KR101937924B1 - Coated steel plate for solid oxide fuel cell and method for manufacturing the same - Google Patents

Abstract

A coated steel sheet for a solid oxide fuel cell and a method for manufacturing the same. One embodiment of the present invention relates to a steel sheet for a solid oxide fuel cell (SOFC); And a coating layer made of a Cu-Mn alloy which is located on the surface of the steel sheet and contains 40 to 55% by weight of Cu and 45 to 60% by weight of Mn.

Description

TECHNICAL FIELD [0001] The present invention relates to a coated steel sheet for a solid oxide fuel cell,

One embodiment of the present invention relates to a coated steel sheet for a solid oxide fuel cell and a method of manufacturing the same. And more particularly to a coated steel sheet for a solid oxide fuel cell excellent in chrome poisoning resistance and a method of manufacturing the same.

Solid Oxide Fuel Cell (SOFC) is a fuel cell that operates at a high temperature of about 700 ° C, and is a metal separator. Although the material of the metal separator is specialized material, STS400 system is mainly used for general purpose.

In the STS400 system, corrosion-resistant Cr-Mn-Fe oxides are formed on the surface in a high-temperature oxidizing atmosphere, resulting in not only surface separation but also volatilization of hexavalent Cr (Cr ^{6 +} ). The volatilization of Cr is a phenomenon to be suppressed because it is deposited on the cathode constituting the SOFC cell to form an insulating second product or interfere with the three phase interface at which the reaction occurs. In addition, the oxide film of the STS400 material has a low conductivity, which increases the resistance of the stack and adversely affects the reliability of the stack due to the heat generated thereby.

In order to solve these problems, various protective coating materials and protective coating methods have been researched and developed, and researches are being conducted to develop new types of steel.

An embodiment of the present invention relates to a coating steel sheet for a solid oxide fuel cell capable of enhancing the longevity and performance of a solid oxide fuel cell (SOFC) by realizing high electrical conductivity and prevention of chromium volatilization, Method.

A coated steel sheet for a solid oxide fuel cell (SOFC) according to an embodiment of the present invention is a steel sheet for a solid oxide fuel cell (SOFC) and a Cu- Mn alloy.

The coating layer may be made of a Cu-Mn alloy containing 43 to 49% by weight of Cu and 51 to 57% by weight of Mn.

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The steel sheet for a solid oxide fuel cell (SOFC) may include ferrite, austenite, or a combination thereof.

The thickness of the coating layer may be 2 to 20 占 퐉.

The area specific resistance (ASR) of the coated steel sheet for a solid oxide fuel cell may be 0.1 to 18 mm? / Cm ² .

The coated steel sheet for a solid oxide fuel cell may have an area specific resistance (ASR) of 0.1 to 18 mm? / Cm ² after being left at 800 占 폚 for 5000 hours.

According to an embodiment of the present invention, there is provided a method for manufacturing a coated steel sheet for a solid oxide fuel cell (SOFC), comprising the steps of: preparing a steel sheet for a solid oxide fuel cell (SOFC), comprising 40 to 55% by weight of Cu and 45 to 60% % ≪ / RTI > of a Cu-Mn alloy.

The coating layer may be made of a Cu-Mn alloy containing 43 to 49% by weight of Cu and 51 to 57% by weight of Mn.

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The steel sheet for a solid oxide fuel cell (SOFC) may include ferrite, austenite, or a combination thereof.

The step of forming the coating layer may be performed by electroplating, electroless plating, physical vapor deposition (PVD), chemical vapor deposition (CVD), spray coating, or a combination thereof .

According to an embodiment of the present invention, there is provided a coated steel sheet for a solid oxide fuel cell capable of improving life span and performance of a solid oxide fuel cell (SOFC) by realizing high electrical conductivity and chromium volatilization prevention, A manufacturing method can be provided.

Also, according to one embodiment of the present invention, a coating steel sheet for a solid oxide fuel cell capable of realizing high electrical conductivity and chromium volatilization prevention by a combination of low-cost raw materials and a method of manufacturing the same can be provided.

Fig. 1 shows the result of sheet resistance measurement of the coated steel sheet for solid oxide fuel cell produced in Example 2 and Comparative Example 1 by the standing time.
Fig. 2 shows the result of measuring the sheet resistance of the coated steel sheet for a solid oxide fuel cell manufactured in Example 7 by the standing time.
FIG. 3 shows the results of the constant current performance evaluation of the 1-cell stack of the coated steel sheet for a solid oxide fuel cell manufactured in Example 2 and a steel sheet to which no coating was applied.
FIG. 4 is a result of evaluating the thermal cycle durability of a coated steel sheet for a solid oxide fuel cell manufactured in Example 2 and a steel sheet not coated with the same.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

Throughout the specification, when an element is referred to as " comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

To provide a coated steel sheet for a solid oxide fuel cell and a method of manufacturing the same, which can improve life span and performance of a solid oxide fuel cell (SOFC) by realizing high electrical conductivity and prevention of chromium volatilization Respectively.

Hereinafter, a coated steel sheet for a solid oxide fuel cell according to an embodiment of the present invention and a method of manufacturing the same will be described.

An embodiment of the present invention is a steel sheet for a solid oxide fuel cell (SOFC) and a solid oxide fuel cell comprising a coating layer composed of a Cu-Mn alloy located on the surface of a steel sheet and containing 40 to 55% by weight of Cu and the balance Mn A coated steel sheet for a battery is provided.

In one embodiment of the present invention, the Cu-Mn alloy on the metal is coated to convert into a spinel phase that is naturally electrically conductive during the operation of the solid oxide fuel cell.

First, in one embodiment of the present invention, a steel sheet for a solid oxide fuel cell (SOFC) For example, as a base material of a separator, a metal separator is used as such a separator, and a special material is available. However, the STS400 system is mainly used for general purpose.

However, in the STS400 system, corrosion-resistant Cr-Mn-Fe oxides are formed on the surface in a high-temperature oxidizing atmosphere, resulting in not only surface separation but also volatilization of hexavalent Cr (Cr ^{6 +} ). The volatilization of Cr is a phenomenon to be suppressed because it is deposited on the cathode constituting the SOFC cell to form an insulating second product or interfere with the three phase interface at which the reaction occurs. In addition, the oxide film of the STS400 material has a low conductivity, which increases the resistance of the stack and adversely affects the reliability of the stack due to the heat generated thereby.

In order to solve such a problem, a coating layer is formed on the steel sheet for a solid oxide fuel cell, thereby realizing high electrical conductivity and chromium volatilization prevention.

The coating layer according to an embodiment of the present invention is located on the surface of the above-mentioned steel sheet for a solid oxide fuel cell, and is made of a Cu-Mn alloy containing 40 to 55% by weight of Cu and the balance Mn. Coating a Cu-Mn alloy of the aforementioned composition in one embodiment of the invention, and when this alloy in the solid oxide fuel cell operation be oxidized to spinel, by smoothly forming the Cu-Mn spinel cubic Cu ^{2 +,} Cu ^{4 +} , Mn ^{2 +} to Mn ^{4 +} , and the electric conduction by hopping is excellent at the octahedral site where they are located.

When the Cu-Mn alloy contains too much or too much Cu, the CuO or Mn ₂ O ₃ oxide and the spinel phase coexist, and the electrical conductivity may be rapidly lowered. Therefore, it is possible to form a Cu-Mn alloy coating layer by controlling the content of Mn and Cu in the above-mentioned range. More specifically, it may contain 43 to 49% by weight of Cu and the balance of Mn.

The coating layer may be made of a Cu-Co-Mn alloy containing Co in addition to the above-mentioned Mn and Cu. When Co is additionally formed, Co ₃ O ₄ is located at the tetrahedral site of spinel when the spinel phase is formed, thereby stabilizing the spinel structure and rendering Cu and Mn well positioned in the octahedron do. Therefore, it helps to make a stable spinel structure. When it further contains Co, it can further contain 10 to 30% by weight of Co. If Co is included too little, it is difficult to expect an improvement effect due to the addition of Co. On the contrary, when Co is contained too much, Co occupies the Mn sites of the octahedron, and in such a case, Co occupies the Mn site, which is a multivalent element, which may cause a problem of lowering the electric conductivity by hopping. Therefore, Co can be further added to the above-mentioned range.

The thickness of the coating layer may be 2 to 20 占 퐉, more specifically 5 to 15 占 퐉. When the thickness of the coating layer is within the above range, the life of the coated steel sheet for the solid oxide fuel cell (SOFC) can be improved and the performance can be improved.

The coated steel sheet for a solid oxide fuel cell according to an embodiment of the present invention can improve the life span and performance of a solid oxide fuel cell (SOFC) by realizing high electrical conductivity and prevention of chromium volatilization. Specifically, the area specific resistance (ASR) of the coated steel sheet for a solid oxide fuel cell may be 0.1 to 18 mm? / Cm ² . Also, the coated steel sheet for a solid oxide fuel cell may have an Area Specific Resistance (ASR) of 0.1 to 18 mm? / Cm ² after being left at 800 占 폚 for 5000 hours.

Another embodiment of the present invention is a method for manufacturing a solid oxide fuel cell (SOFC), comprising the steps of preparing a steel sheet for a solid oxide fuel cell (SOFC) and forming a coating layer made of a Cu-Mn alloy containing 40 to 45 wt% The present invention also provides a method for producing a coated steel sheet for a solid oxide fuel cell.

The steel sheet for a solid oxide fuel cell (SOFC) and the coating layer are the same as those described above, so duplicate descriptions are omitted.

According to another embodiment of the present invention, the step of forming the coating layer on the surface of the steel sheet may be carried out by a method such as electrolytic plating, electroless plating, physical vapor deposition (PVD), chemical vapor deposition spray coating, or a combination thereof.

Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are only illustrative of the present invention and are not intended to limit the scope of the present invention.

Example

Example  One

Crofer 22 was prepared as a steel sheet for a solid oxide fuel cell (SOFC). A coating layer made of a Cu-Mn alloy containing 60 wt% of Mn and 40 wt% of Cu was formed on the steel sheet by electrolytic plating. The coating layer had a thickness of 10 mu m and an area of 100 cm < ^{2 &} gt ;.

Example  2

A coating layer made of a Cu-Mn alloy including 58 wt% of Mn and 42 wt% of Cu was formed in the same manner as in Example 1.

Example  3

A coating layer made of a Cu-Mn alloy including 56 wt% of Mn and 44 wt% of Cu was formed in the same manner as in Example 1.

Example  4

A coating layer made of a Cu-Mn alloy containing 53% by weight of Mn and 47% by weight of Cu was formed in the same manner as in Example 1.

Example  5

A coating layer made of a Cu-Mn alloy including 50 wt% of Mn and 50 wt% of Cu was formed in the same manner as in Example 1.

Example  6

A coating layer made of a Cu-Mn alloy including 25 wt% Mn and 55 wt% Cu was formed in the same manner as in Example 1.

Example  7

A coating layer made of a Cu-Co-Mn alloy containing 37 wt% of Mn, 9 wt% of Co, and 54 wt% of Cu was formed in the same manner as in Example 1.

Comparative Example  One

A coating layer made of a Cu-Mn alloy including 30 wt% of Mn and 70 wt% of Cu was formed in the same manner as in Example 1.

Comparative Example  2

A coating layer made of a Cu-Mn alloy containing 70 wt% of Mn and 30 wt% of Cu was formed in the same manner as in Example 1.

Experimental Example  One : Sheet resistance  Measure value

The degradation behavior of the 1-cell stack was evaluated for the steel sheets prepared in Examples 1 to 7 and Comparative Examples 1 and 2. Specifically, Area Specific Resistance (ASR) was measured at 800 ° C. The measurement of the sheet resistance was carried out by applying a current density of 1 A / cm ^{2 in} the atmosphere.

FIG. 1 shows the results of sheet resistance measurement of the coated steel sheet for solid oxide fuel cell manufactured in Example 2 and Comparative Example 1 by the dwell time.

In the case of Example 2, a consistent ASR value of about 3.0 mm? / Cm ² was exhibited up to about 6000 hours, whereas in Comparative Example 1, the ASR value increased sharply around 1500 hours.

FIG. 2 shows the result of measuring the sheet resistance of the coated steel sheet for a solid oxide fuel cell according to Example 7.

It can be confirmed that Example 7 also exhibits a constant ASR value up to about 5000 hours.

The steel sheets prepared in Examples 1 to 7 and Comparative Examples 1 and 2 were allowed to stand at 800 ° C for 1500 hours and for 5000 hours, and sheet resistance values were measured and are summarized in Table 1 below.

Coating layer Alloy component (% by weight) ASR value (mm Ω / cm ² ) Mn Cu Co Immediately After 1500 hours After 5000 hours Example 1 60 40 - 3.3 3.4 3.3 Example 2 58 42 - 3.0 3.0 2.9 Example 3 56 44 - 2.0 2.0 1.9 Example 4 53 47 - 1.0 0.9 0.9 Example 5 50 50 - 4.0 5.0 5.5 Example 6 45 55 - 4.5 6.0 7.0 Example 7 37 54 9 14.0 16.0 16.4 Comparative Example 1 30 70 - 5.8 7.7 10.2 Comparative Example 2 70 30 - 7 9 11

As shown in Table 1, it was confirmed that Examples 1 to 7 still had excellent ASR values after 1,500 hours and 5000 hours of storage. On the other hand, in Comparative Example 1 and Comparative Example 2, it was confirmed that the ASR value rapidly increased with time.

Experimental Example  2: Constant current performance evaluation

The static current performance of one cell was evaluated for the steel sheet prepared in Example 2 and the steel sheet to which no protective coating was applied. And a current density of 0.3 A / cm < ² > in an atmospheric environment. The results are shown in Fig.

The red line is the steel sheet prepared in Example 2, and the black line is the steel sheet not coated with the protective coating. As shown in FIG. 3, when the protective coating is applied, stable durability of 0% / 1,000 hr can be confirmed.

Experimental Example  3: Heat cycle  Durability evaluation

A four-cell stack using four sheets of 100 cm ² cells was formed on the steel sheet prepared in Example 2, and the heat cycle was performed 30 times between 150 and 700 ° C. The results are shown in FIG.

As shown in Fig. 4, excellent thermal cycle durability of 0 to 0.05% / heat cycle as a result of thermal cycle was also confirmed.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (12)

A steel sheet for a solid oxide fuel cell (SOFC); And
A coating layer disposed on the surface of the steel sheet and made of a Cu-Mn alloy containing 40 to 55 wt% of Cu and 45 to 60 wt% of Mn;
And a coating layer formed on the surface of the steel sheet. The method according to claim 1,
Wherein the coating layer comprises a Cu-Mn alloy containing 43 to 49 wt% of Cu and 51 to 57 wt% of Mn. delete The method according to claim 1,
Wherein the steel sheet for a solid oxide fuel cell (SOFC) comprises a ferrite-based, austenite-based, or a combination thereof. The method according to claim 1,
Wherein the coating layer has a thickness of 2 to 20 占 퐉. The method according to claim 1,
Wherein the coated steel sheet for a solid oxide fuel cell has an area specific resistance (ASR) of 0.1 to 18 mm? / Cm ² . The method according to claim 1,
Wherein the coated steel sheet for a solid oxide fuel cell has an Area Specific Resistance (ASR) of 0.1 to 18 mm? / Cm ² after being left at 800 占 폚 for 5000 hours. Preparing a steel sheet for a solid oxide fuel cell (SOFC); And
Forming a coating layer made of a Cu-Mn alloy containing 40 to 55 wt% of Cu and 45 to 60 wt% of Mn on the surface of the steel sheet;
Wherein the method comprises the steps of: preparing a coated steel sheet for a solid oxide fuel cell; 9. The method of claim 8,
Wherein the coating layer comprises a Cu-Mn alloy containing 43 to 49% by weight of Cu and 51 to 57% by weight of Mn. delete 9. The method of claim 8,
The steel sheet for a solid oxide fuel cell (SOFC)
A method of producing a coated steel sheet for a solid oxide fuel cell, comprising a ferrite system, an austenite system, or a combination thereof. 9. The method of claim 8,
Forming the coating layer,
A coating steel sheet for a solid oxide fuel cell, which is carried out by electroplating, electroless plating, physical vapor deposition (PVD), chemical vapor deposition (CVD), spray coating, Gt;

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