JP6435431B2 - Alloy member, cell stack and cell stack apparatus - Google Patents

Description

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

  2. Description of the Related Art Conventionally, a cell stack device is known that includes a cell stack in which a plurality of fuel cells are electrically connected by a current collecting member, and a manifold that supports each fuel cell (see Patent Documents 1 and 2). . An alloy member is used for the current collecting member and the manifold.

  In the manifold of Patent Document 1, a coating film that covers the surface of the base material is provided in order to suppress the 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 that covers the surface of the base material in order to suppress the volatilization of Cr from the base material composed of an Fe—Cr alloy or Ni—Cr alloy. It has been.

  Moreover, in patent document 2, when a part of chromium oxide film | membrane formed between a base material and a coating film enters into the recessed part of the base material surface, it can suppress that a coating film peels from a base material. It is said that.

Japanese Patent Laying-Open No. 2015-035418 International Publication No. 2013/172451

  However, in the current collecting member disclosed in Patent Document 2, during the operation of the cell stack apparatus, the oxidation of the base material surrounding the chromium oxide embedded in the concave portion proceeds, so that the chromium oxide grows greatly.

  As a result, the chromium oxide having a tapered shape before the start of operation becomes a rounded shape during the operation and the anchor effect is lowered, so that the coating film may be peeled off from the base material.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an alloy member, a cell stack, and a cell stack device that can suppress peeling of a coating film.

  The alloy member according to the present invention has a base having a concave portion on the surface and made of an alloy material containing chromium, an anchor portion disposed in the concave portion and containing an oxide containing manganese, and connected to the anchor portion. And a coating film covering at least a part of the chromium oxide film.

  ADVANTAGE OF THE INVENTION According to this invention, the alloy member, cell stack, and cell stack apparatus which can suppress peeling of a coating film can be provided.

Perspective view of cell stack device Manifold perspective view Cross section of cell stack device Perspective view of fuel cell QQ sectional view of FIG. PP sectional view of FIG. Enlarged view of region A in FIG. Explanatory drawing of manufacturing method of manifold Explanatory drawing of manufacturing method of manifold Explanatory drawing of manufacturing method of manifold Explanatory drawing of manufacturing method of manifold Explanatory drawing of manufacturing method of manifold Enlarged view showing a modification of the anchor Enlarged view showing a modification of the anchor

  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 the cell stack apparatus 100. The cell stack apparatus 100 includes a manifold 200 and a cell stack 250.

[Manifold 200]
FIG. 2 is a perspective view of the manifold 200. The manifold 200 is an example of an “alloy member”.

  The manifold 200 is configured to distribute fuel gas (for example, hydrogen) to each fuel cell 300. The manifold 200 is hollow and has an internal space. Fuel gas is supplied to the internal space of the manifold 200 through the introduction pipe 204.

  The manifold 200 includes 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 disposed so as to close the upper opening of the container 202.

The top plate 201 is joined to the container 202 by a joining material 103 (not shown in FIG. 2, refer to FIG. 6). Examples of the bonding material 103 include crystallized glass, amorphous glass, brazing material, and ceramics. In the present embodiment, the crystallized glass has a ratio (crystallinity) of “the volume occupied by the crystalline phase” to the total volume of 60% or more, and the “volume occupied by the amorphous phase and impurities” with respect to the total volume. It is a glass with a proportion of less than 40%. Examples of such crystallized glass include SiO ₂ —B ₂ O ₃ system, SiO ₂ —CaO system, and SiO ₂ —MgO system.

  A plurality of insertion holes 203 are formed in the top plate 201. Each insertion hole 203 is arranged in the arrangement direction (z-axis direction) of the fuel cells 300. The insertion holes 203 are arranged at intervals from each other. Each insertion hole 203 communicates with the internal space of the manifold 200 and the outside.

  The detailed configuration of the manifold 200 will be described later.

[Cell stack 250]
FIG. 3 is a cross-sectional view of the cell stack apparatus 100. The cell stack 250 includes a plurality of fuel battery cells 300 and a plurality of current collecting members 301.

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

  The base end portion of each fuel cell 300 is inserted into the insertion hole 203 of the manifold 200. Each fuel cell 300 is fixed to the insertion hole 203 by a bonding material 101. The fuel cell 300 is fixed to the manifold 200 with 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 battery cell 300 and the insertion hole 203. Examples of the bonding material 101 include crystallized glass, amorphous glass, brazing material, and ceramics.

  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 at intervals in the arrangement direction (z-axis direction). The interval between two adjacent fuel cells 300 is not particularly limited, but can be about 1 to 5 mm.

  Each fuel cell 300 has a gas flow path 11 therein. During operation of the cell stack apparatus 100, fuel gas (such as hydrogen) is supplied from the manifold 200 to each gas flow path 11, and oxidant gas (such as air) is supplied to the outer periphery of each fuel cell 300.

Two adjacent fuel cells 300 are electrically connected by a current collecting member 301. The current collecting member 301 is joined to the base end side of each of the two adjacent fuel cells 300 via the joining material 102. The bonding material 102 is at least one selected from, for example, (Mn, Co) ₃ O ₄ , (La, Sr) MnO ₃ , and (La, Sr) (Co, Fe) O ₃ .

[Fuel battery cell 300]
FIG. 4 is a perspective view of the fuel battery cell 300. FIG. 5 is a cross-sectional view taken along the line QQ in FIG.

  The fuel battery cell 300 includes a support substrate 10 and a plurality of power generation element units 20.

(Supporting substrate 10)
The support substrate 10 includes a plurality of gas flow paths 11 extending along the longitudinal direction (x-axis direction) of the support substrate 10. Each gas flow path 11 extends from the proximal end side of the support substrate 10 toward the distal end side. Each gas flow path 11 extends substantially parallel to each other.

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

The support substrate 10 is made of a porous material that does not have electronic conductivity. The support substrate 10 can be made of, for example, CSZ (calcia stabilized zirconia). Alternatively, the support substrate 10 may be made of NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia), or made of NiO (nickel oxide) and Y ₂ O ₃ (yttria). Alternatively, MgO (magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel) may be used. The porosity of the support substrate 10 is, for example, about 20 to 60%.

(Power generation element part 20)
Each power generation element unit 20 is supported by the support substrate 10. In the present embodiment, each power generating element unit 20 is formed on both main surfaces of the support substrate 10, but may be formed only on one main surface. The power generating element units 20 are arranged 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 horizontal stripe type fuel cell. The power generating element portions 20 adjacent in the longitudinal direction are electrically connected to each other by an 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 fired body made of a porous material having electron conductivity. The fuel electrode 4 includes a fuel electrode current collector 41 and a fuel electrode active part 42.

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

  The fuel electrode current collector 41 has electronic conductivity. The fuel electrode current collector 41 preferably has higher electron conductivity than the fuel electrode active part 42. The fuel electrode current collector 41 may or may not have oxygen ion conductivity.

The fuel electrode current collector 41 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the fuel electrode current collector 41 may be composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria), or composed of NiO (nickel oxide) and CSZ (calcia stabilized zirconia). Also good. The thickness of the fuel electrode current 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 electronic conductivity. The anode active part 42 has a higher content of oxygen ion conductive material than the anode current collector 41. Specifically, the volume ratio of the substance having oxygen ion conductivity with respect to the total volume excluding the pore portion in the fuel electrode active portion 42 is determined by the oxygen ion conduction in the total volume excluding the pore portion in the fuel electrode current collector 41. It is larger than the volume ratio of the substance having the property.

  The fuel electrode active part 42 may be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the fuel electrode active part 42 may be composed of NiO (nickel oxide) and GDC (gadolinium-doped ceria). 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. Specifically, the electrolyte 5 extends in the longitudinal direction from one interconnector 31 to the adjacent interconnector 31. That is, the electrolyte 5 and the interconnector 31 are alternately and continuously arranged in the longitudinal direction (x-axis direction) of the support substrate 10. The electrolyte 5 is configured to cover both main surfaces of the support substrate 10.

  The electrolyte 5 is a fired body made of a dense material that has ionic conductivity and no electronic conductivity. The electrolyte 5 can be made of, for example, YSZ (8YSZ) (yttria stabilized zirconia). Or the electrolyte 5 may be comprised from LSGM (lanthanum gallate). The thickness of the electrolyte 5 is, for example, about 3 to 50 μm.

  The air electrode 6 is a fired body composed 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 includes an air electrode active part 61 and an air electrode current collector 62.

  The air electrode active part 61 is disposed on the reaction preventing film 7. The air electrode active part 61 has oxygen ion conductivity and electron conductivity. The air electrode active part 61 has a higher content of a substance having oxygen ion conductivity than the air electrode current collecting part 62. Specifically, the volume ratio of the substance having oxygen ion conductivity with respect to the total volume excluding the pore portion in the air electrode active portion 61 is determined by the oxygen ion conductivity in the air electrode current collector 62 with respect to the total volume excluding the pore portion. It is larger than the volume ratio of the substance having the property.

The air electrode active part 61 can be composed of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the air electrode active part 61 may have LSF = (La, Sr) FeO ₃ (lanthanum strontium ferrite), LNF = La (Ni, Fe) O ₃ (lanthanum nickel ferrite), or LSC = (La, Sr) CoO. ₃ (lanthanum strontium cobaltite) or the like. The air electrode active part 61 may be configured by two 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 collector 62 is disposed on the air electrode active part 61. The air electrode current collector 62 extends from the air electrode active part 61 toward the adjacent power generation element part. The fuel electrode current collector 41 and the air electrode current collector 62 extend from the power generation region to opposite sides. The power generation region is a region where the fuel electrode active part 42, the electrolyte 5, and the air electrode active part 61 overlap.

  The air electrode current collector 62 is a fired body made of a porous material having electronic conductivity. The air electrode current collector 62 preferably has higher electron conductivity than the air electrode active part 61. The air electrode current collector 62 may or may not have oxygen ion conductivity.

The air electrode current collector 62 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the air electrode current collector 62 may be made of LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite). Or the air electrode current collection part 62 may be comprised from Ag (silver) and Ag-Pd (silver palladium alloy). The thickness of the air electrode current collector 62 is, for example, about 50 to 500 μm.

  The reaction preventing film 7 is a fired body composed of a dense material. The reaction preventing film 7 is disposed between the electrolyte 5 and the air electrode active part 61. The reaction preventing film 7 suppresses occurrence of a phenomenon in which YSZ in the electrolyte 5 and Sr in the air electrode 6 react to form a reaction layer having a large electric resistance at the interface between the electrolyte 5 and the air electrode 6. Is provided.

The reaction preventing film 7 is made of a material containing ceria containing a rare earth element. The reaction preventing film 7 can be made of, for example, GDC = (Ce, Gd) O ₂ (gadolinium-doped ceria). The thickness of the reaction preventing film 7 is, for example, about 3 to 50 μm.

  The interconnector 31 is configured to electrically connect the power generating element portions 20 adjacent in the longitudinal direction (x-axis direction) of the support substrate 10. Specifically, the air electrode current collector 62 of one power generation element unit 20 extends toward the other power generation element unit 20. Further, the fuel electrode current collector 41 of the other power generation element unit 20 extends toward the one power generation element unit 20. The interconnector 31 electrically connects the air electrode current collector 62 of one power generating element unit 20 and the fuel electrode current collector 41 of the other power generating element unit 20. The interconnector 31 is disposed in the third recess 412 of the fuel electrode current collector 41. Specifically, the interconnector 31 is embedded in the third recess 412.

The interconnector 31 is a fired body composed of a dense material having electronic conductivity. The interconnector 31 can be made of, for example, LaCrO ₃ (lanthanum chromite). Alternatively, the interconnector 31 may be made of (Sr, La) TiO ₃ (strontium titanate). The thickness of the interconnector 31 is, for example, 10 to 100 μm.

[Detailed configuration of manifold 200]
Next, a detailed configuration of the manifold 200 will be described with reference to the drawings. 6 is a cross-sectional view taken along the line PP in FIG. FIG. 7 is an enlarged view of region A in FIG.

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

  The top plate 201 includes a base 210, a chromium oxide film 211, a coating film 212, and an anchor part 213. The container 202 includes a base material 220, a chromium oxide film 221, a coating film 222, and an anchor part 223.

  The top plate 201 and the base material 210 are examples of “alloy members”, respectively. Each of the base material 210 and the base material 220 is an example of a “base material”. Each of the chromium oxide film 211 and the chromium oxide film 221 is an example of a “chromium oxide film”. Each of the coating film 212 and the coating film 222 is an example of a “coating film”. The anchor part 213 and the anchor part 223 are examples of “anchor part”, respectively.

  Since the configuration of the container 202 is the same as the configuration of the top plate 201, the configuration of the top plate 201 will be described below with reference to FIG.

  The substrate 210 is formed in a plate shape. The substrate 210 may have a flat plate shape or a curved plate shape. Although the thickness in particular of the base material 210 is not restrict | limited, For example, it can be set as 0.5-4.0 mm.

  The substrate 210 has a surface 210a and a recess 210b. The surface 210 a is an outer surface of the base material 210. The recess 210b is formed on the surface 210a. The recess 210b may have a hole shape or a groove shape.

  The number of the recesses 210b is not particularly limited, but is preferably widely distributed on the surface 210a. Moreover, although the space | interval of the recessed parts 210b is not restrict | limited in particular, It is especially preferable that it arrange | positions at equal intervals. As a result, the anchor effect by the anchor portion 213 described later can be evenly exerted on the entire chromium oxide film 211, so that it is possible to particularly suppress the peeling of the coating film 212 from the substrate 210.

  Further, the vertical depth L1 of the concave portion 210b in the thickness direction perpendicular to the surface 210a of the substrate 210 (same as the vertical length of the anchor portion 213 described later) is the width W of the concave portion 210b in the surface direction perpendicular to the thickness direction. Larger is preferred. As a result, the biting depth of the anchor portion 213, which will be described later, can be increased, or the cross-sectional shape of the anchor portion 213 can be sharpened, so that the anchor effect by the anchor portion 213 can be further improved.

  The vertical depth L1 of the recess 210b is not particularly limited, but can be 0.5 to 300 μm, preferably 1.0 to 250 μm, and more preferably 1.5 to 200 μm. The width W of the recess 210b is not particularly limited, but can be 0.1 to 100 μm, preferably 0.15 to 70 μm, and more preferably 0.2 to 50 μm. Further, the ratio (W / L) of the width W to the vertical depth L1 of the recess 210b is not particularly limited, but is preferably 0.5 or less, and more preferably 0.3 or less.

  In FIG. 7, the concave portion 210b having a wedge-shaped cross section is illustrated, and the deepest portion of the concave portion 210b has an acute angle, but is not limited thereto. The deepest part of the recess 210b may be obtuse or rounded. Therefore, the cross-sectional shape of the recess 210b may be, for example, a semicircular shape, a rectangular shape, or other complicated shapes. Moreover, the recessed part 210b does not need to extend straight toward the inside of the base material 210, for example, may be formed diagonally with respect to the thickness direction, and may be partially bent. In FIG. 7, as an example of the concave portion 210b, a first concave portion 210bx having a linear wedge shape in cross section and a second concave portion 210by having a curved wedge shape in cross section are illustrated.

  The substrate 210 is made of an alloy material containing Cr (chromium). As such a metal material, Fe—Cr alloy steel (such as stainless steel) or Ni—Cr alloy steel can be used. Although the content rate of Cr in the base material 210 is not particularly limited, it can be 4 to 30% by mass.

The substrate 210 may contain Ti (titanium) or Al (aluminum). The Ti content in the substrate 210 is not particularly limited, but is 0.01 to 1.0 at. %. The Al content in the substrate 210 is not particularly limited, but is 0.01 to 0.4 at. %. The base material 210 may contain Ti as TiO ₂ (titania), or may contain Al as Al ₂ O ₃ (alumina).

  The chromium oxide film 211 is connected to the anchor part 213. The chromium oxide film 211 is disposed so as to cover the surface 210a of the base 210 and the surface 213a of the anchor portion 213. The chromium oxide film 211 only needs to cover at least part of the surface 210a of the base 210, but may cover substantially the entire surface 210a. The chromium oxide film 211 only needs to cover at least part of the surface 213a of the anchor portion 213, but preferably covers substantially the entire surface 213a. The chromium oxide film 211 is formed so as to close the opening of the recess 210b of the base 210. The thickness of the chromium oxide film 211 can be set to 0.5 to 10 μm.

  The coating film 212 covers at least a part of the chromium oxide film 211. Specifically, the coating film 212 covers at least a part of a region of the chromium oxide film 211 that comes into contact with the oxidant gas during the operation of the cell stack apparatus 100. The coating film 212 preferably covers the entire surface of the chromium oxide film 211 in contact with the oxidant gas. The thickness of the coating film 212 is not particularly limited, but can be, for example, 3 to 200 μm.

  The coating film 212 suppresses the volatilization of Cr from the surface 210 a of the substrate 210. Thereby, it can suppress that the electrode (this embodiment air electrode 6) of each fuel cell 300 deteriorates by Cr poisoning.

  As a material constituting the coating film 212, a ceramic material can be used. The specific type of ceramic material can be suitably selected according to the application location. In this embodiment, since the coating film 212 is applied to the manifold 200 that is required to have insulating properties, for example, alumina, silica, zirconia, crystallized glass, or the like can be used as the ceramic material. Further, when the coating film 212 is applied to a current collecting member that requires electrical conductivity, a ceramic material such as a perovskite complex oxide containing La and Sr, and Mn, Co, Ni, Fe, Cu, etc. Spinel complex oxides composed of these transition metals can be used. However, the coating film 212 only needs to suppress the volatilization of Cr, and the constituent material of the coating film 212 is not limited to the ceramic material.

  The anchor portion 213 is disposed in the concave portion 210 b of the base material 210. Anchor portion 213 is connected to coating film 212 in the vicinity of the opening of recess 210b. Thereby, since the anchor part 213 is locked to the recess 210b, an anchor effect is produced, so that the adhesion of the coating film 212 to the base material 210 can be improved. As a result, peeling of the coating film 212 from the base material 210 can be suppressed.

  The anchor portion 213 may be in contact with at least part of the inner surface of the recess 210b, but more preferably in contact with substantially the entire inner surface of the recess 210b.

  The vertical length L1 of the anchor portion 213 in the thickness direction perpendicular to the surface 210a of the substrate 210 is not particularly limited, but may be, for example, 0.1 μm or more and 300 μm or less. The vertical length L1 is the total length of the anchor portion 213 in the thickness direction of the base 210. In FIG. 7, the 1st anchor part 213x arrange | positioned in 1st recessed part 210bx and the 2nd anchor part 213y arrange | positioned in 2nd recessed part 210by are illustrated. The first anchor portion 213x has a linear wedge shape in cross section and extends straight toward the inside of the base material 210. The second anchor portion 213y has a curved wedge shape in cross section, and extends while curving obliquely toward the inside of the substrate 210. In the example shown in FIG. 7, the vertical length L1x of the first anchor part 213x is shorter than the vertical length L1y of the second anchor part 213y.

  The actual length L2 of the anchor portion 213 in the extending direction of the anchor portion 213 is not particularly limited, and can be, for example, 0.2 μm or more and 600 μm or less. The actual length L2 is the total length of a line connecting the midpoints of the anchor portions 213 in the plane direction parallel to the surface 210a of the substrate 210 from the base end portion to the tip end portion. Therefore, the actual length L2 is a concept different from the vertical length L1. In the example shown in FIG. 7, the actual length L2x of the first anchor part 213x is equal to the vertical length L1x of the first anchor part 213x, whereas the actual length L2y of the second anchor part 213y is It is longer than the vertical length L1y of the second anchor part 213y.

Anchor portion 213 contains an oxide containing Mn (manganese). Examples of the oxide containing Mn include, but are not limited to, MnO and MnCr ₂ O ₄ . Mn is an element having an equilibrium oxygen pressure lower than that of Cr (chromium) and has a higher affinity with oxygen than Cr. Therefore, during operation of the cell stack apparatus 100, Mn is transmitted through the coating film 212 and the chromium oxide film 211. The coming oxygen can be preferentially taken into the anchor part 213. Therefore, since it can suppress that the Cr contained in the area | region surrounding the anchor part 213 among the base materials 210 is oxidized, the form of the anchor part 213 can be maintained over a long period of time. As a result, since the anchor effect by the anchor part 213 is obtained over a long period of time, it is possible to prevent the coating film 212 from peeling from the base material 210 over a long period of time.

  The content ratio of Mn in the anchor portion 213 is preferably 0.01 or more in terms of cation ratio when the molar ratio of each element to the total sum of elements excluding oxygen is defined as the cation ratio. Thereby, it can suppress that Cr oxidizes more and can maintain the form of the anchor part 213 over a long period of time. The Mn content in the anchor portion 213 is more preferably 0.05 or more, and particularly preferably 0.10 or more in terms of cation ratio.

  The Mn content in the plurality of anchor portions 213 formed on the top plate 201 is obtained as follows. First, for each of 20 randomly selected anchor portions 213, the content of Mn at 10 points that divide the actual length L2 into 11 equal parts by using an EDS (energy dispersive X-ray spectrometer) as a cation ratio. taking measurement. Next, for each of the 20 anchor portions 213, the maximum value is selected from the Mn content measured at 10 points. Next, the arithmetic average of the maximum value of the content rate of Mn selected for every 20 anchor parts 213 is carried out. The value obtained by this arithmetic average is the Mn content in the anchor portion 213. If 20 anchor portions 213 cannot be observed in one cross section, 20 anchor portions 213 may be selected from a plurality of cross sections.

  The anchor portion 213 may contain an oxide containing Al (aluminum), Ti (titanium), Ca (calcium), Si (silicon), or the like in addition to the oxide containing Mn. Since these elements are elements having an equilibrium oxygen pressure lower than that of Cr, the effect of maintaining the shape of the anchor portion 213 can be expected as in the case of the oxide containing Mn described above.

  Moreover, the anchor part 213 may partially contain chromium oxide. However, the chromium content in the anchor portion 213 is preferably 0.95 or less, more preferably 0.90 or less in terms of cation ratio.

  The number of anchor portions 213 is not particularly limited, but it is preferable to observe 100 or more per 10 mm length by cross-sectional observation of the substrate surface, and more preferably 200 or more per 10 mm length. As a result, the anchor effect by the anchor portion 213 can be sufficiently increased, so that the coating film 212 can be further prevented from being peeled off from the substrate 210.

[Manufacturing method of manifold 200]
A method for manufacturing the manifold 200 will be described with reference to the drawings. In addition, since the manufacturing method of the container 202 is the same as the manufacturing method of the top plate 201, the manufacturing method of the top plate 201 is demonstrated below.

  First, as shown in FIG. 8, a recess 210 b is formed on the surface 210 a of the substrate 210. For example, by using sandblast, the wedge-shaped recess 210b can be efficiently formed. At this time, the vertical depth L1 and the width W of the concave portion 210b can be adjusted by adjusting the particle size of the abrasive or leveling the surface with a roller as appropriate.

  Next, as shown in FIG. 9, an oxide paste containing Mn is applied on the surface 210 a of the substrate 210. As a result, the recess 210b is filled with an oxide paste containing Mn. The oxide paste containing Mn can be prepared by adding ethyl cellulose and terpineol to the oxide powder containing Mn.

  Next, as shown in FIG. 10, the excess paste applied on the surface 210a is removed with, for example, a squeegee to leave the paste only inside the recess 210b.

  Next, as shown in FIG. 11, the base 210 is heat-treated in the atmosphere (800 to 900 ° C., 5 to 20 hours) to form the anchor portion 213 in the recess 210 b and to oxidize the anchor portion 213. A chromium film 211 is formed.

  Next, as shown in FIG. 12, an insulating ceramic material paste is applied on the chromium oxide film 211, and heat treatment (800 to 900 ° C., 1 to 5 hours) is performed to form a coating film 212. .

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

  In the above embodiment, the alloy member according to the present invention is applied to the manifold 200, but the present invention is not limited to this. The alloy member according to the present invention can be used as a member constituting part of the cell stack device 100 and the cell stack 250. For example, the alloy member according to the present invention can be suitably used for a current collecting member 301 that electrically connects two adjacent fuel cells 300.

Here, as described in the above embodiment, the anchor portion 213 of the alloy member contains an oxide containing Mn, and the electrical resistivity of the oxide containing Mn is chromium oxide (Cr ₂ O ₃ ). Is lower than the electrical resistivity. Therefore, compared with the case where the anchor part 213 is comprised with chromium oxide, it can suppress that the flow of the electric current in an alloy member is inhibited by the anchor part 213. Accordingly, it is possible to prevent the current from concentrating at a specific location and locally generating heat in the alloy member (base material 210), so that deterioration of the alloy member is suppressed. Thus, when the alloy member according to the present invention is used as a current collecting member, in addition to the effect of suppressing the peeling of the coating film 212 described in the above embodiment, the effect of suppressing the deterioration of the alloy member can also be expected.

  In the above embodiment, as shown in FIG. 7, the surface 213 a of the anchor portion 213 is substantially flush with the surface 210 a of the base member 210, but is not limited thereto. For example, as shown in FIG. 13, the anchor part 213 may be arrange | positioned only in the deepest part among the recessed parts 210b. In this case, the chromium oxide film 211 has only to enter the recess 210b. Moreover, as shown in FIG. 14, the anchor part 213 may protrude outside the opening part of the recessed part 210b. In this case, the chromium oxide film 211 may be disposed so as to cover a portion of the anchor portion 213 protruding from the recess 210b.

  In the above-described embodiment, the cell stack 250 has a horizontal stripe type fuel cell, but may have a so-called vertical stripe type fuel cell. The vertically striped fuel cell is disposed on a conductive support substrate, a power generation unit (a fuel electrode, a solid electrolyte layer, and an air electrode) disposed on one main surface of the support substrate, and on the other main surface of the support substrate. Interconnector.

  In the above embodiment, the anchor portion 213 is disposed in the recess 210b. However, when the base 210 has a plurality of recesses 210b, there may be a recess 210b in which the anchor portion 213 is not disposed. .

  In the above embodiment, the anchor portion 213 is connected to the chromium oxide film 211. However, when there are a plurality of anchor portions 213, the anchor portion 212 that is not connected to the chromium oxide film 211 is present. Good.

  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.

(Examples 1 to 26)
An alloy member having the configuration shown in FIG. 7 was produced as follows.

  First, a metal plate member shown in Table 1 was prepared as a base material.

  Next, a plurality of recesses were formed on the surface of the substrate by sandblasting the surface of the substrate.

  Next, an anchor part paste was prepared by adding ethyl cellulose and terpineol to an oxide containing Mn. At this time, by adjusting the amount of Mn added for each example, the Mn content in the cation ratio in the anchor portion was adjusted as shown in Table 1.

  Next, the anchor portion paste was applied onto the surface of the base material, so that each concave portion was filled with the anchor portion paste, and excess anchor portion paste remaining on the surface was removed with a squeegee.

  Next, by heat-treating the base material in the air atmosphere (850 ° C., 5 hours), the anchor portion paste filled in the recesses is solidified to form the anchor portion, and a chromium oxide film covering the anchor portion is formed. did.

  Next, a coating film paste was prepared by adding ethyl cellulose and terpineol to the coating film material powder shown in Table 1.

  Next, a coating film was formed by applying a coating film paste on the chromium oxide film and performing heat treatment (850 ° C., 2 hours).

(Comparative Examples 1-6)
In Comparative Examples 1 to 6, Comparative Example 1 was performed in the same process as Examples 1 to 26, except that the base material was heat-treated without filling the concave portion with the anchor portion paste to form a chromium oxide film in the concave portion. The alloy member which concerns on -6 was produced.

(Peel test)
A peeling test was carried out on each of Examples 1 to 26 and Comparative Examples 1 to 6 to simulate actual use environments.

  Specifically, the alloy member was put into an electric furnace, and a heating / cooling cycle of 850 ° C. × 30 min and 100 ° C. × 30 min was repeated 50 times at a temperature rising / falling rate of 200 ° C./h in an air atmosphere.

  Furthermore, after holding the alloy member in a furnace heated to 850 ° C. for 1000 hours, a heating / cooling cycle of 850 ° C. × 30 min and 100 ° C. × 30 min was further repeated 50 times at a heating / cooling rate of 200 ° C./h.

  Then, while measuring the weight change of Examples 1-26 and Comparative Examples 1-6 before and after a peeling test, the presence or absence of peeling of a coating film was confirmed by observing a cross section with an electron microscope.

  In Table 1, the case where peeling with weight change was observed was evaluated as x, the case where fine peeling was observed when observed with an electron microscope without weight change was evaluated as ◯, and the case where peeling was not observed was evaluated as ◎. did.

(Measurement of Mn content)
First, 20 anchor portions were randomly selected in a cross section perpendicular to the substrate surface, and the actual length of each anchor portion (see FIG. 7) using EDS (manufactured by Oxford, model x-act). The "Mn content" at 10 points that divide "actual length L2" into 11 equal parts was measured by a cation ratio. Next, the maximum value of the Mn content measured at 10 points was selected for each anchor part, and the arithmetic average value of this maximum value was taken as the Mn content in the anchor part formed in the alloy member.

  The contents of Mn in the anchor portions of Examples 1 to 26 and Comparative Examples 1 to 6 were as shown in Table 1. As shown in Table 1, in Comparative Examples 1 to 6, the Mn content is indicated as “less than 0.01”, but this is a measurement lower limit value of EDS and substantially does not contain Mn. Means that.

  As shown in Table 1, in Examples 1 to 26 in which an anchor portion containing an oxide containing Mn was provided, peeling of the coating film could be suppressed. This is because the oxygen that permeates through the coating film and the chromium oxide film is preferentially taken into the anchor part, thereby suppressing the oxidation of Cr existing in the area around the anchor part of the base material. This is because the shape of the part can be maintained over a long period of time.

  Moreover, as shown in Table 1, in Examples 1 to 20 in which the manganese content in the anchor portion was 0.05 or more in terms of the cation ratio, peeling of the coating film could be further suppressed.

DESCRIPTION OF SYMBOLS 100 Cell stack apparatus 200 Manifold 201 Top plate 210 Base material 211 Chromium oxide film 212 Coating film 213 Anchor part 250 Cell stack

Claims (4)

A base material having a concave portion on the surface and made of an alloy material containing chromium;
An anchor portion disposed in the recess and containing an oxide containing manganese;
A chromium oxide film connected to the anchor portion;
A coating film covering at least a part of the chromium oxide film;
An alloy member comprising: The content of manganese in the oxide containing manganese is 0.05 or more in terms of cation ratio.
The alloy member according to claim 1. Two fuel cells,
The alloy member according to claim 1 or 2,
With
The alloy member is a current collecting member that electrically connects the two fuel cells.
Cell stack. A fuel cell;
The alloy member according to claim 1 or 2,
With
The alloy member is a manifold that supports a base end portion of the fuel battery cell.
Cell stack device.

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