JP4873291B2 - Method for producing high-strength oxide ion conductor - Google Patents

Description

  The present invention relates to a method for producing a high-strength oxide ion conductor, particularly a single-phase high-strength oxide ion conductor with few impurity phases.

Oxide ion conductors are generally known to be used in electrolytes or air electrodes of solid oxide fuel cells, gas sensors such as oxygen sensors, oxygen separation membranes such as electrochemical oxygen pumps, etc. The ionic conductor is
Ln: one or more of rare earth elements such as La, Ce, Pr, Nd, Sm,
A: One or more of Sr, Ca and Ba,
B1: One or more of Mg, Al, and In,
B2: one or more of Co, Fe, Ni and Cu,
When the general _{formula: Ln 1-X A X Ga} 1-YZ B1 Y B2 Z O 3 ( provided that, X = 0.05~0.3, Y = 0~0.29 , Z = 0.01~0 .3, Y + Z = 0.025 to 0.3).
Among the oxide ion conductors represented by these general formulas, a general formula: La _1-X Sr _X Ga _1-YZ Mg _Y B 2 _Z O ₃ (wherein B 2 = Co, Fe, Ni, Cu, one type) Or two or more, lanthanum gallate system represented by X = 0.05 to 0.3, Y = 0 to 0.29, Z = 0.01 to 0.3, Y + Z = 0.025 to 0.3) An oxide ion conductor is widely used as a solid electrolyte constituting a power generation cell of a low-temperature type solid oxide fuel cell. Among these, La _1-X Sr _X Ga _1-YZ Mg _Y Co _Z where B2 = Co is used. Lanthanum gallate represented by O ₃ (wherein X = 0.05 to 0.3, Y = 0 to 0.29, Z = 0.01 to 0.3, Y + Z = 0.025 to 0.3) Oxide oxide conductors are used as solid electrolytes constituting power generation cells of low-temperature type solid oxide fuel cells . The _{La 1-X Sr X Ga 1} -YZ Mg Y Co Z O 3 ( where, X = 0.05~0.3, Y = 0~0.29 , Z = 0.01~0.3, Y + Z = among lanthanum gallate-based oxide ion conductor represented by 0.025~0.3) _{(La 0.8} Sr _0.2) is _{(Ga 0.8 Mg 0.15 Co 0.05)} O 3 It is most widely used as an electrolyte constituting a power generation cell of a solid electrolyte fuel cell.

General formula: Ln _1-X A _X Ga _1-YZ B1 _Y B2 _Z O ₃ (where X = 0.05 to 0.3, Y = 0 to 0.29, Z = 0.01 to 0.3) , Y + Z = 0.025 to 0.3), the oxide ion conductor thin plate is made of Ln oxide powder, A carbonate powder, Ga oxide powder, and B1 oxide as raw material powder. A powder and an oxide powder of B2 are prepared, these raw material powders are mixed, calcined and then pulverized to obtain Ln _1-X A _X Ga _1-YZ B1 _Y B2 _Z O ₃ (where X = 0.05) To 0.3, Y = 0 to 0.29, Z = 0.01 to 0.3, and Y + Z = 0.025 to 0.3). The ion conductor powder is formed into a film by a doctor blade method and dried to produce a green body film, and the obtained green body film is sintered to obtain an oxide ion. A thin plate of a conductor was produced.
Accordingly, in order to produce a thin plate of an oxide ion conductor made of (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _0.15 Co _0.05 ) O ₃ , La ₂ O is used as a raw material powder. ₃ powders, SrCO ₃ powders, Ga ₂ O ₃ powders, MgO powders, CoO powders are prepared, these raw material powders are mixed and calcined (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _{0 .15} Co _0.05 ) O ₃ powder was prepared, and this (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _0.15 Co _0.05 ) O ₃ powder was deposited by the doctor blade method. A green body film is produced by drying, and the obtained green body film is sintered to obtain (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _0.15 Co _0.05 ) O ₃ . A thin plate was produced (see Patent Document 1).
Japanese Patent Laid-Open No. 11-335164

The structure of a thin plate of an oxide ion conductor produced by such a conventional method, for example, a thin plate of (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _0.15 Co _0.05 ) O ₃ is ( La _0.8 Sr _0.2 ) (Ga _0.8 Mg _0.15 Co _0.05 ) O ₃ has a large crystal grain size of about 10 μm, and is larger in the grain boundaries and in the grains of the master crystal grain. 2, an impurity phase such as (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _0.15 Co _0.05 ) O ₃ or LaSrGa ₃ O ₇ having a composition shift, as shown in the structural diagram of FIG. (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _0.15 Co) having a structure in which a large number of grains are dispersed and this impurity phase is generated and has a large grain size. _0.05 ) O ₃ thin plate is not strong enough.
In recent years, when the oxide ion conductor is used as an electrolyte of a solid electrolyte fuel cell, the oxide ion conductor is formed into a thinner plate, and the thinner oxide ion conductor. In many cases, the above-mentioned plate is used as an electrolyte of a solid oxide fuel cell. However, the above-described conventional oxide ions have a large mother crystal grain size and a large amount of impurity phase grains are formed in the grain boundaries and grains of the mother crystal grains. When a conductor is formed to be thinner and used as an electrolyte of a solid oxide fuel cell, there is a problem that it is difficult to handle due to its low strength.

In view of the above, the present inventors made a higher strength oxide ion conductor, and formed this high strength oxide ion conductor into a thinner plate to produce a solid electrolyte fuel. Research was conducted to use it as an electrolyte for batteries. as a result,
(A) Mixing ethylene glycol and water as raw materials with ethylene glycol and water to produce a mixed solution (hereinafter, this mixed solution is referred to as mixed solution A), and further dissolving lanthanum acetate, strontium acetate, magnesium acetate and cobalt acetate in water. The mixed solution (hereinafter, this mixed solution is referred to as “mixed solution B”), this mixed solution A and the mixed solution B are further mixed to prepare a mixed solution, and this mixed solution is heated to dehydrate and further crystallized water. Is heated until it evaporates into oxide powder (hereinafter, this heating is referred to as dehydration calcination). Finer La oxide powder, Sr oxide powder, Ga oxide powder, Mg oxide powder and Co oxide powder Aggregated powder or LaSrGaMgCo oxide powder is produced, and the aggregated powder or LaSr of the oxide powder obtained by dehydration calcining The aMgCo oxide powder to prepare a green film by forming dried by a doctor blade method, the obtained green film was obtained by sintering _{(La 0.8 Sr} 0.2) _(Ga The thin plate of _0.8 Mg _0.15 Co _0.05 ) O _{3 corresponds to} the thin plate of (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _0.15 Co _0.05 ) O ₃ in FIG. As shown in the schematic diagram showing the structure, the mother crystal grain size has a fine grain size that is half or less than the conventional mother crystal grain size, and the impurity phase is not generated or generated Because there are very few grain boundary cracks, a high-strength oxide ion conductor thin plate can be obtained, which can be used to produce a higher-strength electrolyte plate.
(B) General formula prepared by the method described in (a): Ln _1-X A _X Ga _1-YZ B1 _Y B2 _Z O ₃ (where X = 0.05 to 0.3, Y = 0 to 0 .29, Z = 0.01~0.3, oxide ion conductor represented by Y + Z = 0.025~0.3), the general _{formula: La 1-X Sr X Ga} 1-YZ Mg Y B2 Z O ₃ (wherein B2 = Co, Fe, Ni, Cu, one or more, X = 0.05 to 0.3, Y = 0 to 0.29, Z = 0.01 to 0.3) , Y + Z = 0.025 to 0.3), and a lanthanum gallate-based oxide ion conductor and a general formula: La _1-X Sr _X Ga _1-YZ Mg _Y Co _Z O ₃ (where X = 0.05-0.3, Y = 0-0.29, Z = 0.01-0.3, Y + Z = 0.025-0.3) Similar effect With, is the research results that were obtained.

The present invention has been made based on the results of such research,
(1) Ln: one or more of rare earth elements such as La, Ce, Pr, Nd, Sm,
A: One or more of Sr, Ca and Ba,
B1: One or more of Mg, Al, and In,
B2: one or more of Co, Fe, Ni and Cu,
Then, ethylene glycol and water are mixed with gallium nitrate to prepare a gallium nitrate solution, and further, acetate obtained by dissolving Ln acetate, A acetate, B1 acetate and B2 acetate in water. A solution is prepared, the nitrate solution and the acetate solution are mixed to prepare a mixed solution, and this mixed solution is dehydrated and calcined to obtain fine Ln oxide powder, A oxide powder, Ga oxide powder, B1 An aggregate powder or LnAGaB1B2 oxide powder in which oxide powder and B2 oxide powder are aggregated is prepared, and the aggregate powder or LnAGaB1B2 oxide powder obtained by dehydration calcining is formed by a doctor blade method. A method for producing a high-strength oxide ion conductor for producing a green body film by film-forming and drying, and sintering the obtained green body film,
(2) A gallium nitrate solution is prepared by mixing ethylene glycol and water with gallium nitrate, and further an acetate solution is prepared by dissolving lanthanum acetate, strontium acetate, magnesium acetate and B2 acetate in water. A mixed solution is prepared by mixing a nitrate solution and an acetate solution, and the mixed solution is dehydrated and calcined to obtain fine La oxide powder, Sr oxide powder, Ga oxide powder, Mg oxide powder and B1 oxidation. An aggregate powder or LaSrGaMgB2 oxide powder in which product powder is aggregated is prepared, and the aggregate powder or LaSrGaMgB2 oxide powder of the oxide powder obtained by dehydration calcining is formed by a doctor blade method and dried. A method for producing a high-strength oxide ion conductor for producing a green body film and sintering the obtained green body film,
(3) A gallium nitrate solution is prepared by mixing ethylene glycol and water with gallium nitrate, and further an acetate solution is prepared by dissolving lanthanum acetate, strontium acetate, magnesium acetate and cobalt acetate in water. A mixed solution is prepared by mixing the solution with an acetate solution, and the mixed solution is dehydrated and calcined to obtain fine La oxide powder, Sr oxide powder, Ga oxide powder, Mg oxide powder, and Co oxide powder. An aggregate powder or a LaSrGaMgCo oxide powder in which the particles are aggregated is produced, and the aggregate powder of the oxide powder or LaSrGaMgCo oxide powder obtained by dehydration and calcination is formed into a film by a doctor blade method and dried to obtain a green body. A high-strength oxide ion transfer characterized by producing a film and sintering the resulting green body film Method for producing a body, and it has the characteristics to.

The present invention includes a power generation cell for a solid oxide fuel cell produced by incorporating an oxide ion conductor produced by the method described in (1), (2) or (3) above. Therefore, the present invention
(4) An electrolyte comprising an oxide ion conductor produced by the method described in (1), (2) or (3) above, and a porous air electrode formed on one surface of the electrolyte, and the other surface This is characterized by a power generation cell for a solid oxide fuel cell in which a porous fuel electrode is formed.

Furthermore, the present invention includes a solid oxide fuel cell in which the power generation cell for a solid oxide fuel cell described in the above (4) is incorporated. Therefore, the present invention
(5) The present invention is characterized by a solid electrolyte fuel cell incorporating the power generation cell for a solid oxide fuel cell according to (4).

  The dehydration calcining performed in the method for producing a high-strength oxide ion conductor according to the present invention is performed under an oxidizing atmosphere such as an air atmosphere at a temperature of 800 to 1200 ° C., and further obtained by a doctor blade. The green sheet is sintered in an oxidizing atmosphere such as an air atmosphere at a temperature of 1200 to 1600 ° C.

  The oxide ion conductor produced by the method of the present invention has an average particle size of the mother crystal of 1 to 5 μm and a fine particle size that is less than half that of the prior art, and the impurity phase does not form in the substrate or Even if it is generated, it is extremely small, so that there are few intergranular cracks. Therefore, the high strength of the oxide ion conductor sheet is improved.

Example 1
Gallium nitrate and ethylene glycol and water are mixed in a ratio of gallium nitrate: 45% by mass, ethylene glycol: 5% by mass, and the balance: water to prepare a gallium nitrate solution. Further, lanthanum acetate, strontium acetate, Magnesium acetate and cobalt acetate are dissolved in water to prepare an acetate solution comprising lanthanum acetate: 28% by mass, strontium acetate: 13% by mass, magnesium acetate: 5% by mass, cobalt acetate: 2% by mass, and the balance: water. The nitrate solution and the acetate solution are mixed to prepare a mixed solution. The mixed solution is heated and held at a temperature of 1000 ° C. for 6 hours for dehydration calcining, fine La oxide powder, and Sr oxidation. Powder, Ga oxide powder, Mg oxide powder and Co oxide powder aggregate powder or LaSrGaMgCo acid To produce an object powder.
The aggregate powder of the oxide powder or LaSrGaMgCo oxide powder obtained by dehydration calcining is mixed with an organic binder solution in which polyvinyl butyral and N-dioctyl phthalate are dissolved in a toluene-ethanol mixed solvent to form a slurry. A green body film was produced in a thin plate shape by a blade method, and the obtained green body film was heated and held in air at 1450 ° C. for 6 hours to sinter, thereby having a thickness of 200 μm and (La _{0.8 sr 0.2) (Ga 0.8 Mg 0.15} Co 0.05) and forming the oxide ion conductor sheet having a composition represented by _{O 3,} embodying the present invention method 1.
Observe the structure of the oxide ion conductor thin plate produced by the method 1 of the present invention, determine the average particle size of the mother crystal, further determine the number of impurity phase grains dispersed in the 50 μm × 50 μm substrate, The results are shown in Table 1. Further, the bending strength of the oxide ion conductor thin plate produced by the method 1 of the present invention was measured by the method defined in JIS R1601, and the results are shown in Table 1.

Conventional Example 1
Average particle size: 10 μm lanthanum oxide powder, average particle size: 1.0 μm strontium carbonate powder, average particle size: 1.0 μm gallium oxide powder, average particle size: 0.2 μm magnesium oxide powder, average particle size: A cobalt oxide powder of 1.0 μm was prepared, and these raw material powders were lanthanum oxide powder: 53.3 mass%, strontium carbonate powder: 12.1 mass%, gallium oxide powder: 30.7 mass%, magnesium oxide powder: 2 0.5% by mass, cobalt oxide powder: Weighed to 1.5% by mass, mixed with a ball mill, and then calcined in air at 1300 ° C. for 3 hours. The bulk calcined body obtained by this calcining treatment was coarsely pulverized with a hammer mill and then finely pulverized with a ball mill to produce a lanthanum gallate electrolyte raw material powder. The obtained lanthanum gallate electrolyte raw material powder is mixed with an organic binder solution in which polyvinyl butyral and N-dioctyl phthalate are dissolved in a toluene-ethanol mixed solvent to form a slurry, and a green body film is prepared in a thin plate shape by the doctor blade method. The obtained green body film was heated and held in air at 1450 ° C. for 4 hours to sinter, thereby having a thickness of 200 μm and (La _0.8 Sr _0.2 ) (Ga _0.8 Mg ₀ An oxide ion conductor thin plate having a composition represented by _.15 Co _0.05 ) O ₃ was prepared and the conventional method 1 was carried out.
The structure of the oxide ion conductor thin plate produced by the conventional method 1 is observed, the average particle size of the mother crystal is obtained, and the number of impurity phase grains dispersed in the 50 μm × 50 μm substrate is obtained. The results are shown in Table 1. Furthermore, the bending strength of the oxide ion conductor thin plate obtained by the conventional method 1 was measured by the method prescribed in JIS R1601, and the results are shown in Table 1.

From the results shown in Table 1, the oxide ion conductor thin plate obtained by the method 1 of the present invention has a smaller average grain size of the mother crystal than the oxide ion conductor thin plate obtained by the conventional method 1. The number of impurity phase grains is small, and the oxide ion conductor thin plate obtained by the method 1 of the present invention is significantly superior in strength to the oxide ion conductor thin plate obtained by the conventional method 1. I understand.

Example 2
Gallium nitrate and ethylene glycol and water are mixed in a ratio of gallium nitrate: 45% by mass, ethylene glycol: 5% by mass, and the balance: water to prepare a gallium nitrate solution. Further, lanthanum acetate, strontium acetate, Magnesium acetate and nickel acetate tetrahydrate dissolved in water, lanthanum acetate: 28% by mass, strontium acetate: 13% by mass, magnesium acetate: 5% by mass, nickel acetate tetrahydrate: 2% by mass, balance: water A mixed solution is prepared by mixing the nitrate solution and the acetate solution. The mixed solution is heated and held at a temperature of 1000 ° C. for 6 hours, and then dehydrated and calcined. La oxide powder, Sr oxide powder, Ga oxide powder, Mg oxide powder and aggregated powder of Ni oxide powder or LaS It was prepared GaMgNi oxide powder.
The aggregate powder or LaSrGaMgNi oxide powder obtained by dehydration calcining is mixed with an organic binder solution in which polyvinyl butyral and N-dioctyl phthalate are dissolved in a toluene-ethanol mixed solvent to form a slurry. A green body film was produced in a thin plate shape by a blade method, and the obtained green body film was heated and held in air at 1450 ° C. for 6 hours to sinter, thereby having a thickness of 200 μm and (La _0.8 An oxide ion conductor thin plate having a composition represented by Sr _0.2 ) (Ga _0.8 Mg _0.15 Ni _0.05 ) O ₃ was produced, and the present method 2 was carried out.
Observe the structure of the oxide ion conductor thin plate prepared by the method 2 of the present invention, determine the average particle size of the mother crystal, further determine the number of impurity phase grains dispersed in the 50 μm × 50 μm substrate, The results are shown in Table 2. Further, the bending strength of the obtained oxide ion conductor thin plate produced by the method 2 of the present invention was measured by the method defined in JIS R1601, and the results are shown in Table 2.

Conventional example 2
Average particle size: 10 μm lanthanum oxide powder, average particle size: 1.0 μm strontium carbonate powder, average particle size: 1.0 μm gallium oxide powder, average particle size: 0.2 μm magnesium oxide powder, average particle size: A nickel oxide powder of 1.0 μm is prepared, and these raw material powders are lanthanum oxide powder: 53.3 mass%, strontium carbonate powder: 12.1 mass%, gallium oxide powder: 30.7 mass%, magnesium oxide powder: 2 0.5% by mass, nickel oxide powder: Weighed to 1.5% by mass, mixed with a ball mill, and then calcined in air at 1300 ° C. for 3 hours. The bulk calcined body obtained by this calcining treatment was coarsely pulverized with a hammer mill and then finely pulverized with a ball mill to produce a lanthanum gallate electrolyte raw material powder. The obtained lanthanum gallate electrolyte raw material powder is mixed with an organic binder solution in which polyvinyl butyral and N-dioctyl phthalate are dissolved in a toluene-ethanol mixed solvent to form a slurry, and a green body film is prepared in a thin plate shape by the doctor blade method. The obtained green body film was heated and held in air at 1450 ° C. for 4 hours to sinter, thereby having a thickness of 200 μm and (La _0.8 Sr _0.2 ) (Ga _0.8 Mg _{0 .15} Ni _0.05 ) O ₃ was prepared as an oxide ion conductor thin plate, and the conventional method 2 was carried out.
The structure of the oxide ion conductor thin plate produced by the conventional method 2 is observed, the average particle size of the mother crystal is obtained, and the number of impurity phase grains dispersed in the 50 μm × 50 μm substrate is obtained. The results are shown in Table 2. Further, the bending strength of the oxide ion conductor thin plate obtained by the conventional method 2 was measured by the method defined in JIS R1601, and the results are shown in Table 2.

From the results shown in Table 2, the oxide ion conductor thin plate obtained by the method 2 of the present invention has an average particle size of the mother crystal smaller than that of the oxide ion conductor thin plate obtained by the conventional method 2. The number of impurity phase grains is small, and the oxide ion conductor thin plate obtained by the method 2 of the present invention is significantly superior in strength to the oxide ion conductor thin plate obtained by the conventional method 2. I understand.

Example 3
Gallium nitrate and ethylene glycol and water are mixed in a ratio of gallium nitrate: 45% by mass, ethylene glycol: 5% by mass, and the balance: water to prepare a gallium nitrate solution. Further, lanthanum acetate, strontium acetate, Magnesium acetate and cuprous acetate dissolved in water, lanthanum acetate: 28% by mass, strontium acetate: 13% by mass, magnesium acetate: 5% by mass, cuprous acetate: 2% by mass, balance: water acetate A solution is prepared, and the nitrate solution and the acetate solution are mixed to prepare a mixed solution. The mixed solution is heated and held at a temperature of 1000 ° C. for 6 hours for dehydration and calcining, and fine La oxide Powder, Sr oxide powder, Ga oxide powder, Mg oxide powder and aggregated powder of Cu oxide powder or LaSrGaMgCu oxide To prepare the end.
The aggregate powder of the oxide powder obtained by dehydration calcining is mixed with an organic binder solution in which polyvinyl butyral and N-dioctyl phthalate are dissolved in a toluene-ethanol mixed solvent to form a slurry, which is formed into a thin plate by a doctor blade method. A green body film was prepared, and the obtained green body film was heated and sintered in air at 1450 ° C. for 6 hours to have a thickness of 200 μm and (La _0.8 Sr _0.2 ) An oxide ion conductor thin plate having a composition represented by (Ga _0.8 Mg _0.15 Cu _0.05 ) O ₃ was prepared, and the present invention method 3 was carried out.
Observe the structure of the oxide ion conductor thin plate produced by the method 3 of the present invention, determine the average particle size of the mother crystal, further determine the number of impurity phase grains dispersed in the 50 μm × 50 μm substrate, The results are shown in Table 3. Further, the bending strength of the obtained oxide ion conductor thin plate produced by the method 3 of the present invention was measured by the method defined in JIS R1601, and the results are shown in Table 3.

Conventional example 3
Average particle size: 10 μm lanthanum oxide powder, average particle size: 1.0 μm strontium carbonate powder, average particle size: 1.0 μm gallium oxide powder, average particle size: 0.2 μm magnesium oxide powder, average particle size: A 1.0 μm copper oxide powder was prepared, and these raw material powders were lanthanum oxide powder: 53.3 mass%, strontium carbonate powder: 12.1 mass%, gallium oxide powder: 30.7 mass%, magnesium oxide powder: 2 0.5% by mass, copper oxide powder: Weighed so as to be 1.5% by mass, mixed with a ball mill, and then calcined in air at 1300 ° C. for 3 hours. The bulk calcined body obtained by this calcining treatment was coarsely pulverized with a hammer mill and then finely pulverized with a ball mill to produce a lanthanum gallate electrolyte raw material powder. The obtained lanthanum gallate electrolyte raw material powder is mixed with an organic binder solution in which polyvinyl butyral and N-dioctyl phthalate are dissolved in a toluene-ethanol mixed solvent to form a slurry, and a green body film is prepared in a thin plate shape by the doctor blade method. The obtained green body film was heated and held in air at 1450 ° C. for 4 hours to sinter, thereby having a thickness of 200 μm and (La _0.8 Sr _0.2 ) (Ga _0.8 Mg ₀ An oxide ion conductor thin plate having a composition represented by _.15 Cu _0.05 ) O ₃ was prepared and the conventional method 3 was performed.
The structure of the oxide ion conductor thin plate produced by the conventional method 3 is observed, the average grain size of the mother crystal is obtained, and the number of impurity phase grains dispersed in the 50 μm × 50 μm substrate is obtained. The results are shown in Table 3. Further, the bending strength of the oxide ion conductor thin plate obtained by the conventional method 3 was measured by the method defined in JIS R1601, and the results are shown in Table 3.

From the results shown in Table 3, the average particle diameter of the mother crystal of the oxide ion conductor thin plate obtained by the method 3 of the present invention is finer than that of the oxide ion conductor thin plate obtained by the conventional method 3. The number of impurity phase grains is small, and the oxide ion conductor thin plate obtained by the method 3 of the present invention is significantly superior in strength to the oxide ion conductor thin plate obtained by the conventional method 3. I understand.

Example 4
Gallium nitrate and ethylene glycol and water are mixed in a ratio of gallium nitrate: 45% by mass, ethylene glycol: 5% by mass, and the balance: water to prepare a gallium nitrate solution. Further, lanthanum acetate, strontium acetate, Magnesium acetate and ferrous acetate dissolved in water, lanthanum acetate: 28% by mass, strontium acetate: 13% by mass, magnesium acetate: 5% by mass, ferrous acetate: 2% by mass, balance: water acetate A solution is prepared, and the nitrate solution and the acetate solution are mixed to prepare a mixed solution. The mixed solution is heated and held at a temperature of 1000 ° C. for 6 hours for dehydration and calcining, and fine La oxide Powder, Sr oxide powder, Ga oxide powder, Mg oxide powder and aggregated powder of Fe oxide powder or LaSrGaMgFe oxide To prepare the end.
The aggregate powder of the oxide powder obtained by dehydration calcining is mixed with an organic binder solution in which polyvinyl butyral and N-dioctyl phthalate are dissolved in a toluene-ethanol mixed solvent to form a slurry, which is formed into a thin plate by a doctor blade method. A green body film was prepared, and the obtained green body film was heated and sintered in air at 1450 ° C. for 6 hours to have a thickness of 200 μm and (La _0.8 Sr _0.2 ) An oxide ion conductor thin plate having a composition represented by (Ga _0.8 Mg _0.15 Fe _0.05 ) O ₃ was prepared, and the present invention method 4 was carried out.
Observe the structure of the oxide ion conductor thin plate produced by the method 4 of the present invention, determine the average particle size of the mother crystal, further determine the number of impurity phase grains dispersed in the 50 μm × 50 μm substrate, The results are shown in Table 4. Further, the bending strength of the obtained oxide ion conductor thin plate produced by the method 4 of the present invention was measured by the method defined in JIS R1601, and the results are shown in Table 4.

Conventional example 4
Average particle size: 10 μm lanthanum oxide powder, average particle size: 1.0 μm strontium carbonate powder, average particle size: 1.0 μm gallium oxide powder, average particle size: 0.2 μm magnesium oxide powder, average particle size: 1.0 μm iron oxide powder is prepared, and these raw material powders are lanthanum oxide powder: 53.3 mass%, strontium carbonate powder: 12.1 mass%, gallium oxide powder: 30.7 mass%, magnesium oxide powder: 2 0.5% by mass, iron oxide powder: Weighed to 1.5% by mass, mixed with a ball mill, and then calcined in air at 1300 ° C. for 3 hours. The bulk calcined body obtained by this calcining treatment was coarsely pulverized with a hammer mill and then finely pulverized with a ball mill to produce a lanthanum gallate electrolyte raw material powder. The obtained lanthanum gallate electrolyte raw material powder is mixed with an organic binder solution in which polyvinyl butyral and N-dioctyl phthalate are dissolved in a toluene-ethanol mixed solvent to form a slurry, and a green body film is prepared in a thin plate shape by the doctor blade method. The obtained green body film was heated and held in air at 1450 ° C. for 4 hours to sinter, thereby having a thickness of 200 μm and (La _0.8 Sr _0.2 ) (Ga _0.8 Mg ₀ An oxide ion conductor thin plate having a composition represented by _.15 Fe _0.05 ) O ₃ was prepared, and the conventional method 4 was performed.
The structure of the oxide ion conductor thin plate produced by the conventional method 4 is observed, the average particle size of the mother crystal is obtained, and the number of impurity phase grains dispersed in the 50 μm × 50 μm substrate is obtained. The results are shown in Table 4. Furthermore, the bending strength of the oxide ion conductor thin plate obtained by the conventional method 4 was measured by the method prescribed in JIS R1601, and the results are shown in Table 4.

From the results shown in Table 4, the average particle diameter of the mother crystal of the oxide ion conductor thin plate obtained by the method 4 of the present invention is smaller than that of the oxide ion conductor thin plate obtained by the conventional method 4. The number of impurity phase grains is small, and the oxide ion conductor thin plate obtained by the method 4 of the present invention is significantly superior in strength to the oxide ion conductor thin plate obtained by the conventional method 4. I understand.

It is explanatory drawing which shows the structure | tissue of the oxide ion conductor thin plate obtained by the method of this invention. It is explanatory drawing which shows the structure | tissue of the oxide ion conductor thin plate obtained by the conventional method.

Claims (3)

Ln: one or more of rare earth elements such as La, Ce, Pr, Nd, Sm,
A: One or more of Sr, Ca and Ba,
B1: One or more of Mg, Al, and In,
B2: one or more of Co, Fe, Ni and Cu,
Then, ethylene glycol and water are mixed with gallium nitrate to prepare a gallium nitrate solution, and further, acetate obtained by dissolving Ln acetate, A acetate, B1 acetate and B2 acetate in water. A solution is prepared, and a mixed solution is prepared by mixing the gallium nitrate solution and the acetate solution. The mixed solution is heated and dehydrated, and further calcined (hereinafter referred to as dehydrated calcining), thereby producing fine Ln. Oxide powder obtained by preparing an aggregate powder or LnAGaB1B2 oxide powder in which oxide powder, A oxide powder, Ga oxide powder, B1 oxide powder and B2 oxide powder are aggregated, and dehydrating and calcining this powder A green body film is prepared by forming an aggregate powder or LnAGaB1B2 oxide powder by a doctor blade method and drying it, and sintering the obtained green body film Method for producing a high-strength oxide ion conductor, wherein the door, B2: Assuming that one or more of Co, Fe, Ni, and Cu are used, a gallium nitrate solution is prepared by mixing ethylene glycol and water with gallium nitrate, and further lanthanum acetate, strontium acetate, magnesium acetate And B2 acetate solution in water is prepared, this nitrate solution and acetate solution are mixed to prepare a mixed solution, and this mixed solution is heated and dehydrated and calcined to obtain fine La Oxide powder obtained by preparing aggregate powder or LaSrGaMgB2 oxide powder in which oxide powder, Sr oxide powder, Ga oxide powder, Mg oxide powder and B2 oxide powder are assembled, and dehydrating and calcining this powder A green body film is obtained by forming a film of an Ag powder or LaSrGaMgB2 oxide powder by the doctor blade method and drying it. Method for producing a high-strength oxide-ion conductor, characterized in sintering the green body film, A gallium nitrate solution is prepared by mixing ethylene glycol and water with gallium nitrate, and then an acetate solution in which lanthanum acetate, strontium acetate, magnesium acetate and cobalt acetate are dissolved in water is prepared. A mixed solution is prepared by mixing the solution, and the mixed solution is heated and dehydrated and calcined to obtain fine La oxide powder, Sr oxide powder, Ga oxide powder, Mg oxide powder and Co oxide powder. An aggregate powder or an LaSrGaMgCo oxide powder in which the particles are aggregated is produced, and the aggregate powder of the oxide powder or LaSrGaMgCo oxide powder obtained by dehydration and calcination is formed into a film by a doctor blade method and dried to obtain a green body. A high-strength oxide ion characterized by producing a film and sintering the obtained green body film Method for producing a conductor.





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