JP4566864B2 - Separator for polymer electrolyte fuel cell and method for producing the same - Google Patents

Description

The present invention relates to a metallic separator used for a polymer electrolyte fuel cell and a method for producing the same.

The polymer electrolyte fuel cell uses a polymer electrolyte membrane, and can be operated at a low temperature and reduced in size, and has been studied for various applications. A polymer electrolyte fuel cell forms a single cell by sandwiching a polymer solid electrolyte membrane between a pair of electrode layers, and a fuel gas such as hydrogen gas or an oxidant gas such as oxygen gas or air on the surface of the electrode layer. In general, separators for forming the diffusion layer are laminated.

FIG. 1 shows an example of the basic structure of a polymer electrolyte fuel cell. In the polymer electrolyte fuel cell illustrated in FIG. 1, separators (5a, 5b) are disposed on both sides of a unit cell (4), and a water cooling plate (6) for controlling the battery temperature is provided on one side of the separator. It has an integrated basic structure.
The single battery cell is obtained by bonding electrodes (1, 3) to both surfaces of an electrolyte membrane (2) having a thickness of 0.1 to 0.2 mm. As the electrolyte, a fluorine-based electrolyte membrane represented by NAFION (registered trademark) is generally used. Then, the basic structure shown in FIG. 1 is laminated, and an electrode and a separator are brought into contact with each other to constitute a solid polymer fuel cell.

In addition to the function of stacking the batteries as described above, the separator of the polymer electrolyte fuel cell,
A function for efficiently supplying the reaction gas to the electrode and efficiently humidifying and dehumidifying the electrolyte membrane is required.

Conventionally, a carbon material or a metal material is used as a separator used in a polymer electrolyte fuel cell. However, carbon material separators were mainly used after mixing and baking a thermosetting resin and carbon powder and then performing fine processing to form hydrogen gas and oxygen gas passages. Carbon separators are expensive to manufacture, have high electrical resistance,
Since the strength is weak and fragile, the fuel cell cannot be reduced in thickness and the fuel cell cannot be downsized.

On the other hand, as a metal material, a method of pressing a thin metal plate and providing gas supply grooves on both sides has been tried. However, there is a problem that warpage and undulation occur as a whole due to the residual stress due to press working, making it difficult to operate the fuel cell for a long time. In addition, metal ions eluted in a minute amount from the separator contaminate the electrolyte membrane, and the hydrogen ion conductivity has been significantly reduced. In addition, a stainless steel plate plated with gold or a clad plate formed with a special metal having high corrosion resistance on the surface of iron, copper or the like has been proposed, but cannot be put into practical use because of its high cost.

Properties required for the separator include corrosion resistance, stability in a redox atmosphere, electron conductivity, airtightness, mechanical strength, and low cost. As means for solving these problems, there is a fuel cell separator made of a Ni-based amorphous metal material having excellent corrosion resistance and excellent workability (Patent Documents 1 and 2).

The present inventors have so far developed many kinds of “metallic glass” defined as “amorphous metal having a supercooled liquid region”, and the Ni-based amorphous alloy exemplified in Patent Document 2 is one of them. And has high strength and high corrosion resistance (Patent Document 3). The present inventors tried to produce a separator for a fuel cell from the Ni-based metal glass sheet disclosed in Patent Document 2, and confirmed that the Ni-based metal glass as the original material has a high corrosion resistance in a thin plate shape. However, when a separator for a fuel cell was prepared in accordance with the disclosed method and a corrosion resistance test was conducted in concentrated sulfuric acid, pitting corrosion was confirmed in part, and reliability may be lacking when used as a separator. found. The cause of pitting corrosion is unknown, but it was thought that when there was a small amount of fine crystals on the plate before pressing, pitting corrosion progressed from that portion.

In order to eliminate such fine crystals, it is necessary to improve the cooling rate of the cast material from molten metal to solidification, that is, to produce a thin plate material when producing a Ni-based metallic glass plate material. become. As an invention obtained by improving the invention described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-273314), there is a method of manufacturing a separator for a fuel cell by laminating thin metal glass plates (Patent Document 4). Patent Document 4 states that “a thick plate-like amorphous metal member (specifically, a thickness of 0.05 mm or more, particularly 0.1 mm or more) that has been difficult to manufacture directly by a rapid cooling method can be easily manufactured. As described in the above, it was difficult to directly cast a metal glass plate material having a thickness of 0.05 mm or more that does not contain any crystals or the like.
The metallic glass can be molded into a predetermined shape by filling the molten metal in a mold and maintaining the supercooled liquid state (Patent Document 5). A method of manufacturing a separator by injecting a molten metal glass into a mold having a separator-shaped mold cavity using such means (Patent Document 6) is known, but this method has a larger area than the press method. It is difficult to produce a large-shaped member.

As a method for improving the corrosion resistance of the amorphous metal, various methods by adding elements that improve the corrosion resistance such as Cr and Nb are disclosed, but as another method, a method of depositing an oxide on the surface, Known (Patent Document 7). However, when the present inventors manufactured a corrosion-resistant amorphous alloy according to the disclosure of Patent Document 7, it was not possible to use it as a fuel cell separator due to high surface resistance.

Japanese Patent Laid-Open No. 2004-232070 JP 2004-273314 A JP 2000-345309 A JP-A-2005-93391 JP-A-11-323454 Japanese Patent Application Laid-Open No. 2005-685519 Japanese Patent Publication No. 61-55590

Accordingly, an object of the present invention is to provide a fuel cell separator having high strength, high corrosion resistance, excellent superplasticity, low cost and excellent performance, and a method for manufacturing the same.

In the process of studying metallic glass, the present inventors have shown that a certain metallic glass is excellent in corrosion resistance and that it can be easily processed due to the appearance of superplasticity in the supercooled liquid temperature range. I have found up to. Furthermore, as a result of intensive studies on metallic glass having the characteristics required as a separator for polymer electrolyte fuel cells, the present inventors have excellent corrosion resistance and can be superplastically processed in the supercooled liquid temperature range. The present inventors have found a highly corrosion-resistant separator using a metal glass plate material having high conductivity that is stable over time and a method for producing the same, and have completed the present invention.

That is, the present invention provides the following polymer electrolyte fuel cell separators (1) to (3) and (4
), (5) a method for producing a polymer electrolyte fuel cell separator .
(1) The material of the separator is a composition formula (Ni _1-x Zr _x ) _a Nb _b Ti _c (60 atomic% ≦ a ≦ 7
0 atom%, 5 atom% ≦ b ≦ 20 atom%, 15 atom% ≦ c ≦ 30 atom%, 0 ≦ x ≦ 0.17)
And a metal glass plate having a thickness of 0.02 to 0.5 mm, and the surface of the metal glass plate is heat-treated in an atmosphere containing oxygen and / or nitrogen.
The formed thickness of the oxide and / or nitride of the component elements in the metallic glass plate is 0.0
A solid polymer fuel having a corrosion resistant film of 03 to 0.1 [mu] m and having a concavo-convex shape formed by press molding in a supercooled liquid region so that a part of a metal glass plate becomes a gas flow path Battery separator.

(2) the thickness and wherein Rukoto such a metallic glass sheet material 0.04～0.1Mm (1
) Solid polymer fuel cell separator.

(3) The above-mentioned (1) or (2), wherein the color of the surface on which the film is formed is lightness V> 8 and saturation C <3 by color display by three attributes defined in JIS Z8729 ) Solid polymer fuel cell separator.

(4) Composition formula (Ni _1-x Zr _x ) _a Nb _b Ti _c (60 atomic% ≦ a ≦ 70 atomic%, 5 atomic% ≦ b
≦ 20 atomic%, 15 atomic% ≦ c ≦ 30 atomic%, 0 ≦ x ≦ 0.17), and a metal glass plate 11 having a thickness of 0.02 to 0.5 mm is produced. Around the metallic glass plate 11
In the press chamber P in which the atmosphere of the enclosure can be controlled, it is pressed with the press dies 15a and 15b having the concavo-convex shape 17 while being heated to the supercooled liquid region of the glass transition temperature to the crystallization temperature.
, An uneven shape which is gas flow path formed in the metal glass sheet 11, then the thickness of the oxide and / or nitride of component elements of the metallic glass plate in the surface forming the uneven shape 0.003 0.
A method for producing a separator for a polymer electrolyte fuel cell according to (1), (2) or (3), wherein a 1 μm corrosion-resistant film is formed.
(5) An uneven shape 17 serving as a gas flow path is formed on the metal glass plate 11, and then a pressing die 15
After separating a and 15b, the metal glass plate material 11 is cooled to 400 ° C. or lower, and then
The method for producing a separator for a polymer electrolyte fuel cell according to the above (4), wherein the film is formed by introducing air into the press chamber P.

The metallic glass plate material constituting the polymer electrolyte fuel cell separator of the present invention (1) to (3) has a composition formula (Ni _1-x Zr _x ) _a Nb _b Ti _c (60 atom% ≦ a ≦ 70 atom) %, 5 atomic% ≤ b ≤
20 atomic%, 15 atomic% ≦ c ≦ 30 atomic%, 0 ≦ x ≦ 0.17) alloy or <br/> Ranaru composition represented.

The composition is such that Ni is in the range of 60 atomic% to 70 atomic%, or the total content of Ni and Zr is 60 atomic% to 70 atomic%, and the ratio of Zr / (Ni + Zr) is 0.17 The composition needs to be a composition in which a part of Ni is substituted with Zr in the following range. If the contents of Zr and Ni deviate from these ranges, the corrosion resistance is low, and the constituent elements are eluted during operation of the fuel cell. The content of Ni and Zr is preferably a composition in which Ni is in the range of 62 to 68 atomic% or a composition in which Ni is 58 to 62 atomic% and Zr is 8 to 12 atomic%.

Moreover, Nb is an element which improves the corrosion resistance of the metallic glass constituting the solid polymer fuel cell separator of the present invention (1) to (3) , and must be contained in an amount of 5 atomic% to 20 atomic%. Preferably, it is 5 atomic% or more and 15 atomic% or less. Further, Ti is an element that enhances the glass forming ability of the metallic glass plate constituting the separator of the present invention, and is 15 atomic% or more and 30 atomic%.
It is necessary to contain the following.

In the solid polymer fuel cell separator of the present invention , the thickness of the metal glass plate is 0.
. Must be 02 mm or more and 0.5 mm or less, preferably 0.03 mm or more and 0.2 m
m or less, more preferably 0.04 mm or more and 0.1 mm or less. 0.02mm
If it is less than the range, pinholes are likely to be produced when the metal glass plate material is produced, and cannot be put to practical use. In addition, if the thickness exceeds 0.5 mm, the cooling rate is low when producing a metal glass plate material , so that there are many cases where crystals are contained and tend to be brittle, and when used as a fuel cell separator, crystals are included. Since corrosion similar to pitting progresses from the portion, it becomes difficult to provide a separator for a fuel cell.

In addition, the solid polymer fuel cell separator of the present invention is characterized in that it has a film made of oxides and / or nitrides of component elements in the metallic glass plate material on its surface. The film needs to be firmly attached to the metal glass plate material serving as the substrate. The adhesion of the film is difficult to evaluate in the shape of the separator, but it should not be a film that peels off by wiping with a wipe or ultrasonic cleaning. The molding conditions of the membrane film is formed on the metal glass plate material, the maximum strain of the surface by the three-point bending test shall crack even 1% or more was formed by molding conditions of the membrane does not occur.

Furthermore, the fuel cell separator of the present invention, the shape of that part of the metal glass plate material is characterized in that is provided with irregularities so that the gas flow path. Various shapes can be used so that the gas flows smoothly. The preferred shape is 0.5mm to 1mm deep
It is a shape having the following unevenness, and can have various uneven shapes depending on current collection and gas flow.

This onset bright (1) the composition of the metal glass plate, in addition to an oxide and / or nitride to a thickness and surface of the metallic glass plate, the thickness of the film of the oxide and / or nitride It prescribes. The thickness of the oxide and / or nitride film is 0.003 to 0.1 μm, preferably. The thickness is 004 to 0.05 μm, more preferably 0.005 to 0.02 μm. Within this range, the corrosion resistance can be improved without changing the internal resistance. Oxides and / or
Alternatively, when the thickness of the nitride film exceeds 0.1 μm, the electric resistance of the film increases, so that when used as a fuel cell separator, there is a problem that power generation cannot be performed with a large current.
In addition, when the oxide thickness is less than 0.003 μm, a significant improvement in corrosion resistance is not seen as compared with a metal glass plate material not forming a film, and a very small amount of crystals or the like are generated in the metal glass plate material. In such a case, corrosion similar to pitting corrosion occurs and cannot be used as a fuel cell separator.

Various methods can be used to measure the thickness of the oxide and / or nitride, but an ultrasonic method is desirable. Moreover, the metallic glass plate which has Ni as a main component used for the separator of this invention
For wood, a predetermined thickness of the oxide and / or nitride can be determined by light blue coloration is observed. When black coloring is observed, the film thickness exceeds 0.1 μm, which is not a suitable film thickness for the separator of the present invention. An oxide film is not formed on a metal glass plate that is rapidly solidified. Also, when the metal glass plate is just press-molded in the air or the metal glass plate
When press molding is performed after the oxide film is sufficiently formed on the material , the oxide film is cracked and the corrosion resistance is drastically lowered.

Furthermore, the present invention (3) the composition of the metal glass plate, in addition to having a film of oxide and / or nitride to a thickness and surface of the metallic glass sheet, the oxide and / or nitride It defines the color of the surface produced by the formation of a film. The color of the surface is characterized by lightness V> 8 and chroma C <3 due to color display by three attributes defined in JIS Z8729. Preferably, when the color H is PB, B, BG, G, V> 8 and C <3, and when the color H is otherwise, the color is V ≧ 9 and C ≦ 1, and more preferably When color H is PB, B, BG, G, V
≧ 9 and C ≦ 2.

When the thickness of the oxide and / or nitride film is increased, the surface of the film defines the configuration of the present invention (3) based on the fact that the brightness of the surface decreases from a metallic luster white. Regarding the hue, there can be various colors depending on the thickness and form of the oxide and / or nitride film, and the saturation C takes a low value of less than 3. In carrying out the present invention (4) and (5) , the thickness of the oxide film of each separator is not measured, and it is easy to make a judgment based on the color of the oxide film formed on the surface. The present invention (3) is useful for judging the conditions for performing the oxidation treatment.

Moreover, this invention (4), (5) is a manufacturing method of the separator for polymer electrolyte fuel cells,
This is a preferred method for carrying out the inventions (1) to (3) . In the present invention (4) , the thickness is 0.00.
A metal glass plate material having a thickness of 02 to 0.5 mm is prepared, and the metal glass plate material is pressed in a state where it is heated to a supercooled liquid region having a glass transition temperature to a crystallization temperature, thereby forming irregularities serving as gas flow paths. Next, an oxide and / or nitride film is formed on the uneven surface.
It is a manufacturing method of the separator for solid polymer type fuel cells of invention (1) .

In the present invention (4) , it is desirable to use a metal glass plate having a thickness close to the final shape of the fuel cell separator. Since the metallic glass plate material mainly composed of Ni and / or Zr has high strength and strength of 2000 MPa or more, it can be made thinner than conventional separators. Therefore, the preferable thickness of the separator of the present invention is 0.02 mm or more and 0.5 mm or less. In order to obtain a preferable thickness of the separator, a preferable range of the thickness before processing is 0.03 mm or more and 0.5 mm or less, and more preferably 0.04 mm or more and 0.1 mm or less. If unprocessed metal glass plate material is thinner than the thickness of a fuel cell separator desired may be a thick metallic glass sheet also by laminating a thin metallic glass sheet. Even when metal glass plates are laminated, according to the pressing method of the present invention (4) , the laminated metal glass plates can be firmly adhered to each other, so that they can be regarded as a single plate.

The temperature which heats a metal glass plate material is less than glass transition temperature-crystallization temperature. If the temperature is lower than the glass transition temperature, the metal glass plate material constituting the separator of the present invention cannot be easily processed, so it is difficult to obtain a concavoconvex shape. Breaks or breaks the mold. Also, above the crystallization temperature, a metallic glass plate
Since the material becomes brittle, it cannot be put to practical use. The preferred pressing is 20K above the glass transition temperature.
At the same time as pressing rapidly to a low temperature, press processing was started at a low pressure, the temperature was continuously increased at a low rate of temperature increase, and the processing was continued at a constant temperature in the supercooled liquid region of glass transition temperature + 30K, thereby forming a predetermined shape. This is a method of post-cooling. Even if the temperature of the metallic glass alloy is controlled in the supercooled liquid region, it may crystallize if held for a long time in the supercooled liquid region. The time until crystallization is shortened, and crystallization may occur during pressing. Softening has started from about 20K lower than the glass transition temperature, and it can be prevented from breaking even when pressed.

The speed of rapid heating to a temperature 20K lower than the glass transition temperature varies depending on the heating device, but a method of putting a sample into a furnace heated to a predetermined temperature is a good method, such as an infrared condensing furnace, 1 kHz Rapid heating by a high frequency induction heating furnace that oscillates at the above frequency or laser heating is also a desirable method. Also, the rate of temperature rise to the glass transition temperature is 10K
Lower than / min, metal glass plate material is undesirable because it tends to be brittle for crystallization during pressing. The higher the pressing pressure, the better, but it is usual to pressurize at a surface pressure of 1 to 10 MPa from the durability of the mold.

Furthermore, in the manufacturing method of this invention (4) and (5) , it is necessary to provide the process of forming the film | membrane which consists of an oxide and / or nitride. Various methods can be used for forming the oxide film and / or the nitride film. For example, heat treatment in an oxygen and / or nitrogen-containing atmosphere, reactive sputtering, laser irradiation, or the like can be used. it can. A desirable method is a method in which heat treatment is performed in air, and a method in which a press-molded metallic glass sheet material is heated at 200 to 400 ° C. for 5 to 100 minutes in an oxygen-containing atmosphere, and more preferably at 250 to 350 ° C. in air. A method of heating for 10 to 50 minutes is preferred.

When the press-molded metal glass plate material is heated in air, the formed film becomes an oxide. When the heating temperature is less than 200 ° C., formation of a film made of an oxide is not remarkable. When heated while flowing nitrogen, a film made of oxide and nitride is formed. On the other hand, when the temperature is 350 ° C. or higher, the thickness of the film increases rapidly, and it becomes difficult to make the film thickness within the range specified in the present invention (1) .
The heat treatment time varies depending on the composition of the plate material to be processed, but the time must not be extended until the plate material is crystallized.

In the present inventions (4) and (5) , a metal glass plate is processed into the shape of a fuel cell separator by pressing in a temperature range between the glass transition temperature and the crystallization temperature. After producing a metal glass sheet having a shape close to the separator, the present invention (4
) And (5) , the separators of the present invention (1) to (3) can be obtained.

Furthermore, the polymer electrolyte fuel cell separators of the present invention (1) to (3) have high wettability with water and high hydrophilicity compared to separators made of Ni-based metallic glass plates that are not oxidized. Tend. This is because the hydrophilicity is judged by visual observation, and when the surface is subjected to oxide formation treatment and the untreated plate material is sprayed with water and spread with fingers, the oxide formation treatment is performed. Metal glass plate material that has not been performed is a re-aggregation of water into a spherical shape.
Since the base metal glass plate was in a state of being spread out, the hydrophilic tendency was judged.
The tendency of high hydrophilicity is to prevent the clogging of the fuel cell voltage by preventing the clogging of the flow path due to the water discharged with the generation of power in the fuel cell separator. It is possible.

As described above, according to the present invention (4) and (5) , compared to a separator produced by a complicated process using a conventional carbon plate, only a metal glass plate material having a specific composition is pressed and subjected to an oxidation treatment. Separators can be manufactured, and significant cost reduction can be achieved during mass production. Also,
Since the separator plate can be made thin, it contributes to a compact fuel cell stack. Furthermore, the metal glass plate maintains a low internal resistance by the oxide film and / or nitride film forming process.
Since the corrosion resistance of the material is further improved, the durability of the separator is improved, and the hydrophilicity of the separator surface is increased. As a result, the fuel cell can be stably operated for a long time.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of the separators 5a and 5b. As shown in FIG. 1 (a), the separators 5 a and 5 b are formed in a plate shape, and irregularities are formed on the main surface, and the tip side of the convex portion 8 is in contact with the electrodes 1 and 3. On the other hand, the recess 7 forms a gas diffusion layer that also serves as a gas flow path between the electrode layers 1 and 3. In the present embodiment, it is desirable that the separators 5a and 5b have irregularities on both sides, and the concave portions 7 and the convex portions 8 are formed as shown in FIG. 1B in consideration of the rigidity and current collecting performance of the separators 5a and 5b. Various shapes such as a wave shape can be taken.

In the present embodiment, the metal glass plate material used for the separators 5a and 5b has a width of the supercooled liquid region represented by the difference between the crystallization temperature and the glass transition temperature in order to take a longer processing time without crystallization. It is preferable to use those having a temperature of 30K or more. More preferably, it is 50K or more.

Hereinafter, the manufacturing method of the separator for polymer electrolyte fuel cells of the present inventions (4) and (5) will be described. FIG. 2 is a conceptual diagram showing a process for producing a separator for a polymer electrolyte fuel cell made of a metallic glass plate of the present invention (1) to (3) using a press molding machine.

Metallic glass plate material 1 of a separator, which is a workpiece to be manufactured according to the present invention (4), (5)
Reference numeral 1 denotes a plate material made of metallic glass having a predetermined composition. The metal glass plate material may be produced by any known method such as a single roll method, a twin roll method, an injection molding method, or a molten metal pressure forging method, but has a defect that can be confirmed with a pinhole or an optical microscope. must not. However, the method of forming from metal glass powder by molding is highly likely to contain fine cracks between powders , and in the manufacturing method of the present invention, a method of forming an oxide film and / or a nitride film is used. However, it is not desirable because it is difficult to improve the corrosion resistance.

In the heating furnace 12 having a chamber 13 which can atmospheric adjustment, the metallic glass plate material 1
1 is placed on the holder 18. The chamber 13 is evacuated and an inert gas such as high purity Ar is introduced (step 1).

After making the inert atmosphere, the metal glass plate material 11 installed in the holder 18 is moved to the heating furnace 12, and the metal glass plate material 11 is rapidly heated to a temperature not exceeding 50K lower than the glass transition temperature. 11 is preheated (step 2).

Next, the metallic glass plate material 11 is moved using the holder 18 into the press chamber P in which the surrounding atmosphere can be controlled, and placed between the press dies 15a and 15b having the concavo-convex shape 17 (step 3). .

The pressing dies 15a and 15b are preheated by a heater 16 to a temperature not lower than 20K lower than the glass transition temperature and lower than the crystallization temperature, and the metallic glass plate 11 has a predetermined temperature due to the approach of the dies 15a and 15b. To rise. When the metal glass plate 11 rises to a predetermined temperature, it is pressurized between both molds (step 4).

The viscosity of the metal glass plate 11 is lowered by being heated to the supercooled liquid temperature range, and the pressurization easily causes plastic flow along the concave and convex shapes of the molds 15a and 15b.
The concavo-convex shapes of a and 15b are transferred to the metal glass plate material 11. And press mold 1
After separating 5a and 15b, cooling is performed until the metal glass plate 11 reaches 400 ° C. or lower, air is then introduced into the press chamber, and oxide and / or on the surface of the press-formed metal glass plate 11 A nitride film is formed (step 5).

The temperature during the formation of the oxide and / or nitride film is controlled by the distance between the molds 15a and 15b and the metallic glass plate 11 using the heat flow from the heated molds 15a and 15b. After the formation of the oxide and / or nitride film is completed in a predetermined time, the pressing dies 15a and 15b are distant from the metal glass plate 11, and the compressed gas is supplied to the press chamber P.
The metal glass plate material 11 is cooled by being introduced into the inside, and the fuel cell separator in which the oxide and / or nitride film is formed from the press chamber P into an uneven shape is taken out.

Various materials can be used for the press dies 15a and 15b used in the present invention (4) and (5) as long as the materials have high hardness at high temperature. However, graphite, quartz glass, tool steel such as SKD, beryllium copper, etc. Or chromium copper can be used preferably. In the hot forming of a metal glass plate material , when infrared rays or lasers are used as a heating source, it is possible to easily heat and cool by using a quartz glass press die.
Hereinafter, specific examples of the present invention (1) to (5) will be shown based on examples.

Ni ₆₅ Nb ₅ Ti ₃₀ (atomic%) molten alloy is quenched and solidified by a single roll quenching device to a thickness of 0.0
A 4 mm metallic glass plate was produced. When the glass transition temperature and the crystallization temperature were measured with a differential scanning calorimeter in order to determine the pressing conditions, the glass transition temperature was 818 K and the crystallization temperature was 863 K when the rate of temperature increase during the measurement was 40 K / min. there were. Next, this metallic glass plate was cut into a shape of JIS tensile test piece 14B and a 50 mm square. Only the heat treatment in air was performed on the tensile test piece, and the square plate material was press-molded by a molding apparatus.

The basic configuration of the press molding apparatus is the same as that shown in FIG. 0.8m deep in this device
A pair of molds provided with m, 1 mm wide, and 30 mm long ridges at intervals of 1 mm were attached to form an uneven shape serving as a gas flow path. After raising the temperature of the metal glass plate to 853K in the preheating furnace, it moves into the press chamber, starts pressing at a pressure of 10MPa, continues to raise the temperature to 923K while continuing to pressurize, and holds the press mold after 5 minutes Was moved from the center by 20 mm, and when the temperature reached 653 K, air was introduced into the press chamber to form an oxide film on the surface of the metal glass plate for 5 minutes. After 5 minutes, the mold was retracted to the maximum and cooled with compressed air, and the metal glass plate formed into a concavo-convex shape was taken out of the apparatus. As a result, a fuel cell separator in which the uneven shape of the mold was accurately transferred was obtained.

The thickness of the oxide film of the produced fuel cell separator is 0.05 μm, and when the surface color is compared with the color sample of Munsell, colors H = 5B, V = 9, C = 1 (5B9 / 1) Met. In addition, shape abnormalities such as warpage and waviness were not visually observed in the separator, and the depth of the groove had an accuracy within 0.01 mm of 0.8 mm, and had good shape transferability. The produced fuel cell separator was subjected to 12-hour sulfuric acid boiling corrosion test and power generation performance evaluation. The produced separator was put into a standard cell to assemble a single cell, and the internal resistance was measured from IV characteristics. Table 1 shows the results of the corrosion rate measured by the sulfuric acid boiling corrosion test, the presence or absence of pitting corrosion, the value of the internal resistance, and the result of the tensile test.

Ni ₆₀ Nb ₁₅ Ti ₁₅ Zr ₁₀ (atomic%) molten alloy is quenched and solidified by a single roll quenching device to obtain a thickness of 0.
A 08 mm metallic glass plate was produced, and pressed and film-formed using the same conditions as in Example 1 to form a fuel cell separator. The thickness of the oxide film of the produced fuel cell separator is 0.
The surface color was H = 5B, V = 9, and C = 1 (5B9 / 1). In Example 2, the test was performed in the same manner as in Example 1. The test results are shown in Table 1.

Comparative Example 1
As a comparative example, a metallic glass plate material of Ni ₆₅ Nb ₅ Ti ₃₀ (atomic%) with a thickness of 0.04 mm was produced, pressed using the same conditions as in Example 1, and the oxide film was formed without film formation. No fuel cell separator was made. The produced fuel cell separator could not be confirmed to be present at the measurement limit or below with an ultrasonic film thickness meter. Also, there was no color, and the color could not be judged due to perfect specular gloss. In Comparative Example 1, the test was performed in the same manner as in Example 1. The test results are shown in Table 1.

Comparative Example 2
The same test as in Example 1 was performed on a fuel cell separator that was cold-pressed from SUS316L stainless steel. The results are shown in Table 1.

The samples obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were subjected to a sulfuric acid boiling corrosion test. Furthermore, the power generation performance of the separators produced in Example 1 and Comparative Examples 2 and 3 was evaluated. The produced separator was put into a standard cell to assemble a single cell, and the internal resistance was measured from the IV characteristics. Table 1 shows the results of the corrosion rate measured by the sulfuric acid boiling corrosion test, the presence or absence of pitting corrosion, and the value of the internal resistance.

In Example 1 of the present invention is different from the separator of Comparative Example 1 having no oxide film in the same alloy composition, is excellent in corrosion resistance without pitting, the internal resistance indicates a value equivalent to If the formation of the oxide film is within the range specified in the present invention (1), the corrosion resistance is maintained without changing the internal resistance.
It has been found that it is possible to improve.

It is a schematic side view of the separator unit of a fuel cell. It is a conceptual diagram which shows the manufacturing process of the separator of the fuel cell of this invention (1)-(3) .

Claims (5)

The material of the separator is a composition formula (Ni _1-x Zr _x ) _a Nb _b Ti _c (60 atomic% ≦ a ≦ 70 atomic%, 5 atomic% ≦ b ≦ 20 atomic%, 15 atomic% ≦ c ≦ 30 atomic% , 0 ≦ x ≦ 0.17), and a thickness of 0.02 to 0.5 mm of the metal glass plate, and the surface of the metal glass plate contains oxygen and / or nitrogen. Formed by heat treatment in atmosphere
Was, 0.003 to thickness of oxide and / or nitride of component elements of the metallic glass plate in
For solid polymer fuel cells, characterized by having a 0.1 μm corrosion-resistant film and having a concavo-convex shape by press molding in a supercooled liquid region so that a part of the metal glass plate becomes a gas flow path Separator. The metal glass plate material having a thickness of 0.04 to 0.1 mm.
Solid polymer fuel cell separator. The color of the surface on which the film is formed is lightness V by the color display by three attributes specified in JIS Z8729.
The polymer electrolyte fuel cell separator according to claim 1 or 2, wherein> 8 and chroma C <3. Composition formula (Ni _1-x Zr _x ) _a Nb _b Ti _c (60 atomic% ≦ a ≦ 70 atomic%, 5 atomic% ≦ b ≦ 20
Atomic%, 15 atomic% ≦ c ≦ 30 atomic%, 0 ≦ x ≦ 0.17), and a metal glass plate 11 having a thickness of 0.02 to 0.5 mm is produced. cut the glass plate 11 of the surrounding
In the press chamber P in which the atmosphere can be controlled , the press flow is performed with the press dies 15a and 15b having the concavo-convex shape 17 in a state heated to the supercooled liquid region of the glass transition temperature to the crystallization temperature, and the gas channel and the becomes uneven shape formed on the metal glass plate 11,
Next , a corrosion-resistant film having a thickness of 0.003 to 0.1 μm of the oxides and / or nitrides of the component elements in the metal glass plate material is formed on the surface having the irregular shape formed thereon. Manufacturing method of the separator for solid polymer fuel cells. An uneven shape 17 serving as a gas flow path is formed on the metal glass plate 11, and then pressing dies 15a, 15b
After separating, the metal glass plate 11 is cooled until the temperature becomes 400 ° C. or lower, and then the air is
5. The method for producing a separator for a polymer electrolyte fuel cell according to claim 4, wherein the film is formed by being introduced into a press chamber P.

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