JP2003173800A - Composition for sealing, joint body and electrochemical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for sealing, which can maintain sealing performance under conditions where it is exposed to oxidizing, reducing matters in a high temperature range and also to a heating cycle between a low temperature and a high temperature. <P>SOLUTION: The composition for sealing contains 2 to 15 weight percent of BaO, 35 to 48 percent of CaO, 2 to 15 weight percent of Y<SB>2</SB>O<SB>3</SB>and 40 to 50 weight percent of Al<SB>2</SB>O<SB>3</SB>. Or, it contains 2 to 10 weight percent of MgO, 35 to 48 weight percent of CaO, 5 to 20 weight percent of Y<SB>2</SB>O<SB>3</SB>, and 40 to 45 weight percent of Al<SB>2</SB>O<SB>3</SB>. Or, thermal expansion coefficient of materials constituting object members for sealing is 8×10<SP>-6</SP>/K or more and 12×10<SP>-6</SP>/K or less, when the composition for sealing contains 5 to 20 weight percent of SrO, 35 to 45 weight percent of CaO, 2 to 15 weight percent of Y<SB>2</SB>O<SB>3</SB>, and 40 to 50 weight percent of Al<SB>2</SB>O<SB>3</SB>. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sealing composition, a bonded body, and an electrochemical device.

[0002]

2. Description of the Related Art As solid oxide fuel cells (SOFC), so-called flat plate type and cylindrical type have been proposed. Among them, the cylindrical SOFC is in the state of being most practically used, but there is a problem that the output density per unit area is low. Further, the flat plate type SOFC has a problem that sealing is difficult, although a relatively high power density can be obtained.

As described in JP-A-10-106596, a glass-based oxide bonding agent (paste) is interposed between a solid electrolyte membrane made of yttria-stabilized zirconia and a separator made of lanthanum chromite, and heat treatment is performed. In the case of bonding by means of the above, the solid solution of the silicon component contained in the glass-based oxide bonding agent accelerates the deterioration of the lanthanum chromite (0008, 0009). Further, according to the description of Japanese Patent Application Laid-Open No. 9-115530, when an attempt is made to sandwich a sealing material between the unit cells and the separator to join them, no suitable sealing material is found (0005). . This is because the sealing portion between the unit cell and the separator is exposed to both the oxidizing gas and the reducing gas at a high temperature of 800 ° C. or higher, and is repeatedly subjected to thermal cycling between room temperature and high temperature. This is because.
Further, it is because the silicon component in the glass-based bonding agent tends to react with a complex oxide forming SOFC such as lanthanum chromite at high temperature.

[0004]

Thus, the SOFC
The sealing material for use has a condition that it is stable against an oxidizing gas and a reducing gas at a high temperature of 600 ° C. or higher, particularly about 1000 ° C., and does not substantially react with the composite oxide that constitutes the SOFC. Imposed. Further, even when a thermal cycle is repeatedly applied between a high temperature of 600 ° C. or higher and a low temperature, it is necessary to prevent damage to the seal portion and gas leakage. A sealing material that satisfies such conditions is
As described in JP-A-9-115530, it is hardly known.

It is an object of the present invention to maintain sealing performance under conditions such that it is exposed to oxidizing and reducing substances in a high temperature region and is exposed to a heating cycle between low temperature and high temperature. Another object of the present invention is to provide a sealing composition.

[0006]

The present invention uses BaO in an amount of 2 to
15 wt%, CaO 35-48 wt%, Y ₂ O ₃ 2
˜15% by weight and 40 to 50% by weight of Al ₂ O ₃ , and a sealing composition, and the sealing composition, which is sealed with the sealing composition. The present invention relates to a joined body, comprising a plurality of target members.

Further, the present invention is an electrochemical device comprising an electrochemical cell and another member whose airtightness is to be maintained between the electrochemical cell, the electrochemical cell and the other member. It is provided with a sealing composition for sealing and, and the sealing composition contains 2 to 15% by weight of BaO and 35 to 4 of CaO.
8 wt%, ₂ to 15 wt% Y ₂ O ₃ , and A
characterized in that it contains 40 to 50 wt% of l ₂ O ₃ by weight.

An oxide-based bonding agent having such a composition is 600
It is stable against oxidizing gas and reducing gas at a high temperature of not less than 0 ° C., especially about 1000 ° C., and can maintain the sealing performance. Further, even when the heat cycle is repeatedly applied between a high temperature of 600 ° C. or higher and a low temperature, it is possible to prevent breakage of the seal portion and gas leakage.

When the composition of the encapsulating composition deviates from the above range, the encapsulating performance of the sealing portion is deteriorated, and the encapsulating performance after heat cycle is remarkably deteriorated. From such a viewpoint, it is particularly preferable to adopt the following composition range. BaO: 2 wt% or more, or 10 wt% or less CaO: 40 wt% or more, or 48 wt% or less Y ₂ O ₃ : 2 wt% or more, or 10 wt% or less Al ₂ O ₃ : 42 wt% Or more, or 48% by weight
Less than

In addition to the above four components, oxides of other metal elements may be contained, but the total content of oxides of these other metal elements is preferably 2% by weight or less,
It is more preferably 1% by weight or less.

The present invention also contains MgO in an amount of 2 to 10% by weight, CaO in an amount of 35 to 48% by weight, Y ₂ O _{3 in an amount} of 5 to 20% by weight, and Al ₂ O ₃ in an amount of 40 to 45% by weight. The present invention relates to a sealing composition, and is provided with the sealing composition and a plurality of target members sealed by the sealing composition. And a bonded body.

Further, the present invention comprises an electrochemical cell having a gas-tight solid electrolyte, an anode and a cathode, and another member whose airtightness should be maintained between the electrochemical cell and the electrochemical cell. An electrochemical device, comprising a sealing composition for sealing an electrochemical cell and other members, the sealing composition containing 2 to 10% by weight of MgO and 35 to 4 of CaO.
8 wt%, Y ₂ O ₃ 5-20 wt%, and Al ₂ O
₃ is contained in an amount of 40 to 45% by weight.

The oxide-based bonding agent having such a composition is 600
It is stable against oxidizing gas and reducing gas at a high temperature of not less than 0 ° C., especially about 1000 ° C., and can maintain the sealing performance. Further, even when the heat cycle is repeatedly applied between a high temperature of 600 ° C. or higher and a low temperature, it is possible to prevent breakage of the seal portion and gas leakage.

When the composition of the encapsulating composition deviates from the above range, the encapsulating performance of the sealing part is deteriorated, and the encapsulating performance after the heat cycle is remarkably decreased. From such a viewpoint, it is particularly preferable to adopt the following composition range. MgO: 2 wt% or more, or 8 wt% or less CaO: 40 wt% or more, or 45 wt% or less Y ₂ O ₃ : 10 wt% or more, 15 wt% or less Al ₂ O ₃ : 40 wt% Or more, or 45% by weight
Less than

In addition to the above four components, oxides of other metal elements may be contained, but the total content of oxides of these other metal elements is preferably 2% by weight or less,
It is more preferably 1% by weight or less.

Further, according to the present invention, the thermal expansion coefficient of the material constituting the member to be sealed is 8 × 10 ⁻⁶ / K or more, 12 × 1.
0 ^-6 / K or less, 5 to 20 wt% of SrO, Ca
O 35 to 45 _wt%, a Y 2 _{O 3} 2 to 15 wt%, and _Al a 2 _{O 3,} characterized in that it contains 40 to 50 wt%, the sealing composition, and, for the sealing A composition,
The present invention relates to a joined body, which comprises a plurality of target members sealed by this sealing composition.

The present invention also provides an airtight solid electrolyte, a positive electrode.
An electrochemical cell with a pole and a cathode and this electrification
Other elements that should be kept airtight from the science cell.
And an electrochemical cell and the other
The sealing composition for sealing the member of
The stopping composition contains 5 to 20% by weight of SrO and 35% of CaO.
~ 45% by weight, Y_TwoO_Three2 to 15% by weight, and
And Al_TwoO _ThreeIs contained in an amount of 40 to 50% by weight.
To do.

The oxide-based bonding agent having such a composition is 600
It is stable against oxidizing gas and reducing gas at a high temperature of not less than 0 ° C., especially about 1000 ° C., and can maintain the sealing performance. Further, even when the heat cycle is repeatedly applied between a high temperature of 600 ° C. or higher and a low temperature, it is possible to prevent breakage of the seal portion and gas leakage.

When the composition of the encapsulating composition deviates from the above range, the encapsulating performance of the sealing portion is deteriorated and the encapsulating performance after the heat cycle is remarkably deteriorated. From such a viewpoint, it is particularly preferable to adopt the following composition range. SrO: 5 wt% or more, or 15 wt% or less CaO: 40 wt% or more, or 48 wt% or less Y ₂ O ₃ : 2 wt% or more, or 10 wt% or less Al ₂ O ₃ : 42 wt% Or more, or 48% by weight or less

In addition to the above four components, oxides of other metal elements may be contained, but the total content of oxides of these other metal elements is preferably 2% by weight or less,
It is more preferably 1% by weight or less.

Incidentally, this CaO-Al ₂ O ₃ -Y ₂ O ₃
-SrO-based encapsulating composition is disclosed in Japanese Examined Patent Publication Sho 56-19318.
The composition is the same as that described in the publication.
However, Japanese Patent Publication No. 56-19318 describes that it is suitable as a sealing composition for a member having a coefficient of thermal expansion of 8 × 10 ⁻⁶ / K or more and 12 × 10 ⁻⁶ / K or less. In addition, it does not describe the durability when exposed to an oxidizing gas and a reducing gas at a temperature of 600 ° C. or higher.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the coefficient of thermal expansion of a target member to be sealed is preferably 8 × 10 ⁻⁶ /
It is preferably K or more and 12 × 10 ⁻⁶ / K or less.

The oxidizing gas is not particularly limited as long as it is a gas capable of supplying oxygen ions to the solid electrolyte membrane, and examples thereof include air, diluted air, oxygen and diluted oxygen.

As the reducing gas, H ₂ , CO, CH ₄
And these mixed gases can be illustrated.

The electrochemical cell targeted by the present invention means a general cell for causing an electrochemical reaction.

For example, the electrochemical cell can be used as an oxygen pump or a high temperature steam electrolysis cell. The high temperature steam electrolysis cell can be used in a hydrogen production device and also in a steam removal device. In addition, the electrochemical cell is set to NOx, SO
It can be used as a decomposition cell of x. This decomposition cell can be used as a device for purifying exhaust gas from automobiles and power generators. Further, in a preferred embodiment, the electrochemical cell is a solid oxide fuel cell.

The member to be sealed is a ceramic member,
It may be a metal member or a ceramic-metal composite material. Preferably, at least a ceramic member is included. The type of ceramics is not limited, but zirconia, lanthanum chromite, lanthanum manganite, magnesia-
It may be an alumina spinel. Further, as the composite material, a metal-zirconia cermet such as nickel-zirconia cermet can be exemplified. As a metal, 94C
refractory metal such as r5Fe1Y ₂ O ₃ and the like.

When the encapsulating composition of the present invention is applied to an electrochemical cell, among the constituent members of the electrochemical cell, a solid electrolyte, an interconnector, an anode, a cathode, a flange,
It is preferably applied to a gas supply member such as a manifold or a supply pipe.

The material that can be used as the interconnector is not particularly limited as long as it has electronic conductivity, but it is a perovskite type complex oxide containing lanthanum for the reason of heat resistance. More preferably, lanthanum chromite is preferable from the viewpoint of heat resistance, oxidation resistance, and reduction resistance.

The material that can be used as the solid electrolyte is not particularly limited as long as it has ionic conductivity, but yttria-stabilized zirconia or yttria partially-stabilized zirconia is used because of its high oxygen ion conductivity. Cerium oxide is preferred.

The anode is not particularly limited as long as it is a reducing catalyst, and is preferably a perovskite type complex oxide containing lanthanum because of its high oxygen reducing property, and further, lanthanum manganite or Lanthanum cobaltite is preferred. Palladium, platinum,
Ruthenium, platinum-zirconia mixed powder, palladium-zirconia mixed powder, ruthenium-zirconia mixed powder, platinum-cerium oxide mixed powder, ruthenium-cerium oxide mixed powder and the like can also be used.

Although lanthanum chromite and lanthanum manganites can be used alone, strontium, calcium, and
Chromium (for lanthanum manganese), cobalt,
It is also possible to dope with iron, nickel, aluminum and the like.

Materials that can be used as the cathode are
Although it is not particularly limited as long as it is an oxidation catalyst, nickel, palladium,
Platinum, nickel-zirconia mixed powder, platinum-zirconia mixed powder, palladium-zirconia mixed powder, nickel-cerium oxide mixed powder, platinum-cerium oxide mixed powder, palladium-cerium oxide mixed powder, ruthenium,
It is preferable to use ruthenium-zirconia mixed powder.

When an electrochemical cell and an external manifold are used and an oxidizing gas or a reducing gas is distributed from the manifold, the material of the manifold is magnesia-alumina spinel, zirconia, or alumina. preferable.

In a preferred embodiment, the electrochemical cell has a honeycomb-shaped support, and at least a part of the support is made of a gas-tight solid electrolyte material. Then, a plurality of oxidizing gas channels and a plurality of reducing gas channels are provided, the oxidizing gas channel faces the anode, and the reducing gas channel faces the cathode. Particularly preferably, the sealing composition of the present invention is used for a honeycomb-shaped electrochemical cell and a manifold for supplying each gas to each oxidizing gas channel and each reducing gas channel. And join.

The method for producing the encapsulating composition of the present invention is not limited, but the following method is preferable. First, an oxide of each metal element, or a substance that produces an oxide of each metal element after heating (a precursor of a metal oxide) is prepared,
Mix and dry. At this stage, wet mixing is preferable. When the starting material is a metal oxide precursor,
This mixture is calcined and the calcined product is crushed. Examples of the precursor include inorganic salts such as nitrides, carbides, carbonates, sulfates and nitrates, and organic metal compounds such as oxalates and alkoxides. A binder such as polyvinyl alcohol is added to the mixture thus obtained and mixed well to prepare a paste-like or solid-state sealing mixture.

Next, the obtained sealing mixture is applied onto a predetermined sealing surface and heated to melt. Alternatively, by molding the obtained mixture for sealing, a molded body having a flat shape of the sealing surface can be manufactured, and this molded body can be placed at a target location and heated to melt. The atmosphere at the time of heating and melting may be an oxidizing atmosphere such as air. A suitable heating temperature varies depending on the composition, but is usually preferably 1300 to 1550 ° C, and 1350 to 1350.
1500 ° C. is more preferable. By cooling the heated melt, a polycrystal sealing composition is obtained.

[0038]

[Experiment 1] (Molding of mixed powder for sealing) Powders of barium carbonate, calcium carbonate, yttrium trioxide, and dialuminum trioxide were mixed. However, the respective raw material powders were blended so that the ratio of each metal oxide was the ratio shown in Table 1 (shown by weight% unit). To this prepared powder, 2% by weight of polyvinyl alcohol (organic binder) and water were added and wet-mixed, and the resulting slurry was dried and crushed to obtain a mixed powder for sealing. The obtained mixed powder for sealing was molded by a die pressing method to produce a ring-shaped molded body 4 having an outer diameter of 10 mm, an inner diameter of 8 mm and a thickness of 0.5 mm as shown in FIG. 1 (a). .

(Production of member to be sealed) 2% by weight of polyvinyl alcohol was added to 98% by weight of 8 mol yttria-stabilized zirconia powder to prepare a powder for press molding. This powder is press-molded, outer diameter 14 mm, inner diameter 1
A pipe-shaped molded body having a length of 2 mm and a length of 50 mm was produced.
The compact was fired in air at 1400 ° C. for 3 hours. The obtained fired body was processed to obtain cylindrical members 6 and 7 having an outer diameter of 10 mm, an inner diameter of 8 mm and a length of 30 mm.

(Joining) The molded body 4 and the cylindrical member 6,
7 and 7 were set in an electric furnace as shown in FIG. In the air atmosphere, the temperature was raised to 1400 ° C. at 200 ° C./hour, and the temperature was maintained at 1400 ° C. for 1 hour to melt the molded body 4. Next, it was cooled to obtain a joined body 5 composed of a cylindrical member 6 made of stabilized zirconia / a sealing composition 8 / a cylindrical member 7 made of stabilized zirconia, as shown in FIG. 1 (b).

(Leak Test) The bonded body 5 was set as schematically shown in FIG. However, 9 is a lid for sealing the cylindrical bonded body 5, and 10 and 11 are pedestals. A helium leak detector is used, and arrow A is drawn from one side.
As in the inner space 12 by vacuum suction, 10 ^-9 Tor
Helium gas was blown to the seal portion at a sensitivity of r to measure. A leak test was performed on five tests, and one in which no leak was found was accepted. Then, the evaluation was performed based on the number of passed leak tests. The results are shown in Table 1.

[0042]

[Table 1]

As can be seen from these results, by using the sealing composition of the present invention, it was possible to secure high airtightness when the seal portion was formed by heating and melting. The encapsulant of each comparative example is likely to be cracked after cooling mainly due to the mismatch of thermal expansion, and therefore, it is considered that a high degree of airtightness cannot be maintained.

[Experiment 2] Powders of magnesium oxide, calcium carbonate, yttrium trioxide and dialuminum trioxide were prepared. However, the respective raw material powders were weighed and mixed so that the ratios shown in Table 2 were obtained. This mixed powder 98
2% by weight of polyvinyl alcohol and water were added to the weight% and wet-mixed, and the obtained slurry was dried and crushed to obtain a mixed powder for sealing. Thereafter, each bonded body was manufactured in the same manner as in Experiment 1 and the airtightness was evaluated. The results are shown in Table 2.

[0045]

[Table 2]

As can be seen from these results, by using the sealing composition of the present invention, it was possible to secure high airtightness when the seal portion was formed by heating and melting. The encapsulant of each comparative example is likely to be cracked after cooling mainly due to the mismatch of thermal expansion, and therefore, it is considered that a high degree of airtightness cannot be maintained.

[Experiment 3] Powders of strontium carbonate, calcium carbonate, yttrium trioxide and dialuminum trioxide were prepared. However, the respective raw material powders were weighed and mixed so that the ratios shown in Table 3 were obtained. 2% by weight of polyvinyl alcohol and water were added to the obtained mixed powder and wet-mixed, and the obtained slurry was dried and crushed to obtain a mixed powder for sealing. Thereafter, each bonded body was manufactured in the same manner as in Experiment 1 and the airtightness was evaluated. The results are shown in Table 3.

[0048]

[Table 3]

As can be seen from these results, by using the sealing composition of the present invention, it was possible to secure high airtightness when the seal portion was formed by heating and melting. The encapsulant of each comparative example is likely to be cracked after cooling mainly due to the mismatch of thermal expansion, and therefore, it is considered that a high degree of airtightness cannot be maintained.

[Experiment 4] (Production of each target member 6) 2% by weight of polyvinyl alcohol was added to 98% by weight of 8 mol yttria-stabilized zirconia powder to prepare a powder for press molding. This powder is press-molded to have an outer diameter of 14 mm, an inner diameter of 12 mm, and a length of 5
A 0 mm pipe-shaped molded body was produced. After firing this formed body 2 in air at 1400 ° C. for 3 hours, the obtained fired body is processed to have an outer diameter of 10 mm, an inner diameter of 8 mm and a length of 30 m.
m cylindrical member 6 was obtained.

(Production of Target Member 7) 2% by weight of polyvinyl alcohol was added to 98% by weight of magnesia-alumina spinel powder to prepare a powder for press molding.
This powder is press molded to have an outer diameter of 14 mm and an inner diameter of 12 m.
A pipe-shaped molded body having m and a length of 50 mm was produced. This molded body is fired in air at 1500 ° C. for 3 hours, and the obtained fired body is processed to have an outer diameter of 10 mm, an inner diameter of 8 mm, and a length of 30.
A cylindrical member 7 of mm was obtained.

(Manufacture of bonded body A) Raw material powders were blended so as to have the compositions of Experiment Nos. 1-17, 2-8, and 3-15 shown in Experiments 1 to 3. To this powder, 2% by weight of polyvinyl alcohol and water were added and wet-mixed, and the obtained slurry was dried and crushed to obtain a mixed powder for sealing.
Each mixed powder is molded by the die pressing method, and the outer diameter is 10m.
m, an inner diameter of 8 mm, and a thickness of 0.5 mm, each ring-shaped molded body 4 was produced.

The members 6 and 7 and the molded body 4 are shown in FIG.
It was set in an electric furnace as shown in (a). In the air, the temperature is raised to 1450 ° C at 200 ° C / hour, and 1450 ° C.
The molded body 4 was melted by holding for 1 hour. Then, it is cooled, and the member 6 consisting of stabilized zirconia 6 / sealing composition 8
A joined body 5 including a member 7 made of / magnesia-alumina spinel was obtained. This joined body is referred to as a joined body A.

(Production of bonded body B) Further, the bonded body A described above is used.
In, the material of the cylindrical member 6 was changed to calcium dope lanthanum chromite. Specifically, 2% by weight of polyvinyl alcohol is added to 98% by weight of calcium dope lanthanum chromite powder to prepare a powder for press molding, and this powder is press molded to have an outer diameter of 14 mm, an inner diameter of 12 mm, and a length of 50 mm. The pipe-shaped molded body of was produced. This molded body is fired in air at 1500 ° C. for 3 hours,
The obtained fired body is processed to have an outer diameter of 10 mm, an inner diameter of 8 mm,
A cylindrical member 6 having a length of 30 mm was obtained. Then, this member 6 was joined to the member 7 as described above. The obtained bonded body was bonded to the bonded body B (member 6 / lanthanum chromite).
This is referred to as a sealing composition 8 / member 7) made of magnesia-alumina spinel.

Comparative Example 1 Titanium dioxide 9% by weight, dialuminum trioxide 23% by weight, silicon dioxide 48% by weight,
Each powder was prepared with a composition of 19% by weight of manganese oxide. The thermal expansion coefficient of the crystallized product having this composition is close to the thermal expansion coefficient of zirconia, and thus was used as a comparative sample. After mixing this powder,
The prepared powder was put in a platinum crucible and melted at 1400 ° C. for 3 hours, and the melt was put into water and cooled to prepare a glass lump. This glass was crushed in an alumina mortar to obtain a powder (powder of Comparative Example 1) having an average particle size of 5 μm. 2% by weight of polyvinyl alcohol and water were added to this powder and wet-mixed, and the obtained slurry was dried and crushed to obtain a sealing powder. This powder is molded by a die pressing method and has an outer diameter of 10 m.
A ring-shaped molded body having m, an inner diameter of 8 mm and a thickness of 0.5 mm was produced.

The above-mentioned members 6 and 7 and the molded body 4 for sealing were set in an electric furnace as shown in FIG. 1 (a). In an air atmosphere, the temperature was raised to 1200 ° C. at a heating rate of 200 ° C./hour, and the temperature was kept at 1200 ° C. for 3 hours. Then, it cools and the member 6 which consists of stabilized zirconia / sealing composition 8
/ Member 7 made of magnesia-alumina spinel (joined body A) or member 6 made of lanthanum chromite
A member 7 (bonded body B) made of the sealing composition 8 / magnesia-alumina spinel was produced.

Comparative Example 2 2% by weight of polyvinyl alcohol was added to 98% by weight of Pyrex (registered trademark) glass powder (powder of Comparative Example 2) to prepare a powder for press molding. This powder was molded by a die pressing method to prepare a ring-shaped molded body 4 having an outer diameter of 10 mm, an inner diameter of 8 mm and a thickness of 0.5 mm. This molded body 4 and the above-mentioned members 6, 7
And were set in an electric furnace as shown in FIG.
In an air atmosphere, the temperature was raised to 860 ° C. at a heating rate of 200 ° C./hour, and the temperature was maintained at 860 ° C. for 1 hour to melt the molded body 4.
Then, it cools, and the member 6 which consists of stabilized zirconia / sealing composition 8 / member 7 which consists of magnesia-alumina spinel (joined body A) or member 6 which consists of lanthanum chromite / sealing composition 8 / A member 7 (bonded body B) made of magnesia-alumina spinel was manufactured.

(Leak Test) Each bonded body 5 was set as shown in FIG. Specifically, the lids 1 are provided on both ends of each bonded body 5.
2, 13 were fixed via O-rings. One lid 1
Nitrogen gas was introduced from the No. 3 side through the supply pipe 14 as shown by an arrow B, the pressure was observed by the gauge 15, the pressure was maintained at 1 atm by the gauge pressure, and the leak amount from the bonded body 5 was measured by the mass flow meter 16. did. Next, the bonded body was immersed in an alcohol solution, and the presence or absence of gas leak at the bonded portion was observed. The results of these measurements are shown in Table 4.

(Heat Cycle Test) A heat cycle test was performed in the atmosphere. Five sets of pipe-shaped joined bodies were set in an electric furnace. Temperature rising rate of 200 ℃ in air
The temperature was raised to 1200 ° C./hour, the temperature was kept at 1200 ° C. for 1 hour, then the temperature was lowered to 100 ° C. at a temperature decreasing rate of 200 ° C./hour, and the temperature was kept at 100 ° C. for 1 hour. This heating / cooling cycle was repeated 5 times to perform a thermal cycle test. Then, the leak test was performed. Further, the same heat cycle test was carried out in a hydrogen atmosphere. That is, the temperature was raised to 1200 ° C. at a temperature rising rate of 200 ° C./hour in a hydrogen atmosphere and maintained at 1200 ° C. for 1 hour, and then the temperature lowering rate was set to 20.
The temperature was lowered to 100 ° C. at 0 ° C./hour, and the temperature was kept at 100 ° C. for 1 hour. This heating / cooling cycle was repeated 5 times to perform a thermal cycle test. Then, the leak test was performed. The results of these measurements are shown in Table 4.

(Measurement of Coefficient of Thermal Expansion) 3 × 3 × from 8 mol yttria-stabilized zirconia, magnesia-alumina spinel, calcium dope lanthanum chromite sintered body
Cut out a 20 mm square bar and increase the temperature at a rate of 10 ° C / min to 40
The coefficient of thermal expansion was measured from 0 ° C to 800 ° C to obtain the coefficient of thermal expansion of 800 ° C. Table 5 shows the measurement results. Experiment number 1-1
7, 2-8, 3-15 and the powders of Comparative Examples 1 and 2 to 14
After melting at 50 ℃, cool and lump 3 × 3 × 20mm
The square bar of was cut out and the coefficient of thermal expansion was measured in the same manner as above. However, for Comparative Example 2, the coefficient of thermal expansion at 40 to 450 ° C. was measured.

[0061]

[Table 4]

[0062]

[Table 5]

As can be seen from the above results, in the examples of the present invention, good results were obtained for both the bonded bodies A and B.
On the other hand, in Comparative Example 1, the thermal expansion is consistent, but the amount of leak is large because the adhesiveness at the interface with each of the sintered bodies 6 and 7 is poor. In Comparative Example 2, gas leakage was observed after the sealing mixture was heated and melted, probably due to the difference in thermal expansion, and the amount of gas leakage increased after the thermal cycle.

[Experiment 5] (Production of Honeycomb Cell) A honeycomb-type cell 21 having a cross section as shown in FIG. 5 was produced. 5 parts by weight of methyl cellulose and 18 parts by weight of water were added to 100 parts by weight of 8 mol yttria-stabilized zirconia powder and kneaded to prepare a kneaded material for extrusion molding. Similarly, a kneaded material of lanthanum chromite powder was prepared. Honeycomb dies (30 mm long × 9 mm wide, hole pitch 3 mm,
A wall thickness of 300 μm) was set, and a laminated honeycomb molded body having three layers of lanthanum chromite / zirconia / lanthanum chromite was formed. This molded body has a cross-sectional shape shown in FIG. The formed body was dried at 100 ° C. and fired in air at 1500 ° C. for 3 hours to produce a honeycomb-shaped support body 29. The support 29 is composed of two lanthanum chromite layers 22A and 22B and a zirconia layer 23 between them. Each lantern chromite layer 22
Through holes 24 and 25 are formed by A and 22B and the intermediate zirconia layer 23. In this example, the lanthanum chromite layers 22A and 22B act as interconnectors or separators, and the zirconia layer 23 acts as a solid electrolyte part.

(Preparation of Manifold) 2% by weight of polyvinyl alcohol was added to 98% by weight of magnesia-alumina spinel powder to prepare a powder for press molding.
This powder was press-molded to prepare a molded body having a length of 30 mm, a width of 15 mm and a thickness of 12 mm. In the air,
Manifold 1 shown in FIG. 4 after firing at 1500 ° C. for 3 hours
5A and 15B were produced.

(Cell 21 and manifold 15A, 15B
Joining with) Experiment Nos. 1-17 and 2-described in Experiments 1 to 3
Each raw material powder was prepared so as to have each composition of 8 and 3-15. To this prepared powder, 2 parts by weight of methyl cellulose and alcohol were added to form a paste. This paste was applied to both end faces of the honeycomb cell 21, and the manifolds 15A and 15B were adhered to each other. Then, gas supply pipes 13A, 13B, 14A, 14B made of magnesia-alumina spinel were inserted into the through holes of the manifold. The above-mentioned paste was also interposed between each gas supply pipe and the manifolds 15A and 15B. The assembly was dried and set in an electric furnace. 20 in the atmosphere
The temperature was raised to 1400 ° C at a heating rate of 0 ° C / hour,
It was kept at 0 ° C. for 1 hour and then cooled to obtain the joined body of FIG. Here, the manifolds 15A, 15B and the cells 21 are joined by the sealing compositions 17A, 17B, respectively, and the manifolds 15A, 15B and the gas supply pipes 13A, 13B, 14A, 14B are sealed. They are joined together by the composition 18 for use.

(Production of Electrode) Next, platinum slurry was applied to the inner surfaces of the through holes 24 and 25 of the honeycomb-shaped support 29, and platinum was baked at 1000 ° C. to form the anode 26 and the cathode 27. Therefore, in this example, 19 acts as an oxidizing gas passage and 20 acts as a reducing gas passage.

A leak test was conducted on the obtained bonded body under the same conditions as in Experiment 4. However, one gas supply pipe 1
Nitrogen gas was caused to flow through 3A, and the outlet of the gas supply pipe 13B was sealed with a lid. The amount of gas leak was 0.02 cc / min or less in all three types of sealing compositions. Also, no gas leak was observed when the bonded body was observed by immersing it in alcohol. Next, nitrogen gas was caused to flow through the other gas supply pipe 14A, and the outlet of the supply pipe 14B was sealed with a lid. Then, the leak test described above was performed. Gas leak amount is 0.0
It was 2 cc / min or less. Also, no gas leak was observed when the bonded body was observed by immersing it in alcohol.

(Power Generation Test) A platinum mesh 16 for current collection was set for each of the above-mentioned three types of bonded bodies that had been subjected to the leak test. Air was supplied to the gas supply pipe 13A, hydrogen gas was supplied to the gas supply pipe 14A, and argon gas was caused to flow around the bonded body to perform a power generation test. The temperature was raised to 1000 ° C. at a temperature rising rate of 200 ° C./min, and the temperature was kept at 1000 ° C. for 8 hours for power generation. Then, stop the power generation, 20
The temperature was lowered to 0 ° C. This operation was repeated 5 times, and then the cell 21 was taken out from the power generator and the leak test was performed. In all samples, the gas leak rate was 0.02 cc / min or less. Also, no gas leak was observed when the bonded body was observed by immersing it in alcohol. In this example, the power generation test was performed using one cell 21, but power generation was also possible when two or more cells 21 were stacked to form a stack.

[0070]

As described above, according to the present invention, exposure to oxidizing and reducing substances in a high temperature range,
Further, it is possible to provide the encapsulating composition capable of maintaining the encapsulating performance under the condition that it is exposed to the heating cycle between the low temperature and the high temperature.

[Brief description of drawings]

FIG. 1A is a front view showing an assembly of members 6 and 7 to be sealed and a molded body 4 of a mixed powder for sealing, and FIG. It is a front view which shows the joined body 5 obtained by making it.

FIG. 2 is a schematic diagram showing a leak test method for a bonded body 5.

FIG. 3 is a schematic diagram showing a leak test method for the bonded body 5.

FIG. 4 is a schematic diagram showing how the manifold and the gas supply pipe are attached to the cell 21.

5 is a cross-sectional view showing a cell 21. FIG.

[Explanation of symbols]

4 Molded body of mixed powder for sealing 5 Bonded body
6, 7 Target member for sealing 8 Composition for sealing 13A, 13B, 14A, 14B Gas supply pipe 15A, 15B Manifold 17
A, 17B, 18 Sealing composition 19 Oxidizing gas flow path 20 Reducing gas flow path 21
Solid electrolyte fuel cell 22A, 22B Separator 23 Solid electrolyte part 26 Anode
27 Cathode 29 Honeycomb-shaped support

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinji Kawasaki             2-56, Sudacho, Mizuho-ku, Nagoya-shi, Aichi             Inside Hon insulator Co., Ltd. F-term (reference) 4G026 BA05 BB02 BB05 BB21 BE02                       BF04 BF42 BG02                 5H026 AA06 BB01 BB08 CC06 CX06                       EE12 HH00 HH05 HH08

Claims (17)

[Claims] 1. BaO is 2 to 15% by weight, and CaO is 35 to 35% by weight.
48 wt%, ₂ to 15 wt% Y ₂ O ₃ , and Al ₂
A sealing composition comprising 40 to 50% by weight of O ₃ . 2. The encapsulating composition according to claim 1, wherein the target member to be sealed contains at least a ceramic member. 3. The material constituting the target member to be sealed
Thermal expansion coefficient is 8 × 10 ^-6/ K or more, 12 × 10^-6
/ K or less, claim 1 or 2, characterized in that
The encapsulating composition described above. 4. The method according to claim 1, wherein the material is exposed to an oxidizing gas and a reducing gas at a temperature of 600 ° C. or higher.
The encapsulating composition according to claim 1. 5. An encapsulating composition according to any one of claims 1 to 4, and a plurality of target members sealed by the encapsulating composition. The feature is a bonded body. 6. An electrochemical device comprising an electrochemical cell having an airtight solid electrolyte, an anode and a cathode, and another member whose airtightness is to be maintained between the electrochemical cell. It is provided with a sealing composition that seals the electrochemical cell and the other member, and the sealing composition contains 2 to 2 BaO.
15 wt%, CaO 35-48 wt%, Y ₂ O ₃ 2
˜15 wt% and Al ₂ O ₃ 40-50 wt%, Electrochemical device. 7. MgO of 2 to 10% by weight and CaO of 35 to 35% by weight.
48 wt%, Y ₂ O ₃ 5-20 wt%, and Al ₂
O _3, characterized in that it contains 40-45% by weight, the sealing composition. 8. The encapsulating composition according to claim 7, wherein the target member to be sealed includes at least a ceramic member. 9. The material forming the target member to be sealed
Thermal expansion coefficient is 8 × 10 ^-6/ K or more, 12 × 10^-6
/ K or less, claim 7 or 8 characterized in that
The encapsulating composition described above. 10. The encapsulating composition according to claim 7, wherein the encapsulating composition is exposed to an oxidizing gas and a reducing gas at a temperature of 600 ° C. or higher. object. 11. An encapsulating composition according to any one of claims 7 to 10, and a plurality of target members sealed by the encapsulating composition. The feature is a bonded body. 12. An electrochemical device comprising an electrochemical cell including a gas-tight solid electrolyte, an anode and a cathode, and another member whose airtightness is to be maintained between the electrochemical cell and the electrochemical cell. There is provided a sealing composition for sealing the electrochemical cell and the other member, and the sealing composition contains MgO in an amount of 2 to
10 wt%, CaO 35-48 wt%, Y ₂ O ₃ 5
˜20 wt% and 40 to 45 wt% Al ₂ O ₃ by weight. 13. A material constituting a member to be sealed has a thermal expansion coefficient of 8 × 10 ⁻⁶ / K or more and 12 × 10 ⁻⁶ / K or less, 5 to 20 wt% of SrO and 35 of CaO. ~ 45
Wt%, ₂ to 15 wt% Y ₂ O ₃ , and Al ₂ O ₃
40 to 50% by weight of the sealing composition. 14. The encapsulating composition according to claim 13, which is exposed to an oxidizing gas and a reducing gas at a temperature of 600 ° C. or higher. 15. A sealing composition which is exposed to an oxidizing gas and a reducing gas at a temperature of 600 ° C. or higher, which comprises S
rO 5 to 20% by weight, CaO 35 to 45% by weight, Y
The ₂ O ₃ 2 to 15 wt%, and _Al 2 _{O 3} 40 to 5
0% by weight of the sealing composition. 16. An encapsulating composition according to any one of claims 13 to 15, and a plurality of target members sealed by the encapsulating composition. The feature is a bonded body. 17. An electrochemical device comprising an electrochemical cell having an airtight solid electrolyte, an anode and a cathode, and another member whose airtightness is to be maintained between the electrochemical cell and the electrochemical cell. It is provided with a sealing composition for sealing the electrochemical cell and the other member, and the sealing composition contains 5 to 5% of SrO.
20 wt%, CaO 35-45 wt%, Y ₂ O ₃ 2
˜15 wt% and Al ₂ O ₃ 40-50 wt%, Electrochemical device.