JPH06146006A - Ferrite stainless steel material and its manufacture - Google Patents

Abstract

PURPOSE:To provide a ferrite stainless steel material which has basic characteristics and advantages of ferrite stainless steel with superior acid resistance as they are and is superior in electric conductivity at high temperatures. CONSTITUTION:An oxide layer is formed by a low-temperature plasma treatment on the surface of a steel plate containing 10-35% Cr and then the oxide layer is coated with a conductive oxide. Consequently, the steel material which has the small coefficient of thermal expansion and good consistency with ceramic is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a ferritic stainless steel having excellent oxidation resistance and electrical conductivity in a high temperature environment of, for example, 400 ° C. or more and having good compatibility with materials having a small coefficient of thermal expansion such as ceramics. Steel and its manufacturing method.

[0002]

2. Description of the Related Art Due to environmental problems including depletion of petroleum resources and air pollution in the 21st century, fuel cells that can use coal reformed gas as a next-generation power supply source have come into the limelight. There are various types of fuel cells, such as phosphoric acid type, molten carbonate type, and solid electrolyte type, depending on the electrolyte that generates electromotive force.
The operating temperature is also different.

Molten carbonate type, whose operating temperature is 650 ° C., 10
For both solid electrolyte type, which has a temperature of 00 ° C, reduction of fuel cell manufacturing cost and longevity are extremely important development issues for future practical use, and inexpensive and high-performance metal materials are required. ing. In particular, in the solid electrolyte type that can be said to be developed including the fuel cell structure, the constituent members such as the interconnector and the corrugated support layer, which are being studied in the laboratory, may be extremely expensive ceramics having electrical conductivity. Therefore, there is a strong demand for the development of an inexpensive high-performance metal material that can be used instead.

In the case of applying Fe-Cr ferritic stainless steel which does not contain a large amount of Ni as a constituent member such as an interconnector or a corrugated support layer of such a solid oxide fuel cell, the production is Although it is easy and extremely advantageous in terms of cost, it is necessary to impart performance that is different from conventional ferritic stainless steels in securing oxidation resistance and electrical conductivity at high temperatures.

By the way, relatively inexpensive materials are used for members used at higher temperatures than before, such as automobile exhaust manifolds, automobile exhaust gas reforming catalyst carriers, heat exchanger members, heating furnace members, and combustion members for heating equipment. As an example, there is ferritic stainless steel.

For example, in an exhaust manifold for automobiles,
12% Cr-based stainless steel such as SUH409, 17% Cr containing Nb and Cu
The ferritic stainless steel, or 19% Cr ferritic stainless steel of the same type is used. Also,
As an automobile exhaust gas reforming catalyst carrier, Ca or REM
A 20% Cr-5% Al-based ferritic stainless steel foil with added is used. 2.5% Si on the combustion parts of the stove
It is a well-known fact that 18% Cr-based ferritic stainless steel, which is contained, is often used.

Generally, in order to secure the oxidation resistance of Fe-Cr ferritic stainless steel at high temperature, 12% or more of Cr is added and 0.5% or more of Si or Al is added. Due to the addition of these alloying elements, SiO ₂ , Al ₂ O ₃ or Cr ₂ O _{3 is} applied to the steel surface during use in a high temperature oxidizing atmosphere.
The main oxide scale is generated, and further progress of oxidation is significantly suppressed.

Further, REM addition of Y, La, etc. is carried out for the purpose of fixing sulfide in steel as sulfide more stable than MnS. By adding more than 0.001% of these elements, preferably about 0.008%, local abnormal oxidation around the surface-exposed sulfide is suppressed, and the adhesion of oxide scale is improved, resulting in oxidation resistance. Is strengthened.

As described above, regarding the oxidation resistance, it is possible to improve the oxidation resistance to some extent by adding an appropriate amount of an oxidation resistance improving element such as Al or Si to the steel.
At that time, the oxide scale formed on the steel surface remarkably lowers the electrical conductivity at high temperature, and therefore it is necessary to devise a method for ensuring electrical conductivity at high temperature. Especially 1000
Al ₂ O ₃ is the most desirable for improving the oxidation resistance under conditions exceeding ℃
The film is an insulating oxide, and 10 ^-6 S / cm at around 1000 ° C
It has only moderate conductivity. On the other hand, Cr ₂ O _3, which is a P-type semiconductor and has a relatively good electric conductivity at 1000 ° C. of about 2 × 10 ⁻³ S / cm, has a fast scale growth rate and a constant scale thickness at a certain time. It is much thicker than Al ₂ O ₃ and may peel off. Therefore, in the case of Cr ₂ O ₃ oxide scale, it is necessary to increase the oxidation resistance and not to impair the conductivity.

Further, when considering use as a constituent member of a fuel cell, it is easily expected that the electrolyte will be damaged if the difference in thermal expansion from the ceramics constituting the electrolyte is large. The coefficient of thermal expansion of Fe-Cr ferritic stainless steel at around 1000 ° C is about 13 × 10 ^-6 / ° C, and that of Fe-Cr-Al ferritic stainless steel is about 15 × 10 ^-6 / ° C. ^Yes, it is larger than 10 × 10 ^-6 / ° C of the ceramics that make up the electrolyte, and may cause damage to the battery body. Desirably, the coefficient of thermal expansion is about the same as that of the ceramic constituting the electrolyte.

Now, in the ferritic stainless steel containing the above-mentioned oxidation resistance improving element, if the electrical conductivity at high temperature can be secured without impairing the basic characteristics, practicality and benefits In terms of sex, extremely large profits are expected.

[0012]

An object of the present invention is to provide a ferritic stainless steel material having the basic characteristics and advantages of a ferritic stainless steel excellent in oxidation resistance as they are, and having excellent electric conductivity at high temperature. And to provide its manufacturing method.

[0013]

Means for Solving the Problems The present inventors have conducted studies for the purpose of developing a material having excellent oxidation resistance and good electric conductivity at high temperatures, and have obtained the following findings.

When Cr, Al, Si, etc. are added to the ferritic stainless steel as alloying elements for improving the oxidation resistance, it can be used at 900 ° C. or higher from the viewpoint of the high temperature oxidation progress rate to some extent. The electrical conductivity at high temperature decreases with the growth of. In particular, when applied above 1000 ° C, it is most effective to add 3% or more of Al from the viewpoint of securing oxidation resistance.
Since the Al ₂ O ₃ film is formed, the electrical conductivity is significantly reduced.

When ferritic stainless steel with high Al content is applied to a portion such as an interconnector of a solid oxide fuel cell, the electric resistance becomes high and the cell characteristics may be greatly deteriorated with time. It is possible, to some extent, to improve the electrical conductivity by changing the oxide scale composition during use by optimizing the components in the steel, but in that case, the oxide scale produced by the environment to which the material is exposed More practical than changing.

Therefore, based on the above findings and consideration, the inventors of the present invention studied the improvement of oxidation resistance and the improvement of electrical conductivity at high temperature by various methods, and obtained the following findings. The present invention has been reached.

(1) Conventionally, in an interconnector for a fuel cell, an extremely expensive conductive ceramic having an oxidation resistance, a good electric conductivity, and a thermal expansion similar to that of a conductive ceramic constituting an electrolyte is used. It is used. Therefore, if inexpensive ferritic stainless steel can be applied, it is extremely promising as an alternative material.

(2) The ferritic stainless steel containing 10% or more of Cr can be applied for a long time without deteriorating the excellent oxidation resistance even in the temperature range exceeding 850 ° C and 950 ° C. It is promising as an interconnector material for fuel cells.

(3) Oxygen reaches the surface of the steel material in a high temperature oxidizing atmosphere by coating the surface of the steel material having good oxidation resistance at high temperature with a conductive oxide by a method such as vapor deposition or plasma spraying. Is slowed down, the oxidation resistance is further excellent, and good electrical conductivity is obtained.

(4) Prior to the coating treatment with the conductive oxide, a low temperature plasma treatment is carried out in a plasma atmosphere to form an oxide layer mainly containing Cr or Al oxide containing Cr in the outermost layer. Can be made. By providing a coating of a conductive oxide on the oxide layer thus produced, it is possible to further improve the oxidation resistance and also improve the adhesion of the vapor-deposited or plasma sprayed film.

Here, the present invention is such that Cr: 10 to 35% by weight.
It is an oxidation resistant ferritic stainless steel material which is excellent in electrical conductivity in a high temperature oxidizing atmosphere, characterized by containing a conductive oxide on the surface.

From another aspect, the present invention also provides, in weight percent,
Cr: An oxide layer is formed on the surface of a steel sheet containing 10 to 35% by low-temperature plasma treatment, and then a conductive oxide is coated on the oxide layer to form an electric field in a high-temperature oxidizing atmosphere. This is a method for producing an oxidation resistant ferritic stainless steel material having excellent conductivity.

According to a preferred embodiment of the present invention, a dew point temperature of -15 to -60 is further provided immediately after coating the conductive oxide.
You may perform the process hold | maintained at the temperature of 400-1200 degreeC for 1 second or more in the non-oxidizing atmosphere which is ℃. In addition, the above-mentioned "ferritic stainless steel material" refers to a general member made of ferritic stainless steel, and specific examples thereof include a plate material, a bar material, a pipe material, and a foil material.

[0024]

Next, the reason why the present invention is limited to the above range will be described. Cr: The subject of the present invention is the ferritic stainless steel to be treated, that is, the base material, Cr: 10 to 35%
There is no particular limitation as long as it contains That is, ferritic stainless steel was first selected as an inexpensive material, and its composition was used to form an oxide layer mainly composed of Cr oxide containing Cr or Al on the surface by low temperature plasma treatment performed as desired. The ratio is limited to 10-35%.

Therefore, Cr is a basic element necessary to obtain oxidation resistance at high temperature together with Al. In the present invention, the lower limit is 10% and the upper limit is 35%. This is 400
10 to produce Cr ₂ O ₃ -based oxide scales above ℃
This is because Cr of more than% is required. In addition, addition of more than 35% does not not only improve the oxidation resistance but also makes it particularly sensitive to σ embrittlement and 475 ° C embrittlement, which adversely affects the formability and workability of the plate. Is 35%.

Conductive oxide: The conductive oxide used as the coating material in the present invention has excellent oxidation resistance and electrical conductivity even in a high temperature oxidizing atmosphere as found in, for example, a solid oxide fuel cell. If it is not particularly limited as long as it is, according to its preferred embodiment, both are oxygen ion conductive oxides or mixed conductive oxides, in the present invention YSZ, LaCrO ₃ , LaCoO ₃ , LaMnO ₃ , La _{1 -x} Sr _x C
It is possible to use rO ₃ , La _1-x Sr _x MnO ₃ , La (CrCo) O ₃ , La _1-x Mg _x CrO _3, a mixture thereof, and a complex oxide.

Next, some explanation will be made on these conductive oxides used in the present invention. YSZ is a conductive ceramic in which low-valent oxide Y ₂ O ₃ is dissolved in ZrO ₂ having a fluorite structure so that fluorite cubic crystals can exist stably from high temperature to room temperature. This fluorite type solid solution shows that oxygen ions are not the closest packing, and that the substitutional solid solution range with alkaline earth or rare earth atoms is wide and the vacancy concentration at the oxygen atom position is high and the oxygen ion conductivity is large. .

On the other hand, the oxide represented by ABO ₃ is an oxide called a perovskite type oxide and exhibits mixed ion conductivity due to the movement of oxygen ions and electrons or holes. The coating method is preferably vapor deposition or plasma spraying, but any coating pyrolysis method may be used as long as it can coat the above-mentioned conductive oxide in the present invention. Therefore, the coating method used in the present invention is not particularly limited, but preferred embodiments of the vapor deposition method and the plasma spraying method will be described below.

The vapor deposition method is already known per se,
Although the treatment operation may be a conventional one, it is a conventional method, but it is necessary to optimize the alloying components and the oxygen potential of the atmosphere for each treatment condition so as to obtain an appropriate oxide composition.
As the thermal spraying method, those already known per se may be used. Plasma spraying under reduced pressure is desirable from the viewpoint of the denseness of the sprayed film, but the impact of the powder colliding with the base material during film formation is large, causing mechanical stress, and destroying the powder crystal structure. Leading to. Therefore, in the preferred embodiment of the present invention, plasma spraying under atmospheric pressure was used.

In the case of thermal spraying, the blasting treatment before the coating treatment is extremely effective in reducing the residual stress to reduce the grain size and improve the adhesion of the coating material to the base material.
This process is performed as needed. Prior to the coating of the oxide layer by such vapor deposition or thermal spraying method, low temperature plasma treatment may be performed as a kind of preliminary treatment. The vapor deposition layer, the thickness of the thermal spray layer and the like may be appropriately determined according to the purpose and are not particularly limited, but preferably the vapor deposition layer is 10 μm or less, and the thermal spray layer is 10 μm or less.
It should be 0 μm or less.

This low-temperature plasma treatment means, for example, performing ion bombardment treatment by applying a bias voltage of 0 to -500 V in a state where ferritic stainless steel is preheated to room temperature or higher than room temperature and 450 ° C. or less. The preheating temperature is set to 450 ° C or lower at which high temperature oxidation due to thermal diffusion becomes remarkable. The bias voltage is 0 to -500V. When the bias voltage is too large, the degree to which the atoms turned into plasma hit the surface becomes strong and the low-temperature plasma treatment effect decreases.
In addition, when a small amount of air or oxygen is introduced into the chamber during the treatment, there is a behavior that a specific element is concentrated and oxidized on the surface of the steel sheet during the low temperature plasma treatment. The oxide film composed of a specific element is effective in improving the oxidation resistance and the adhesiveness of the sprayed film, and therefore is performed as necessary.

The heat treatment after coating with the conductive oxide is carried out, if necessary, in a non-oxidizing atmosphere having a dew point temperature of -15 to -60 ° C.
It is carried out by holding at a temperature of 400 to 1200 ° C for 1 second or more. The treatment temperature is set to 400 to 1200 ° C because thermal diffusion does not occur below 400 ° C, and above 1200 ° C, the ferritic stainless steel that is the subject of the treatment of the present invention is fragile due to coarsening of grains. This is because the susceptibility and grain boundary stress sensitivity increase or a low melting point compound is produced.

The atmosphere in the furnace is extremely important for carrying out such an annealing treatment. The dew point is − in a non-oxidizing atmosphere or a decompressed atmosphere mainly composed of Ar, N ₂ , H _2, etc.
It is preferably maintained at 15 to -60 ° C. As described above, the composition of the ferritic stainless steel to which the present invention is applied is not particularly limited as long as Cr is 10 to 35%, but from a practical point of view, ferrite having the following composition ratio as described below is used. System stainless steel can be applied.

% By weight, C: 0.0001 to 0.030%, N: 0.0
001 to 0.030%, S: 0.0001 to 0.0020%, Cr: 10.00 to 3
5.00%, Al: 0.001 to 2.0%, Si: 0.01 to 6.0%, Mn: 0.
01 to 1.00%, P: 0.03% or less, Ti, Nb, 1 or 2
Species are 4 times or more of the total amount of C + N and 1.0% or less, and rare earth elements (REM) such as Ce and La, or 1 of Y and Ca if necessary.
0.20% or less of two or more species, and if necessary, M
o: 0.01-5.0% In addition, the steel contains 0.8% or less of Cu and Ni respectively, and the balance Fe and unavoidable impurities.

Further, in order to generate an oxide containing Al as a main component, ferritic stainless steel having the following composition ratio can be applied.

% By weight, C: 0.0001 to 0.050%, N: 0.0
001 to 0.010%, S: 0.0001 to 0.0020%, Cr: 10.00 to 3
5.00%, Al: 2.00 to 6.00%, Si: 0.01 to 6.00%, Mn: 0.
01 to 1.00%, P: 0.03% or less, Ti, Nb, 1 or 2
The total amount of C + N is 4 times or more and 1.0% or less, and if necessary, rare earth elements such as Ce and La, or one or more of Y and Ca is 0.20% or less, and if necessary, Mo: 0.01
~ 5.0% Others, containing 0.8% or less of Cu and Ni in steel, balance Fe and unavoidable impurities.

Although the present invention is not limited to such a steel composition, the reason why the steel composition is limited as described above will be described as a preferred example. C: C is an element that significantly reduces the toughness at room temperature, and when applied at high temperatures or in the heat-affected zone of the weld, it forms Cr ₂₃ C ₆ type carbides, and the effect of improving the oxidation resistance of Cr Has the effect of significantly reducing In addition, since it causes scale peeling, a lower value is preferable and the upper limit was made 0.03%. The lower limit is practically set to 0.0001%.

Al: Al is required to be 2.0% or more in order to form a uniform scale when forming an oxide mainly composed of Al (oxide having the highest content ratio of metallic Al in all oxides). is there. However, if it is added in excess of 6.0%, the toughness at room temperature will be significantly reduced, so the upper limit is made 6.0%. However, when an oxide mainly composed of Cr such as Cr ₂ O ₃ or CrFe ₂ O ₄ (oxide having the highest content of metallic Cr in all oxides) is produced, the content is limited to 0.001 to 2.0%.

Si: Si is a deoxidizing element, and acts as an element for improving the oxidation resistance when an oxide mainly containing Cr is formed. Al
When the main oxide is formed, the upper limit is set to 6.0% because the effect of Si on the improvement of oxidation resistance becomes insignificant and the toughness decreases.

N: N, like C, is an element that significantly reduces toughness at room temperature. Further, by forming a nitride by combining with Cr and Al in steel, there is an adverse effect that Cr and Al reduce the oxidation resistance at high temperature. The upper limit is 0.03%. For the purpose of reducing the adverse effects of C and N in steel, Ti and Nb stabilizing elements having a stronger affinity for C and N than Cr or Al are added. In order to improve the toughness at room temperature and the oxidation resistance at high temperature, there is a desirable amount of addition. In order to fix C and N in steel, Ti or Nb which is 4 times or more that of C + N (%) in steel is required. In addition, excessive addition of Ti and Nb also causes a decrease in toughness, so the upper limit is 1.00 with Ti + Nb (%).
%.

S: S has an upper limit of 0.002% and is fixed by adding a rare earth element such as Ce, La, Y or the like, which forms a more stable sulfide at a temperature higher than Mn, or Ca, if necessary. Turn into. For the purpose of enhancing these effects, the O concentration in steel is preferably low. This is because these additional elements tend to form oxides, are consumed as oxides before they function as S-fixing elements in steel, and the effective amount decreases. The lower the S + O (%) value in steel, the better,
A lower S + O (%) value is preferable, but S + O (%) ≤ 0.00
8%, more preferably S + O (%) ≦ 0.005% is required.

Mo: Mo may be added to secure strength at high temperature or to secure corrosion resistance. However, the upper limit is set to 5.0% due to the problem of reduced toughness. Mn: Mn may be added to secure strength at high temperatures. It is desirable that the content is about 0.01 to 1.00%.

P: P is not positively added. In principle, it is an impurity. Contains 0.03% or less. La, Ce, Y, Ca: As described above, these are S in steel.
It is an immobilizing element. Although it has a strong affinity with O in steel and is also consumed as an oxide, excessive addition adversely affects the oxidation resistance due to the formation of coarse oxide, so the total amount is 0.20%.
Add as needed within the following ranges.

Cu, Ni: Cu and Ni in the steel sometimes improve the corrosion resistance of the base material. May be contained at 0.8% or less, which has no particular adverse effect. Next, the effects of the present invention will be further described with reference to specific examples.

[0045]

【Example】

(Example 1) Steel Nos. 1 to 13 having the compositions shown in Table 1 are melted in a vacuum melting furnace and cast, hot-rolled and cold-rolled to a plate thickness of 1 mm. The various steel plates thus produced were used as vapor deposition or thermal spray substrates, degreased and washed with an organic solvent, and then coated with the conductive oxide in the amounts shown in Table 2 by vapor deposition or thermal spray.

The vapor deposition was carried out using an electron beam method at a vacuum degree of 1 × 10 ⁻³ to 10 ⁻⁵ torr in a vacuum chamber. The oxygen potential depends on the partial pressure adjustment in the vacuum chamber and / or the residual water content.
The thermal spraying was performed by a reduced pressure plasma system with an arc voltage of 25 V and an arc current of 400 A. The working gas is Ar or Ar.
And a mixed gas of N ₂ + H ₂ was used.

The steel plate thus obtained has a thickness of 1 mm
Cut out a test piece measuring 20 mm in width and 25 mm in length and 1000 ° C in the atmosphere.
An oxidation test by continuous heating was conducted. Table 1 of the present invention steel were coated with LaCrO ₃ by vapor deposition of the steel types No.1~11 and comparative steel No.12, oxidation aging extenders at 1000 ° C. of 13 (mg / cm ²⁾
Is shown in FIG.

Among the steels of the present invention, No. 1 and No. 6 coating methods, coating materials and coating layer thickness treatment conditions, and 1000 ° C. × 1000 in air
Table 2 shows the results of the change in the amount increased after hr oxidation. In the oxidation test, the oxidation resistance was evaluated based on the magnitude of the increase in the amount of oxidation after the oxidation including scale peeling.

FIG. 2 shows LaCrO ₃ , LaSrCrO ₃ and La formed by vapor deposition.
Steel No. 1 of the present invention which has been subjected to various coating treatments such as CoO ₃ and Al ₂ O _3.
2 is a graph showing the results of electric resistance after the oxidation in the atmosphere at 1000 ° C. for 1000 hours. The measurement was performed in the thickness direction of the steel sheet, and the result was converted to sheet resistance (Ω · cm ² ).

From the change over time in the amount of oxidation increase shown in FIG. 1, it can be seen that each steel type having the proper chemical composition shown in the present invention is excellent in oxidation resistance. Further, as shown in Table 2, those coated with a conductive oxide have better oxidation resistance than steel without coating. From the result of resistance measurement shown in FIG. 2, it can be seen that the conductivity is extremely improved by the coating treatment with the conductive oxide.

(Example 2) Steel No. of the present invention used in Example 1
The ferritic stainless steel sheets 1 and 6 were subjected to low temperature plasma treatment, heat treatment after oxide coating, or blast treatment under the conditions shown in Table 3. An oxidation test was conducted on the steel sheet of Steel No. 1 of the present invention thus obtained. FIG. 3 is a graph showing the results of the change in the amount of oxidation increase with time when heated at 1000 ° C. in the atmosphere. It can be seen that the low temperature plasma treatment improves the oxidation resistance. This is because under proper low-temperature plasma conditions, Cr-based oxide or Al-containing Cr-based oxide is densely formed on the surface of the steel sheet.

Furthermore, by performing heat treatment after coating, the oxidation resistance is further improved. It is considered that the oxide scale becomes dense due to the high temperature heat treatment accompanied by thermal diffusion.
In particular, since the oxide coated by plasma spraying under atmospheric pressure has many pores and facilitates the ingress of oxygen, it is extremely effective to seal the pores by heat treatment.

Next, the results of examining the thermal expansion of the invention steel No. 1 in a high temperature atmosphere are shown in the graph of FIG. In this example, LaCoO ₃ was sprayed, LaCrO ₃ was deposited, and LaMnO ₃ was deposited. According to the present invention, by coating a ferritic stainless steel with a conductive ceramic such as LaCrO ₃ or LaMnO ₃ , in the temperature range of 500 to 1000 ° C., for example, LaMnO ₃ , YS
It has a coefficient of expansion close to that of Z, and has good compatibility with ceramics.

[0054]

[Table 1]

[0055]

[Table 2]

[0056]

[Table 3]

[0057]

As described above, according to the present invention, by coating a ferritic stainless steel, which is a relatively inexpensive material, with a conductive oxide, high temperature can be achieved without sacrificing oxidation resistance. The electric conductivity is secured, and the steel material thus obtained has good compatibility with ceramics having a small coefficient of thermal expansion, and therefore exhibits usefulness as a constituent member of a fuel cell.

[Brief description of drawings]

FIG. 1 is a graph showing the oxidation resistance of the materials obtained in the examples.

FIG. 2 is a graph showing the electric conductivity of a material coated with each conductive oxide.

FIG. 3 is a graph showing the effects of low temperature plasma treatment and heat treatment after coating in Examples.

FIG. 4 is a graph showing the coefficient of thermal expansion of a material that has been subjected to a low temperature plasma treatment and a heat treatment after coating in an example.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location C23C 8/36 7516-4K 28/04 H01M 8/02 B 8821-4K Z 8821-4K

Claims (3)

[Claims] 1. An oxidation resistant ferritic stainless steel material having excellent electrical conductivity in a high temperature oxidizing atmosphere, characterized in that it contains Cr: 10 to 35% by weight and has a surface coated with a conductive oxide. 2. An oxide layer is formed on a surface of a steel sheet containing Cr: 10 to 35% by weight by low temperature plasma treatment, and then a conductive oxide is coated on the oxide layer. A method for producing an oxidation resistant ferritic stainless steel material with excellent electrical conductivity in a high temperature oxidizing atmosphere. 3. After coating with the conductive oxide, the conductive oxide is further applied in a non-oxidizing atmosphere having a dew point temperature of −15 to −60 ° C.
The method for producing an oxidation resistant ferritic stainless steel material having excellent electrical conductivity in a high temperature oxidizing atmosphere according to claim 2, characterized in that the temperature is maintained at 0 to 1200 ° C for 1 second or more.