catalytically active region is quickly expanded, and the entire metal carrier 120 reaches the catalytically active temperature in a short time.

As shown in FIG. 14, the entire catalytic converter 170
The main catalyst carrier 160 having a capacity of about 1000 cc is disposed downstream of the metal carrier 120 manufactured by the above method. In addition to the function of purifying the exhaust gas itself, the former-stage metal carrier 120 also has an effect of shortening the time until the catalyst of the main catalyst carrier 160 becomes active due to the exhaust gas heated by the exothermic reaction. .

Example 5 The following test was performed on a catalytic converter 170 having eight conductive paths each having a width of 10 mm and a depth of 1 mm and having a metal carrier 120 having a honeycomb structure having a capacity of 100 cc. Electrode 130
A power of 750 W was applied between the outer cylinder 140 and the outer cylinder 140, and the heating performance at that time and the purification performance of hydrocarbon (HC) in exhaust gas were investigated. The temperature rise performance was the time required for the junction 110b to reach 400 ° C., and the purification performance was purified in 20 seconds after the start of energization.
The evaluation was based on the HC purification rate. As a comparative example, the heating performance and the purification performance when a power of 750 W was applied to a metal carrier having a capacity of 100 cc and configured to heat the entire honeycomb structure shown in FIG. 1 were also investigated.

Table 1 shows the test results. In the catalytic metal carrier according to the present invention, only about one second after the start of energization, only the joint 110b generated heat and reached a temperature of about 400 ° C. The purification rate of HC was 48% for 20 seconds after the start of energization, and the purification rate without electricity was 33%, indicating an improvement in the HC purification rate of nearly 50%. In the comparative example, it took about 12 seconds to reach 400 ° C and the HC purification rate was 3
The rate of improvement was 7%, which was less than 20% as compared with the case where no current was supplied.

Example 6 The metal carrier 120 according to the invention in Example 4
Was examined for heat cycle resistance. ON-OF to apply 750W electric power for 10 seconds to heat the joint and then cool for 10 minutes
The F cycle was repeated. As a comparative example, a similar test was performed on a honeycomb structure end face formed with a conductive path by laser beam welding without using a brazing material based on FIG.

The results are shown in Table 2. In the metal carrier of the present invention, no deterioration was observed in the joint even after 5000 ON-OFF cycles were loaded, whereas in the comparative example, the ON-OFF cycle was burned out in the conductive path in 10 times, and the current could not be supplied. became.

Example 7 In addition, when using a heat-resistant alloy foil as an insulating coating as a flat plate and a heat-resistant alloy foil as a corrugated sheet, in a case where an insulating coated heat-resistant alloy is used for both the flat plate and the corrugated sheet, the oxide film and the Zr foil are in contact with each other. When a bonding material was selected and the same test as in Example 4 was performed, it was confirmed that the obtained honeycomb structure had almost the same current-carrying function and hydrocarbon purification performance as in Example 4.

INDUSTRIAL APPLICABILITY As described above, when manufacturing a metal carrier having high purification performance with low power, joining of an insulating coated heat-resistant alloy, which was not possible conventionally, becomes possible by the present invention, Since only the portion where the conductive path is desired to be formed can be joined, a preheated exhaust gas purifying metal carrier exhibiting extremely high purification performance can be obtained.

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI B23K 1/20 B01D 53/36 C (56) References JP-A-2-26643 (JP, A) JP-A-5-200305 (JP, A JP-A-5-200306 (JP, A) JP-A-3-501363 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23K 1/00-3/08 B01J 35 / 04 311 B01D 53/36

Claims (8)

(57) [Claims] When joining a heat-resistant alloy with an insulation-coated heat-resistant alloy, a bonding material obtained by laminating a strongly reduced metal and a brazing material is bonded to the insulation-coated heat-resistant alloy in a state in which the strongly reduced metal surface is in contact with the surface of the insulation-coated heat-resistant alloy. A method of brazing a heat-resistant alloy, comprising inserting a laminate between the alloy and a heat-resistant alloy to form a laminate, heating the laminate in a non-oxidizing atmosphere, and brazing. 2. The method of joining insulating coated heat-resistant alloys,
A bonding material in which a brazing material is interposed between a pair of strong reducing metals is inserted between the insulating-coated heat-resistant alloy to form a laminate, and the laminate is heated in a non-oxidizing atmosphere and brazed. A brazing method for heat-resistant alloys, comprising: 3. The method for brazing a heat-resistant alloy according to claim 1, wherein the heat-resistant alloy with an insulating coating is produced by heating a heat-resistant alloy containing Al at a high temperature in an oxidizing atmosphere. 4. The method according to claim 1, wherein the strongly reduced metal is at least one of Zr, Li, Be, Mg, Ca, Sr, Sc, Y or a lanthanoid element having an atomic number of 57 to 71. , 2 or 3. 5. The method for brazing a heat-resistant alloy according to claim 1, wherein the heat-resistant alloy or the heat-resistant alloy is a plate or a foil. 6. The brazing method for a heat-resistant alloy according to claim 1, wherein one of the heat-resistant insulating coating alloy and the heat-resistant alloy is a corrugated sheet. 7. A flat plate whose at least one surface is covered with an insulating film and a corrugated plate are wound around a center electrode rod in a state of being laminated on each other, and a portion corresponding to a conductive path between the flat plate and the corrugated plate is provided. A preheated exhaust gas purifying metal carrier comprising a honeycomb structure joined at a brazing portion in which a strongly reduced metal oxide is dispersed and deposited, and an outer cylinder into which the honeycomb structure is inserted. 8. A flat plate having at least one surface coated with an insulating film and a corrugated plate are laminated on each other, wound around a center electrode rod having an extraction electrode, and provided on a conductive path between the flat plate and the corrugated plate. In a corresponding portion, a bonding material made of a strong reducing metal and a brazing material is disposed in a state where the strong reducing metal is in contact with the insulating film to form a honeycomb structure. The honeycomb structure is inserted into an outer cylinder to form a metal. Producing a carrier; and then performing a brazing process by heating the metal carrier in a non-oxidizing atmosphere, comprising the steps of: