阅读说明：本技术 合金部件、电池堆以及电池堆装置 (Alloy member, cell stack, and cell stack device ) 是由 田中裕己 中村俊之 大森诚 于 2019-09-03 设计创作，主要内容包括：分流器(200)的顶板(201)具备：基材(210)、多个埋设部(213)、以及涂膜(211)。基材(210)由含有铬的合金材料构成,且在表面(210a)具有多个凹部(210b)。各埋设部(213)由陶瓷材料构成,且配置于各凹部(210b)内。涂膜(211)覆盖表面(210a),且与各埋设部(213)连接。基材(210)的厚度方向上的截面处的多个埋设部(212)构成为：将与厚度方向垂直的面方向上的各埋设部(213)中的埋设于各凹部(210b)的部分的中点连结得到的线段的实际长度(L1)的平均值比将线段的起点与终点连结的直线长度(L2)的平均值长。实际长度(L1)的平均值为直线长度(L2)的平均值的1.10倍以上。(A top plate (201) of a flow divider (200) is provided with: a base material (210), a plurality of embedded parts (213), and a coating film (211). The base (210) is made of an alloy material containing chromium, and has a plurality of recesses (210b) on the surface (210 a). Each embedded portion (213) is made of a ceramic material and is disposed in each recess (210 b). The coating film (211) covers the surface (210a) and is connected to each embedded portion (213). A plurality of embedded parts (212) at the cross section of the base material (210) in the thickness direction are configured in such a manner that: the average value of the actual lengths (L1) of line segments obtained by connecting the midpoints of the portions embedded in the recesses (210b) in each embedded portion (213) in the plane direction perpendicular to the thickness direction is longer than the average value of the linear lengths (L2) connecting the start point and the end point of the line segment. The average value of the actual length (L1) is 1.10 times or more the average value of the straight length (L2).)

1. An alloy member, comprising:

a base material made of an alloy material containing chromium and having a plurality of recesses on a surface thereof;

a plurality of embedded portions each made of a ceramic material and respectively disposed in the plurality of concave portions; and

a coating film covering at least a part of the surface of the base material and connected to the plurality of buried portions,

the plurality of embedded portions at a cross section of the base material in the thickness direction are configured such that: an average value of actual lengths of line segments connecting midpoints of portions embedded in the respective recesses in the respective embedded portions in a plane direction perpendicular to the thickness direction is longer than an average value of straight line lengths connecting start points and end points of the line segments,

the average value of the actual length is 1.10 times or more the average value of the straight line length.

2. The alloy component of claim 1,

the length of the joint between the embedded parts and the coating film is 0.1 μm or more.

3. A stack of cells, wherein,

the disclosed device is provided with: an electrochemical cell and the alloy member according to claim 1 or 2,

the alloy member is a current collecting member electrically connected to the electrochemical cell.

4. A cell stack device, wherein,

the disclosed device is provided with: an electrochemical cell and the alloy member according to claim 1 or 2,

the alloy member is a current divider that supports a base end portion of the electrochemical cell.

5. An alloy member, comprising:

a base material made of an alloy material containing chromium and having a plurality of recesses on a surface thereof;

a plurality of embedded portions each made of a ceramic material and respectively disposed in the plurality of concave portions; and

a coating film covering at least a part of the surface of the base material and connected to the plurality of buried portions,

the plurality of embedded portions at a cross section of the base material in the thickness direction are configured such that: an average value of actual lengths of line segments connecting midpoints of portions embedded in the respective recesses in the respective embedded portions in a plane direction perpendicular to the thickness direction is longer than an average value of straight line lengths connecting start points and end points of the line segments,

the plurality of embedded portions are each made of a material different from the coating film.

6. An alloy member, comprising:

a base material made of an alloy material containing chromium and having a plurality of recesses on a surface thereof;

a plurality of embedded portions each formed of an oxide of an element having a lower equilibrium oxygen pressure than that of chromium and disposed in each of the plurality of recessed portions; and

a coating film covering at least a part of the surface of the base material and connected to the plurality of buried portions,

the plurality of embedded portions at a cross section of the base material in the thickness direction are configured such that: an average value of actual lengths of line segments connecting midpoints of portions embedded in the respective recesses in the respective embedded portions in a plane direction perpendicular to the thickness direction is longer than an average value of straight line lengths connecting start points and end points of the line segments,

the plurality of buried portions respectively satisfy: the average content of elements having a lower equilibrium oxygen pressure than that of chromium is 0.05 or more in terms of cation ratio.

Technical Field

The invention relates to an alloy member, a cell stack, and a cell stack device.

Background

Conventionally, a cell stack device is known, which includes: a cell stack in which a plurality of fuel cells, which are one of electrochemical cells, are electrically connected by a current collecting member; and a flow divider that supports each fuel cell (see patent documents 1 and 2). The current collecting member and the current divider use an alloy member.

In the shunt of patent document 1, a coating film is provided to cover the surface of a base material so as to suppress volatilization of Cr (chromium) from the base material made of stainless steel.

The current collecting member of patent document 2 is provided with a coating film covering the surface of a base material so as to suppress volatilization of Cr from the base material made of an Fe — Cr alloy, an Ni — Cr alloy, or the like.

In addition, in patent document 2, a part of the chromium oxide film in contact with the substrate in the coating film enters the recessed portion on the surface of the substrate, and thereby the coating film can be prevented from peeling from the substrate.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2015-035418

Patent document 2: international publication No. 2013/172451

Disclosure of Invention

However, in the current collecting member of patent document 2, the coating film may be peeled off from the base material during operation of the cell stack device.

The invention aims to provide an alloy member, a cell stack and a cell stack device capable of inhibiting the peeling of a coating film.

The alloy member according to the present invention includes: a base material made of an alloy material containing chromium and having a plurality of recesses on a surface thereof; a plurality of embedded portions each made of a ceramic material and respectively disposed in the plurality of recesses; and a coating film that covers at least a part of the surface of the base material and is connected to the plurality of buried portions. The plurality of embedded portions at the cross section of the base material in the thickness direction are configured such that: the average value of the actual lengths of the line segments connecting the midpoints of the portions embedded in the recesses in the embedded portions in the plane direction perpendicular to the thickness direction is longer than the average value of the linear lengths connecting the start point and the end point of the line segment. The average value of the actual length is 1.10 times or more the average value of the straight line length.

Effects of the invention

According to the present invention, an alloy member, a cell stack, and a cell stack device capable of suppressing the peeling of a coating film can be provided.

Drawings

Fig. 1 is a perspective view of a cell stack device.

Fig. 2 is a perspective view of the flow diverter.

Fig. 3 is a cross-sectional view of a cell stack device.

Fig. 4 is a perspective view of a fuel cell unit.

Fig. 5 is a Q-Q sectional view of fig. 4.

Fig. 6 is a cross-sectional view P-P of fig. 2.

Fig. 7 is an enlarged view of the area a of fig. 6.

Fig. 8 is an explanatory view of a manufacturing method of the shunt.

Fig. 9 is an explanatory view of a manufacturing method of the shunt.

Fig. 10 is an explanatory view of a manufacturing method of the shunt.

Fig. 11 is an explanatory view of a manufacturing method of the shunt.

Fig. 12 is an explanatory view of a manufacturing method of the shunt.

Fig. 13 is a sectional view showing the structure of the coating film according to modification 6.

Fig. 14 is a sectional view showing the structure of the coating film according to modification 7.

Detailed Description

An embodiment of a cell stack device according to the present embodiment will be described with reference to the drawings.

[ cell stack device 100]

Fig. 1 is a perspective view of a cell stack device 100. The cell stack device 100 includes: a shunt 200, and a cell stack 250.

[ shunt 200]

Fig. 2 is a perspective view of the flow diverter 200. The shunt 200 is an example of an "alloy member".

The shunt 200 is constituted: fuel gas (e.g., hydrogen) is distributed to each fuel cell 300. The flow divider 200 is hollow and has an internal space. The fuel gas is supplied to the inner space of the flow divider 200 through the introduction pipe 204.

The shunt 200 has: a top plate 201 and a container 202. The top plate 201 is formed in a flat plate shape. The container 202 is formed in a cup shape. The top plate 201 is configured to: the upper opening of the container 202 is closed.

The top plate 201 is joined to the container 202 by the joining material 103 (not shown in fig. 2, see fig. 6). Examples of the bonding material 103 include: crystallized glass, amorphous glass, a brazing material, ceramics, and the like. In the present embodiment, the crystallized glass is: the ratio of the volume occupied by the crystalline phase to the entire volume (degree of crystallization)) The glass is 60% or more, and the ratio of the volume occupied by the amorphous phase and impurities to the whole volume is less than 40%. Examples of the crystallized glass include: SiO 2₂－B₂O₃SiO 2₂Of the CaO series, or SiO₂-MgO system.

A plurality of insertion holes 203 are formed in the top plate 201. The insertion holes 203 are arranged in parallel in the arrangement direction (z-axis direction) of the fuel cells 300. The insertion holes 203 are arranged with a space therebetween. Each insertion hole 203 communicates with the internal space and the outside of the flow divider 200.

Hereinafter, the detailed configuration of the shunt 200 will be described.

[ cell stack 250]

Fig. 3 is a sectional view of the cell stack device 100. The cell stack 250 has: a plurality of fuel cell single cells 300, and a plurality of current collecting members 301.

Each fuel cell 300 extends from the flow divider 200. Specifically, each fuel cell 300 extends upward (along the x-axis direction) from the top plate 201 of the flow divider 200. That is, the longitudinal direction (x-axis direction) of each fuel cell 300 extends upward. The length of each fuel cell 300 in the longitudinal direction (x-axis direction) is about 100 to 300mm, but the length is not limited thereto.

The base end portion of each fuel cell 300 is inserted into the insertion hole 203 of the flow divider 200. Each fuel cell 300 is fixed to the insertion hole 203 by the bonding material 101. The fuel cell 300 is fixed to the flow divider 200 by the bonding material 101 in a state of being inserted into the insertion hole 203. The bonding material 101 is filled in the gap between the fuel cell 300 and the insertion hole 203. Examples of the bonding material 101 include: crystallized glass, amorphous glass, a brazing material, ceramics, and the like.

Each fuel cell 300 is formed in a plate shape extending in the longitudinal direction (x-axis direction) and the width direction (y-axis direction). The fuel cells 300 are arranged with an interval therebetween along the arrangement direction (z-axis direction). The interval between the adjacent 2 fuel cell units 300 is not particularly limited, and may be about 1 to 5 mm.

Each fuel cell 300 has a gas flow path 11 inside. During operation of the cell stack device 100, fuel gas (hydrogen, etc.) is supplied from the flow divider 200 to each gas channel 11, and oxidant gas (air, etc.) is supplied to the outer periphery of each fuel cell 300.

The adjacent 2 fuel cell single cells 300 are electrically connected by the current collecting member 301. The current collecting member 301 is joined to the base end side of each of the adjacent 2 fuel cell units 300 via the joining material 102. The bonding material 102 is, for example, selected from (Mn, Co)₃O₄、(La，Sr)MnO₃And (La, Sr) (Co, Fe) O₃And the like.

[ Fuel cell Single cell 300]

Fig. 4 is a perspective view of the fuel cell unit 300. Fig. 5 is a Q-Q sectional view of fig. 4.

The fuel cell 300 has: a support substrate 10, and a plurality of power generation element units 20.

(supporting base plate 10)

The support substrate 10 has a plurality of gas flow channels 11 extending in the longitudinal direction (x-axis direction) of the support substrate 10 inside. Each gas flow path 11 extends from the base end side toward the tip end side of the support substrate 10. The gas flow channels 11 extend substantially parallel to each other.

As shown in fig. 5, the support substrate 10 has a plurality of first concave portions 12. In the present embodiment, the first recesses 12 are formed on both main surfaces of the support substrate 10, but may be formed on only one main surface. The first concave portions 12 are arranged at intervals in the longitudinal direction of the support substrate 10.

The support substrate 10 is made of a porous material having no electron conductivity. The support substrate 10 may be made of, for example, CSZ (calcium oxide stabilized zirconia). Alternatively, the support substrate 10 may be made of NiO (nickel oxide) and YSZ (8YSZ) (yttria-stabilized zirconia), or NiO (nickel oxide) and Y₂O₃(yttrium oxide), and optionally MgO (magnesium oxide) and MgAl₂O₄(magnesium aluminate spinel). The porosity of the support substrate 10 is, for example, about 20 to 60%.

(Power generating element section 20)

Each power generation element unit 20 is supported by the support substrate 10. In the present embodiment, the power generating element units 20 are formed on both main surfaces of the support substrate 10, but may be formed on only one main surface. The power generating element units 20 are disposed at intervals in the longitudinal direction of the support substrate 10. That is, the fuel cell 300 according to the present embodiment is a so-called lateral stripe type fuel cell. The power generation element portions 20 adjacent in the longitudinal direction are electrically connected to each other by the interconnector 31.

The power generation element unit 20 includes: a fuel electrode 4, an electrolyte 5, an air electrode 6, and a reaction preventing film 7.

The fuel electrode 4 is a sintered body made of a porous material having electron conductivity. The fuel electrode 4 has: a fuel electrode collector 41 and a fuel electrode active portion 42.

The fuel electrode collector 41 is disposed in the first recess 12. Specifically, the fuel electrode collector 41 is filled in the first recess 12 and has the same outer shape as the first recess 12. The fuel electrode collector 41 includes: a second recess 411 and a third recess 412. The fuel electrode active portion 42 is disposed in the second recess 411. In addition, the interconnector 31 is disposed in the third recess 412.

The fuel electrode collector 41 has electron conductivity. Preferably, the fuel electrode current collector 41 has higher electron conductivity than the fuel electrode active portion 42. The fuel electrode current collector 41 may or may not have oxygen ion conductivity.

The fuel electrode current collector portion 41 may be made of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria-stabilized zirconia). Alternatively, the fuel electrode current collecting portion 41 may be formed of NiO (nickel oxide) and Y₂O₃(yttria) or NiO (nickel oxide) or CSZ (calcium oxide stabilized zirconia). The thickness of the fuel electrode collector 41 and the depth of the first recess 12 are about 50 to 500 μm.

The fuel electrode active portion 42 has oxygen ion conductivity and also has electron conductivity. The content ratio of the substance having oxygen ion conductivity in the fuel electrode active portion 42 is greater than the content ratio of the substance having oxygen ion conductivity in the fuel electrode current collector portion 41. In detail, the volume ratio of the substance having oxygen ion conductivity to the entire volume excluding the pore portion in the fuel electrode active portion 42 is larger than the volume ratio of the substance having oxygen ion conductivity to the entire volume excluding the pore portion in the fuel electrode current collector portion 41.

The fuel electrode active portion 42 may be made of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria-stabilized zirconia). Alternatively, the fuel electrode active portion 42 may be composed of NiO (nickel oxide) and GDC (gadolinium-doped cerium oxide). The thickness of the fuel electrode active part 42 is 5 to 30 μm.

The electrolyte 5 is disposed so as to cover the fuel electrode 4. In detail, the electrolyte 5 extends in the length direction from one interconnector 31 to an adjacent interconnector 31. That is, the electrolyte 5 and the interconnectors 31 are alternately and continuously arranged in the longitudinal direction (x-axis direction) of the support substrate 10. The electrolyte 5 is constituted by: covering both main surfaces of the support substrate 10.

The electrolyte 5 is a fired body made of a dense material having ion conductivity but not electron conductivity. The electrolyte 5 may be composed of, for example, YSZ (8YSZ) (yttria-stabilized zirconia). Alternatively, the electrolyte 5 may be composed of LSGM (lanthanum gallate). The thickness of the electrolyte 5 is, for example, about 3 to 50 μm.

The air electrode 6 is a sintered body made of a porous material having electron conductivity. The air electrode 6 is disposed on the opposite side of the fuel electrode 4 with respect to the electrolyte 5. The air electrode 6 has: an air electrode active portion 61 and an air electrode current collecting portion 62.

The air electrode active portion 61 is disposed on the reaction preventing film 7. The air electrode active portion 61 has oxygen ion conductivity and also has electron conductivity. The content of the substance having oxygen ion conductivity in the air electrode active portion 61 is greater than the content of the substance having oxygen ion conductivity in the air electrode current collecting portion 62. Specifically, the volume ratio of the substance having oxygen ion conductivity in the air electrode active portion 61 to the entire volume excluding the pore portion is larger than the volume ratio of the substance having oxygen ion conductivity in the air electrode current collecting portion 62 to the entire volume excluding the pore portion.

The air electrode active portion 61 may be made of, for example, LSCF ═ (La, Sr) (Co, Fe) O₃(lanthanum strontium cobalt ferrite). Alternatively, the air electrode active portion 61 may be formed of LSF ═ (La, Sr) FeO₃(lanthanum strontium ferrite), LNF ═ La (Ni, Fe) O₃(lanthanum nickel ferrite), or LSC ═ La, Sr) CoO₃(lanthanum strontium cobaltates) and the like. The air electrode active portion 61 may be composed of 2 layers of a first layer (inner layer) composed of LSCF and a second layer (outer layer) composed of LSC. The thickness of the air electrode active part 61 is, for example, 10 to 100 μm.

The air electrode current collecting portion 62 is disposed on the air electrode active portion 61. The air electrode current collecting portion 62 extends from the air electrode active portion 61 toward the adjacent power generating element portion. The fuel electrode collector portion 41 and the air electrode collector portion 62 extend from the power generation region to the opposite side from each other. The power generation region is: the fuel electrode active portion 42, the electrolyte 5, and the air electrode active portion 61 overlap.

The air electrode current collecting portion 62 is a sintered body made of a porous material having electron conductivity. Preferably, the air electrode current collecting portion 62 has higher electron conductivity than the air electrode active portion 61. The air electrode current collecting portion 62 may or may not have oxygen ion conductivity.

The air electrode collector 62 may be made of, for example, LSCF ═ (La, Sr) (Co, Fe) O₃(lanthanum strontium cobalt ferrite). Alternatively, the air electrode collector 62 may be formed of LSC ═ co (La, Sr)₃(lanthanum strontium cobaltate). Alternatively, the air electrode collector 62 may be made of Ag (silver) or Ag — Pd (silver palladium alloy). The thickness of the air electrode collector 62 is, for example, about 50 to 500 μm.

The reaction-preventing film 7 is a sintered body made of a dense material. The reaction preventing film 7 is disposed between the electrolyte 5 and the air electrode active portion 61. The reaction preventing film 7 is provided so as to suppress the occurrence of a phenomenon in which YSZ in the electrolyte 5 reacts with Sr in the air electrode 6 to form a reaction layer having a large resistance at the interface between the electrolyte 5 and the air electrode 6.

The reaction prevention film 7 is composed of a material containing cerium oxide containing a rare earth element. Preventing reactionThe membrane 7 may be made of, for example, GDC ═ Ce (Gd) O₂(gadolinium-doped ceria). The thickness of the reaction-preventing film 7 is, for example, about 3 to 50 μm.

The interconnector 31 is constituted by: the power generation element portions 20 adjacent in the longitudinal direction (x-axis direction) of the support substrate 10 are electrically connected. Specifically, the air electrode current collecting portion 62 of one power generation element portion 20 extends toward the other power generation element portion 20. The fuel electrode collector 41 of the other power generation element portion 20 extends toward the one power generation element portion 20. The interconnector 31 electrically connects the air electrode collector portion 62 of one power generation element portion 20 and the fuel electrode collector portion 41 of the other power generation element portion 20. The interconnector 31 is disposed in the third recess 412 of the fuel electrode collector 41. In detail, the interconnector 31 is embedded in the third recess 412.

The interconnector 31 is a fired body made of a dense material having electron conductivity. The interconnector 31 may be made of, for example, LaCrO₃(lanthanum chromate). Alternatively, the interconnector 31 may be made of (Sr, La) TiO₃(strontium titanate). The thickness of the interconnector 31 is, for example, 10 to 100 μm.

[ detailed construction of the shunt 200]

Next, the detailed configuration of the shunt 200 will be described with reference to the drawings. Fig. 6 is a cross-sectional view P-P of fig. 2. Fig. 7 is an enlarged view of the area a of fig. 6.

The top plate 201 and the container 202 are joined by the joining material 103. An internal space S1 to which the fuel gas is supplied is formed between the top plate 201 and the container 202.

The top plate 201 has: a base material 210, a coating film 211, and an embedded portion 213. The container 202 has a base 220, a coating film 221, and an embedded portion 223. The coating film 211 includes: a chromium oxide film 211a and a coating film 211 b. The coating film 221 includes: a chromium oxide film 221a and a coating film 221 b.

The top plate 201 and the container 202 are examples of "alloy members". The substrate 210 and the substrate 220 are examples of "substrates", respectively. The coating film 211 and the coating film 221 are examples of "coating films", respectively. The embedded portion 213 and the embedded portion 223 are examples of "embedded portions", respectively.

Since the structure of the container 202 is the same as that of the top plate 201, the structure of the top plate 201 will be described below with reference to fig. 7.

The base material 210 is formed in a plate shape. The base 210 may be flat or curved. The thickness of the substrate 210 is not particularly limited, and may be, for example, 0.5 to 4.0 mm.

The base material 210 is made of an alloy material containing Cr (chromium). As such a metal material, Fe-Cr alloy steel (stainless steel or the like), Ni-Cr alloy steel or the like can be used. The content of Cr in the base material 210 is not particularly limited, and may be 4 to 30 mass%.

The base material 210 may contain Ti (titanium) or Al (aluminum). The content ratio of Ti in the base material 210 is not particularly limited, and may be 0.01 to 1.0 at.%. The content of Al in the base material 210 is not particularly limited, and may be 0.01 to 0.4 at.%. The substrate 210 may be TiO₂(titanium dioxide) contains Ti, and may be Al₂O₃The form (alumina) contains Al.

The base material 210 has: a surface 210a, and a plurality of recesses 210 b. The surface 210a is the surface of the outer side of the substrate 210. The base 210 is joined to the coating film 211 on the surface 210 a. In fig. 7, the front surface 210a is formed in a substantially planar shape, but may be formed with fine irregularities or may be entirely or partially curved or bent.

Each recess 210b is formed in the surface 210 a. Each recess 210b extends from the surface 210a toward the inside of the base material 210. Each embedded portion 213 described later is embedded in each concave portion 210 b.

The number of the concave portions 210b is not particularly limited, and is preferably widely distributed on the surface 210 a. The interval between the concave portions 210b is not particularly limited, and is particularly preferably arranged at a uniform interval. This allows the anchor effect by each embedded portion 213 to be exhibited uniformly over the entire coating film 211, and thus, the coating film 211 can be particularly prevented from peeling off from the base material 210.

At least a part of the plurality of concave portions 210b has a cross-sectional shape that is entirely or partially curved or bent. The cross-sectional shape of such a recess 210b is not a linear shape, but a shape at least partially deformed by flexure. The deepest portion of the recess 210b may be acute-angled, obtuse-angled, or rounded. In fig. 7, the overall curved wedge-shaped recess 210b (the right side of fig. 7) and the lower half curved wedge-shaped recess 210b (the left side of fig. 7) are shown. The cross-sectional shape of a part of the plurality of concave portions 210b may be linear as a whole.

The coating film 211 covers at least a part of the substrate 210 and is connected to each embedded portion 213. In the present embodiment, the coating film 211 includes: a chromium oxide film 211a and a coating film 211 b.

A chromium oxide film 211a is formed on the surface 210a of the substrate 210. The chromium oxide film 211a covers at least a part of the surface 210a of the substrate 210. The chromium oxide film 211a is connected to each embedded portion 213. The chromium oxide film 211a is formed to cover each embedded portion 213. The chromium oxide film 211a is connected to each embedded portion 213. The thickness of the chromium oxide film 211a is not particularly limited, and may be 0.5 to 10 μm.

The coating film 211b covers at least a part of the chromium oxide film 211 a. Specifically, the coating film 211b covers at least a part of the region of the chromium oxide film 211a that is in contact with the oxidizing gas during operation of the cell stack device 100. Preferably, the coating film 211b covers the entire surface of the region of the chromium oxide film 211a that is in contact with the oxidizing gas. The thickness of the coating film 211b is not particularly limited, and may be, for example, 3 to 200 μm.

The coating film 211b suppresses volatilization of Cr from the substrate 210 to the outside. This can suppress deterioration of the electrode (air electrode 6 in the present embodiment) of each fuel cell 300 due to Cr poisoning.

The coating film 211b is made of a ceramic material. The ceramic material constituting the coated film 211b may be selected from suitable materials depending on the application site. When the alloy member according to the present invention is applied to the shunt 200 as in the present embodiment, the coating film 211b is required to have insulation properties, and therefore, examples of the ceramic material include: alumina, silica, zirconia, crystallized glass, and the like. On the other hand, when the alloy member according to the present invention is applied to the current collecting member 301, the coating film 211b is required to have conductivity, and thus, examples of the ceramic material include a perovskite-type composite oxide containing La and Sr and a spinel-type composite oxide composed of a transition metal such as Mn, Co, Ni, Fe, and Cu. However, the coating 211b may be one that can suppress the volatilization of Cr, and the material constituting the coating 211b is not limited to the ceramic material.

Buried portion 213 is disposed in recess 210b of substrate 210. Buried portion 213 is connected to chromium oxide film 211a in the vicinity of the opening of concave portion 210 b. In this embodiment, the chromium oxide film 211a is interposed between each embedded portion 213 and the coated film 211b, and therefore each embedded portion 213 is connected to the chromium oxide film 211 a. However, when the chromium oxide film 211a is not interposed between each embedded portion 213 and the coating film 211b, each embedded portion 213 is connected to the coating film 211 b.

The average actual length of the plurality of buried portions 213 is longer than the average straight length of the plurality of buried portions 213 in the cross section of the base material 210 in the thickness direction. This means that: at least a portion of embedded portion 213 is bent or flexed wholly or partially, so that at least a portion of embedded portion 213 is flexed and deformed. Therefore, since the anchor effect of embedded portion 213 to substrate 210 can be increased, coating film 211 can be prevented from peeling off from substrate 210.

The average actual length of the plurality of buried portions 213 is: the average value of the actual length L1 of each buried portion 213. The actual length L1 is: as shown in fig. 7, the length of a line segment connecting midpoints of portions of the embedded portion 213 that are embedded in the concave portion 210b in a plane direction perpendicular to the thickness direction. Actual length L1 represents the total length of buried portion 213 in the extending direction.

The average actual length of the embedded portions 213 is obtained by randomly selecting 20 embedded portions 213 from an image obtained by enlarging the cross section of the substrate 210 by 1000 times to 20000 times using an FE-SEM (field emission scanning electron microscope), and arithmetically averaging the actual lengths L1 of the 20 embedded portions 213 to obtain the average actual length of the embedded portions 213. When 20 buried portions 213 are not observed in 1 cross section, 20 buried portions 213 may be selected from among the plurality of cross sections. However, the embedded portion 213 having the actual length L1 of less than 0.1 μm has a slight anchor effect and contributes little to the effect of suppressing the peeling of the coating film 211, and therefore, this is excluded from the calculation of the average actual length of the embedded portion 213.

The average linear length of the plurality of buried portions 213 is: the average of linear lengths L2 of embedded portions 213. The straight length L2 is: as shown in fig. 7, the length of a straight line connecting the start point and the end point of a line segment of a predetermined actual length L1. The straight line length L2 represents the shortest distance between both ends of buried portion 213.

The average linear length of the plurality of embedded portions 213 is obtained by arithmetically averaging the linear lengths L2 of the 20 embedded portions 213 selected for obtaining the average actual length, thereby obtaining the average linear length of the plurality of embedded portions 213.

Note that, if embedded portion 213 is formed entirely in a linear shape, actual length L1 is substantially the same as linear length L2, but if at least a portion of embedded portion 213 is deformed due to flexure as in the present embodiment, actual length L1 is longer than linear length L2. Actual length L1 and linear length L2 may be different in each embedded portion 213 as shown in fig. 7, or may be the same between embedded portions 213.

The ratio of the average actual length to the average straight length (average actual length/average straight length) is not particularly limited, and is preferably 1.10 or more. This can sufficiently increase the anchor effect of embedded portion 213 with respect to substrate 210, and thus can further suppress peeling of coating film 211 from substrate 210. The ratio of the average actual length of embedded portion 213 to the average straight length (average actual length/average straight length) is more preferably 1.2 or more, and particularly preferably 1.3 or more.

The average actual length is not particularly limited, and may be, for example, 0.5 μm or more and 600 μm or less. The average linear length is not particularly limited, and may be, for example, 0.4 μm or more and 550 μm or less.

The average vertical length of embedded portion 213 in the cross section of base material 210 in the thickness direction is not particularly limited, and may be, for example, 0.4 μm or more and 500 μm or less. The average vertical length is: the average vertical length L3 of each buried portion 213. The vertical length L3 is: as shown in fig. 7, the total length of the portion embedded in the concave portion 210b in the embedded portion 213 in the thickness direction perpendicular to the surface 210a of the base 210. Vertical length L3 may be different for each buried portion 213 as shown in fig. 7, or may be the same between buried portions 213.

In addition, the average bonding width of the plurality of buried portions 213 and the chromium oxide film 211a at the cross section of the base 210 in the thickness direction is preferably 0.1 μm or more. This improves the bonding strength between each embedded portion 213 and the coating film 211, and thus prevents the embedded portion 213 itself from coming off the coating film 211. As a result, the coating film 211 can be further inhibited from peeling off from the substrate 210.

The average joint width of the plurality of buried portions 213 is: the average value of the joint width W1 of each embedded portion 213. The engagement width W1 is: the total length of the wiring of the embedded portion 213 and the coating film 211 at the cross section in the thickness direction of the base material 210. The line connecting the embedded portion 213 and the coating film 211 may be curved, wavy, or the like, in addition to being linear.

The average joint width of the plurality of embedded portions 213 is obtained by arithmetically averaging the joint widths W1 of the 20 embedded portions 213 selected for obtaining the average vertical length described above, thereby obtaining the average joint width of the plurality of embedded portions 213.

The upper limit of the bonding width W1 is not particularly limited, and may be, for example, 100 μm or less.

The ratio of the average joining width to the average actual length (average joining width/average actual length) is not particularly limited, and is preferably 0.5 or less. This allows embedded portion 213 to protrude steeply, and thus, the anchoring force of embedded portion 213 to base material 210 can be further increased.

Buried portion 213 is made of a ceramic material. Examples of the ceramic material constituting embedded portion 213 include: cr (chromium) component₂O₃(chromium oxide) and Al₂O₃(aluminum oxide), TiO₂(titanium dioxide), CaO (calcium oxide), SiO₂(silica), MnO (manganese oxide), MnCr₂O₄(manganese chromium spinel), and the like, but are not limited thereto.

The ceramic material constituting the embedded portion 213 is preferably an oxide of an element having a lower equilibrium oxygen pressure than that of Cr (chromium) (hereinafter referred to as "low equilibrium oxygen pressure element"). Since the low equilibrium oxygen pressure element has a higher affinity for oxygen than Cr and is easily oxidized, oxygen permeating through the coating film 211 preferentially enters the embedded portion 213 during operation of the cell stack device 100, and thus oxidation of the substrate 210 surrounding the embedded portion 213 can be suppressed. This can maintain the form of embedded portion 213, and thus can obtain the anchor effect of embedded portion 213 over a long period of time. As a result, the coating film 211 can be inhibited from peeling off from the substrate 210 for a long period of time.

Examples of the low equilibrium oxygen pressure element include: al (aluminum), Ti (titanium), Ca (calcium), Si (silicon), Mn (manganese), and the like, and examples of oxides thereof include: al (Al)₂O₃、TiO₂、CaO、SiO₂、MnO、MnCr₂O₄And the like, but are not limited thereto.

The buried portion 213 may contain only oxides of 1 kind of low equilibrium oxygen tension element, or may contain oxides of 2 or more kinds of low equilibrium oxygen tension elements. For example, embedded portion 213 may be made of Al₂O₃May be formed of Al₂O₃And TiO₂May also consist of TiO₂MnO and MnCr₂O₄The mixture of (a).

When the molar ratio of each element to the sum of all the constituent elements excluding oxygen is defined as a cation ratio, the average content of the low equilibrium oxygen tension element in the plurality of buried portions 213 is preferably 0.05 or more in terms of the cation ratio. This can further suppress oxidation of the base material 210 surrounding the embedded portion 213, and thus can obtain the anchor effect by the embedded portion 213 for a longer period of time.

The upper limit of the average content of the low equilibrium oxygen tension element in the plurality of buried portions 213 is not particularly limited, and is preferably larger.

The average content of the low equilibrium oxygen tension element in the plurality of buried portions 213 is determined by the following method. First, the content of the low equilibrium oxygen tension element at 10 points, which is obtained by dividing the actual length L1 into eleven points, was measured for each of the 20 buried portions 213 selected for the purpose of obtaining the average vertical length described above. Next, for each buried portion 213, the maximum value is selected from among the content ratios measured at 10 points. Then, the average content of the low equilibrium oxygen tension element is determined by arithmetically averaging 20 maximum values selected for the 20 buried portions 213.

Preferably, buried portion 213 is in contact with at least a part of the inner surface of recess 210 b. Particularly preferably, the embedded portion 213 is filled in the entire recess 210b so as to be in contact with substantially the entire inner surface of the recess 210 b.

The number of buried portions 213 is not particularly limited, and in the cross-sectional view of the base material 210, 10 or more buried portions 213 are preferably observed per 10mm length of the front surface 210a, and more preferably 20 or more buried portions 213 are observed per 10mm length. This enables the anchor effect by the embedded portion 213 to be exhibited in a wide range, and thus, the coating film 211 can be further inhibited from peeling off from the substrate 210.

[ method for manufacturing shunt 200]

A method of manufacturing the shunt 200 will be described with reference to the drawings. Since the method of manufacturing the container 202 is the same as the method of manufacturing the top plate 201, the method of manufacturing the top plate 201 will be described below.

First, as shown in fig. 8, a plurality of concave portions 210b are formed on the surface 210a of the base 210. For example, the concave portion 210b can be formed with high efficiency by using shot blasting, sand blasting, or wet blasting. At this time, the depth and width of the recess 210b are adjusted by adjusting the particle size of the polishing agent. Thus, the average actual length, the average straight length, the average vertical length, and the average joint width of the plurality of buried portions 213 to be formed later can be adjusted. In addition, after the concave portion 210b is formed, the surface is flattened by using a roller so that the concave portion 210b is wholly or partially bent or flexed. This allows at least a part of the buried portion 213 to be formed later to be deformed.

Next, as shown in fig. 9, ethyl cellulose and terpineol are added to the oxide of the low equilibrium oxygen tension element to obtain a paste for embedded portion, and the paste for embedded portion is applied to the surface 210a of the substrate 210, thereby filling the paste for embedded portion into the concave portion 210 b.

Next, as shown in fig. 10, the paste for a buried portion applied to the surface 210a of the substrate 210 is removed using, for example, a squeegee.

Next, as shown in fig. 11, the base 210 is heat-treated in the atmosphere (800 to 900 ℃ for 1 to 20 hours), whereby the embedded portion paste filled in the concave portion 210b is cured to form the embedded portion 213, and a chromium oxide film 211a covering the embedded portion 213 is formed.

Then, as shown in FIG. 12, a coating paste containing a ceramic material for coating is applied to the chromium oxide film 211a and heat-treated (800 to 900 ℃ C., 1 to 5 hours) to form a coating film 211 b.

(other embodiments)

The present invention is not limited to the above embodiments, and various modifications and changes can be made without departing from the scope of the present invention.

[ modification 1]

In the above embodiment, the alloy member according to the present invention is applied to the shunt 200, but the present invention is not limited thereto. The alloy member according to the present invention can be used as a member constituting a part of the cell stack device 100 and the cell stack 250. For example, the alloy member according to the present invention can be applied to the current collecting member 301 electrically connected to the fuel cell 300.

[ modification 2]

In the above embodiment, the cell stack 250 has the fuel cells of the striped type, but may have the fuel cells of the so-called striped type. The vertically striped fuel cell includes: the fuel cell includes a conductive support substrate, a power generation section (including a fuel electrode, a solid electrolyte layer, and an air electrode) disposed on one main surface of the support substrate, and an interconnector disposed on the other main surface of the support substrate.

[ modification 3]

Although the embedded portion 213 is disposed in the recessed portion 210b in the above embodiment, when the base material 210 has a plurality of recessed portions 210b, there may be a recessed portion 210b in which the embedded portion 213 is not disposed.

[ modification 4]

Although the embedded portion 213 is connected to the coating film 211 in the above embodiment, if there are a plurality of embedded portions 213, there may be an embedded portion 212 that is not connected to the coating film 211.

[ modification 5]

In the above embodiment, the case where the alloy member according to the present invention is applied to a stack of a fuel cell as an example of an electrochemical cell has been described, but the alloy member according to the present invention can be applied to a stack of an electrochemical cell including an electrolysis cell in which hydrogen and oxygen are generated by steam.

[ modification 6]

In the above embodiment, the coating film 211 includes the chromium oxide film 211a and the coating film 211b, but may include at least the coating film 211 b. For example, as shown in fig. 13, the coating film 211 may substantially include only the coated film 211 b. The actual length L1, the linear length L2, and the joint width W1 of each embedded portion 213 are as described in the above embodiments. However, since each buried portion 213 is connected to the coating film 211b, the joint width W1 is the total length of the wiring between the buried portion 213 and the coating film 211 b. Even in the configuration shown in fig. 13, peeling of the coating film 211 from the base material 210 can be suppressed for a long period of time by making the average actual length of each embedded portion 213 containing an oxide of a low equilibrium oxygen tension element longer than the average straight length. The coating film 211 including only the coating film 211b can be formed by embedding the embedding portion paste in the concave portion 210b, applying the coating film paste, and performing heat treatment, thereby forming the coating film 211 including only the coating film 211 b.

[ modification 7]

In the above embodiment, each embedded portion 213 is connected to the chromium oxide film 211a in the coating film 211, but each embedded portion 213 may be connected to the coating film 211b in the coating film 211 as shown in fig. 14. In this case, a part of each embedded portion 213 protrudes out of the recessed portion 210b of the base 210, and the remaining part of each embedded portion 213 is embedded in the recessed portion 210b of the base 210. The portion of each embedded portion 213 that is embedded in the concave portion 210b exerts an anchoring effect on the base material 210. Therefore, as shown in fig. 14, the actual length L1 of each embedded portion 213 is the total length in the extending direction of the portion embedded in the recess 210b, and the linear length L2 of each embedded portion 213 is the shortest distance between both ends of the portion embedded in the recess 210 b. Although not shown in fig. 14, since each buried portion 213 is connected to both the chromium oxide film 211a and the coating film 211b, the joint width W1 is the total length of the wiring between the buried portion 213 and the chromium oxide film 211a and the wiring between the buried portion 213 and the coating film 211 b. Even in the configuration shown in fig. 14, peeling of the coating film 211 from the base material 210 can be suppressed for a long period of time by making the average actual length of each embedded portion 213 containing an oxide of a low equilibrium oxygen tension element longer than the average straight length. In order to connect each embedded portion 213 to the coating film 211b in the coating film 211, a process may be performed in which after embedding the embedded portion paste in the concave portion 210b, the coating film paste is applied to the substrate 210 and heat treatment is performed, thereby forming the coating film 211b and depositing the chromium oxide film 211a between the substrate 210 and the coating film 211 b.

Examples

Examples of the alloy member according to the present invention will be described below, but the present invention is not limited to the examples described below.

(production of examples 1 to 19 and comparative examples 1 to 4)

An alloy member having the configuration shown in fig. 7 was produced as follows.

First, a plate member made of SUS430 was prepared as a base material.

Next, the surface of the base material is subjected to sandblasting, thereby forming a plurality of concave portions on the surface of the base material. At this time, the depth and width of the recess were adjusted by adjusting the particle size of the abrasive. Then, the surface is flattened by a roller, whereby each concave portion is wholly or partially bent or flexed. Accordingly, as shown in table 1, the average actual length, the average linear length, and the average joint width of the plurality of embedded portions formed later were adjusted for each of examples 1 to 19 and comparative examples 1 to 4.

Next, ethyl cellulose and terpineol were added to the ceramic material powder shown in table 1, thereby preparing a paste for a buried portion.

Next, the prepared paste for a buried portion is applied to the surface of the substrate, thereby filling the respective recesses with the paste for a buried portion, and then, the excess paste for a buried portion on the surface is removed by a squeegee.

Next, ethyl cellulose and terpineol were added to the chromium oxide powder, thereby preparing a chromium oxide film paste.

Next, the prepared paste for a chromium oxide film is applied to a substrate, and heat treatment is performed in an atmospheric atmosphere (800 to 900 ℃, 1 to 5 hours), whereby the paste for a buried portion filled in the recessed portion is cured to form a buried portion, and a chromium oxide film connected to the buried portion is formed.

Next, ethyl cellulose and terpineol were added to the ceramic material powder for coating shown in table 1, thereby preparing a paste for coating.

Then, the prepared paste for coating was applied on a chromium oxide film and heat-treated (850 ℃ C., 2 hours), thereby forming a coating film.

(examples 20 to 23 and comparative examples 5 to 6)

Although the coating films including the chromium oxide film and the coating film were formed in examples 1 to 20 and comparative examples 1 to 4, the coating films including only the coating film were formed in examples 20 to 23 and comparative examples 5 to 6 as shown in fig. 13.

Specifically, after filling the embedded portion paste into the recessed portion of the substrate, the coating film paste is applied to the substrate and heat-treated (850 ℃ C., 2 hours), whereby the embedded portion is formed by curing and the coating film connected to the embedded portion is formed.

(average actual length of buried part, average straight line length, and average joining width)

The average actual length, the average linear length, and the average joint width of the embedded part were measured for examples 1 to 23 and comparative examples 1 to 6.

First, 20 embedded parts were randomly selected from an image obtained by enlarging the cross section of the base material 1000 to 20000 times by FE-SEM, and the actual length L1, the linear length L2, and the bonding width W1 of each embedded part were measured. Then, the average actual length was obtained by arithmetically averaging the 20 actual lengths L1, the average straight length was obtained by arithmetically averaging the 20 straight lengths L2, and the average joining width was obtained by arithmetically averaging the 20 joining widths W1.

(peeling observation)

For examples 1 to 23 and comparative examples 1 to 6, peeling observation was performed by simulating an actual use environment.

First, the produced alloy member was put into an electric furnace, and heating and cooling cycles were repeated 50 times in an atmospheric atmosphere. The heating and cooling cycle includes: a heating procedure of heating to 850 ℃ at a heating speed of 300 ℃/h and preserving heat at 850 ℃ for 30min, and a cooling procedure of cooling to 100 ℃ at a cooling speed of 300 ℃/h and preserving heat at 100 ℃ for 30 min.

Then, the appearance of the alloy member was visually observed to confirm the presence or absence of visually identifiable peeling, and the surface of the alloy member was observed with an electron microscope to confirm the presence or absence of microscopic peeling. In table 1, the case where only microscopic peeling was observed was evaluated as Δ, and the case where peeling in appearance was observed was evaluated as x. Further, the alloy member for which no separation was confirmed was subjected to the test described below.

Next, the alloy member in which no peeling was observed was held in a furnace heated to 850 ℃ for 1000 hours, and then, the cooling-heating cycle was repeated again 50 times. The cooling and heating cycle includes the cooling step and the heating step described above.

Then, the presence or absence of microscopic peeling was confirmed by observing the cross section of the alloy member with an electron microscope. In table 1, the case where no microscopic peeling was observed was evaluated as excellent, and the case where microscopic peeling was observed was evaluated as good.

TABLE 1

As shown in table 1, in examples 1 to 23 in which the average actual length of the embedded portion was made longer than the average straight line length, the peeling of the coating film was suppressed as compared with comparative examples 1 to 6 in which the average actual length of the embedded portion was made equal to the average straight line length. This is because: by bending and deforming at least a part of the embedded portion, the anchor effect is improved, and the adhesion of the coating film to the substrate can be improved.

In examples 1 to 17 in which the average bonding width of the embedded portion was set to 0.1 or more, the peeling of the coating film was further suppressed as compared with examples 18 to 19 in which the average bonding width was set to less than 0.1. Similarly, in examples 20 to 22 in which the average bonding width of the embedded portion was 0.1 or more, the peeling of the coating film was further suppressed as compared with example 23 in which the average bonding width was less than 0.1. This is because: by setting the average joining width to 0.1 or more, the joining strength between each embedded portion and the coating film is increased, and thereby, the embedded portion itself can be suppressed from being detached from the coating film.

In examples 1 to 9 in which the embedded part was formed of an oxide of a low equilibrium oxygen tension element having an equilibrium oxygen tension lower than that of Cr, the peeling of the coating film was further suppressed as compared with examples 10 to 19 in which the embedded part was formed of chromium oxide. Similarly, in examples 20 to 21 in which the embedded part was formed of an oxide of a low equilibrium oxygen tension element having an equilibrium oxygen tension lower than that of Cr, the peeling of the coating film was further suppressed as compared with examples 23 to 23 in which the embedded part was formed of chromium oxide. This is because: by further suppressing oxidation of the base material surrounding the embedded portion, the anchor effect by the embedded portion can be obtained for a longer period of time.

Description of the symbols

100 cell stack device

200 shunt

201 Top plate

210 base material

211 coating film

211a chromium oxide film

212b coating film

213 buried part

250 cell stack