Setter, method for producing setter, and method for producing lithium ion conductive sheet

Abstract

To provide a setter which can be repeatedly used for firing a green sheet containing lithium even if alumina is contained in a main surface, and to provide a method for manufacturing the setter and a method for manufacturing a lithium ion conductive sheet.SOLUTION: A method for manufacturing a setter includes a step of baking a powder on a principal plane of a setter substrate by firing the powder dispersed on the principal plane, wherein the powder contains lithium lanthanum titanate, the content of alumina in the principal plane is 90 mass% or more, and the amount of the powder dispersed on the principal plane is 0. 004g / cm2 or more and 0. 1g / cm2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a setter, a method for manufacturing a setter, and a method for manufacturing a lithium ion conductive sheet. [Background technology]

[0002] Lithium (Li) is widely used as a material for secondary batteries in, for example, portable devices, vehicles, etc. In addition to methods for extracting lithium from ores, methods for recovering lithium from liquids such as seawater include the latter method, which utilizes, for example, a sheet formed from a sintered body capable of conducting lithium ions.

[0003] The following Patent Document 1 discloses a method for producing a lithium-lanthanum-titanium oxide sintered body, which is a sintered body capable of conducting lithium ions. In the method, a mixed powder material is subjected to a calcination step, a pulverization step, a molding step, and a sintering step in this order. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-24725 Summary of the Invention [Problem to be solved by the invention]

[0005] When producing a flat sintered body by the sintering process disclosed in Patent Document 1, a pre-sintered compact (green sheet) is typically placed flat on a refractory material (setter) and fired. Here, an alumina setter is used as the refractory material from the viewpoint of cost, etc. However, when a lithium-containing green sheet is placed on an alumina setter and fired, the surface of the setter rapidly deteriorates, resulting in a problem that the setter cannot be used repeatedly.

[0006] An object of one aspect of the present disclosure is to provide a setter that can be repeatedly used to fire lithium-containing green sheets even if it contains alumina on its main surface, a method for manufacturing the same, and a method for manufacturing a lithium ion conductive sheet. [Means for solving the problem]

[0007] One aspect of the present disclosure provides a setter according to the following items [1] to

[12] , a method for producing the same, or a method for producing a lithium ion conductive sheet. [1] A method for producing a setter substrate, comprising a step of baking powder dispersed on a main surface of the setter substrate to the main surface, the powder containing lanthanum lithium titanate, an alumina content in the main surface being 90 mass % or more, and an amount of the powder dispersed on the main surface being 0.004 g / cm. 2 More than 0.1g / cm 2 The following is a method for manufacturing a setter. [2] The method for producing a setter according to [1], wherein the mass average particle diameter D50 of the powder is 200 μm or less. [3] In the X-ray diffraction pattern of the powder, the maximum peak intensity at a diffraction angle 2θ of 31° or more and 34° or less is defined as intensity I A The maximum peak intensity at a diffraction angle 2θ of 10° or more and 13° or less is defined as intensity I B When the intensity I B / Intensity I A The method for producing a setter according to [1] or [2], wherein is 0.05 or more. [4] In the X-ray diffraction pattern of the powder, the maximum peak intensity at a diffraction angle 2θ of 31° or more and 34° or less is defined as intensity I A The maximum peak intensity at a diffraction angle 2θ of 29 to 31° is defined as intensity I C When the intensity I C / Intensity I A The method for producing a setter according to any one of [1] to [3], wherein is 0.035 or less. [5] The method for producing a setter according to any one of [1] to [4], wherein the content of La2Ti2O7 in the powder is less than 5 mass %. [6] A setter comprising: a ceramic substrate having a main surface containing 90% by mass or more of alumina; and a fired product of lanthanum lithium titanate fixed to the main surface of the ceramic substrate, wherein the fired product has a thickness of 10 μm or more and 300 μm or less. [7] The setter according to [6], wherein the surface roughness of the fired product is 6 μm or more. [8] The setter according to [6] or [7], wherein the standard deviation of the surface roughness of the fired product is 2 μm or less. [9] The setter according to any one of [6] to [8], wherein at least one of a composite oxide of lanthanum and aluminum and a composite oxide of lanthanum, titanium and aluminum is located at the interface between the main surface and the fired product.

[10] A setter comprising a ceramic substrate and an outermost layer covering a main surface of the ceramic substrate and containing 90% by mass or more of alumina, wherein a fired product of lanthanum lithium titanate is fixed to at least a portion of the outermost layer, and the fired product has a thickness of 10 μm or more and 300 μm or less.

[11] The setter according to any one of [6] to

[10] , wherein the setter is a setter for firing a lithium ion conductive sheet.

[12] A method for producing a lithium ion conductive sheet, comprising placing a green sheet on the setter according to any one of [6] to

[11] and firing the green sheet. [Effects of the Invention]

[0008] According to one aspect of the present disclosure, it is possible to provide a setter that can be repeatedly used to fire lithium-containing green sheets even if it contains alumina on its main surface, a method for manufacturing the same, and a method for manufacturing a lithium ion conductive sheet. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a setter according to an embodiment. [Figure 2] FIG. 2 is a diagram for explaining a method for manufacturing a setter according to the embodiment. [Figure 3]FIG. 3 is a schematic cross-sectional view showing a lithium conductive sheet. [Figure 4] FIG. 4(a) is a schematic cross-sectional view showing the state before and after the firing step according to the reference example, and FIG. 4(b) is a schematic cross-sectional view showing the state before and after the firing step according to the embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view showing a setter according to a modified example. [Figure 6] 6(a) and (b) are the X-ray diffraction patterns of LLTO powder A and LLTO powder C, respectively. [Figure 7] 7(a) and (b) are photographs of the setter surfaces before and after the adhesion test for Example 1 and Comparative Example 4, respectively. [Figure 8] 8(a) to 8(c) are photographs of the surfaces of the setters of Example 2 and Comparative Examples 1 and 2 before and after the adhesion test, respectively. [Figure 9] FIG. 9 shows the X-ray diffraction pattern of the sintered mixture of LLTO powder A and setter powder. [Figure 10] FIG. 10 shows the X-ray diffraction pattern of the sintered mixture of LLTO powder C and setter powder. [Figure 11] FIG. 11 is an X-ray diffraction pattern of a measurement sample obtained from the surface of the setter of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present disclosure will be described in detail below, but the present disclosure is not limited thereto.

[0011] <setter>

[0012] FIG. 1 is a schematic cross-sectional view showing a setter according to the present embodiment. The setter 1 shown in FIG. 1 is, for example, a table (jig) on ​​which an object to be fired in an electric furnace or the like (e.g., a substrate such as a green sheet of a ceramic sheet) is placed. In one example, the setter 1 is used as a jig on which a green sheet that serves as the base for a lithium ion conductive sheet and contains lithium is placed (i.e., a setter for a lithium ion conductive sheet). The setter 1 has high heat resistance because it is housed in an electric furnace or the like together with the material. For this reason, the setter 1 may also be referred to as a firing setter. The shape (planar shape) of the setter 1 as viewed in the thickness direction of the setter 1 is, for example, a polygonal shape such as a rectangle, a circle, an ellipse, or the like. The dimension of the setter 1 as viewed in the thickness direction of the setter 1 is, for example, 50 mm or more and 500 mm or less. In one example, when the planar shape of the setter 1 is rectangular, the long side is 50 mm or more and 500 mm or less, and the short side is 50 mm or more and 400 mm or less. From the viewpoints of preventing warping, cost, etc., the thickness of the setter 1 may be 1 mm or more and 100 mm or less, 5 mm or more and 50 mm or less, or 7 mm or more and 30 mm or less. Hereinafter, the view from the thickness direction will also be referred to as a planar view.

[0013] The setter 1 includes a ceramic base 3 and a fired product 5 fixed to a main surface 3a of the ceramic base 3. When an object to be placed, such as a green sheet, is placed on the setter 1, the object is positioned on the fired product 5. That is, when the setter 1 is in use, the main surface 3a and the fired product 5 face upward.

[0014] (ceramic substrate) The ceramic substrate 3 is a ceramic plate-like member that is the main constituent element of the setter 1. The shape of the ceramic substrate 3 is the same as that of the setter 1. The thickness of the ceramic substrate 3 is approximately the same as that of the setter 1. Pores may be provided inside the ceramic substrate 3. In other words, the ceramic substrate 3 may be a porous substrate. The porosity of the ceramic substrate 3 may be, for example, 50% or less. The porosity may be, for example, 0% or more, or 15% or more.

[0015] The ceramic substrate 3 contains a ceramic material as a main material. The ceramic substrate 3 is formed solely from a ceramic material, but is not limited to this. Examples of the ceramic material include aluminum oxide (alumina), silicon oxide (silica), magnesium oxide (magnesia), yttrium oxide (yttria), silicon carbide (SiC), and zirconium oxide (zirconia). The ceramic substrate 3 may be formed from one type of ceramic material or multiple types of ceramic materials. The content of the ceramic material in the ceramic substrate 3 is, for example, 90% by mass or more. In this embodiment, the ceramic substrate 3 is a substrate (alumina substrate) in which the ceramic material is alumina. In this embodiment, the content of alumina in the ceramic substrate 3 is 90% by mass or more. The content may be 95% by mass or more, 99% by mass or more, or 100% by mass.

[0016] The main surface 3a is a portion that can constitute a part of the main surface of the setter 1. The content of the ceramic material in the main surface 3a may be the same as or different from the content of the ceramic material in the ceramic substrate 3. In this embodiment, the alumina content in the main surface 3a is 90 mass% or more. The alumina content in the main surface 3a may be 95 mass% or more, or may be 99 mass% or more. The main surface 3a may contain, for example, impurities and elements contained in the fired product 5. The composition of the main surface 3a can be measured using, for example, X-ray diffraction (XRD) or ICP optical emission spectroscopy (ICP: Inductively Coupled Plasma).

[0017] The main surface 3a may be a flat surface or an uneven surface. In this embodiment, when the surface roughness of the main surface 3a is 0 μm or more and less than 6.0 μm, the main surface 3a is considered to be a flat surface. The surface roughness of the main surface 3a may be 0 μm or more and 5.0 μm or less, or 0 μm or more and 3.5 μm or less. From the viewpoint of uniformity of the surface roughness, the standard deviation of the surface roughness of the main surface 3a is, for example, 0 μm or more and 2.0 μm or less. The standard deviation may be 0 μm or more and 1.0 μm or less, or 0 μm or more and 0.6 μm or less. In this embodiment, the surface roughness of the main surface 3a corresponds to the arithmetic mean roughness Ra of the main surface 3a. The standard deviation SD of the surface roughness of the main surface 3a is calculated, for example, using the following formula, by dividing the sum of the squares of the deviations of each data by the number of data and taking the square root. In the formula, x i is each data, x ave indicates the average of all data, and n indicates the number of samples.

number

[0018] (baked products) The fired product 5 constitutes at least a portion of the main surface of the setter 1 and is fixed to the main surface 3a. In other words, the fired product 5 can be said to be a coating portion of the setter 1. When an object to be placed is placed on the setter 1, the fired product 5 is located between the object to be placed and the ceramic substrate 3. This makes it difficult for the object to come into contact with the ceramic substrate 3. In this specification, fixing the fired product 5 to the setter 1 does not mean that the fired product 5 is simply attached to the setter 1, but that the fired product 5 is in close contact with the setter 1. This makes it difficult for the fired product 5 to peel off from the setter 1 due to friction with the object to be placed, etc.

[0019] In this embodiment, the fired product 5 is formed by firing powder dispersed on the main surface 3a of the ceramic substrate 3 (details will be described later). Therefore, the fired product 5 does not need to have a film shape that covers the entire main surface 3a as shown in FIG. 1 . In other words, the fired product 5 may cover the entire main surface 3a, or may cover only a portion of the main surface 3a. For example, the fired product 5 has a layer shape or a block shape that covers a portion of the main surface 3a. In these cases, a portion of the main surface 3a may be exposed from the fired product 5. Therefore, in this embodiment, the main surface of the setter 1 may be formed by the portion of the main surface 3a and the fired product 5. The proportion of the portion of the main surface 3a exposed from the fired product may be 0% to 50% or 0% to 30% or 0% to 10%. The shape of the fired product 5 in a plan view may be irregular. For example, the shape of the fired product 5 in a plan view may vary from setter to setter.

[0020] When the fired product 5 has a layered shape, it is sufficient that the fired product 5 covers the portion of the ceramic substrate 3 where the green sheets overlap. In this case, the fired product 5 may cover the entire portion or a portion of the portion. When the fired product 5 has a layered shape, voids may be provided inside the fired product 5. That is, the fired product 5 may be a porous layer. When the fired product 5 has a block shape, it is sufficient that the fired product 5 is present in the portion of the ceramic substrate 3 where the green sheets overlap. In this case, the fired product 5 may be present so as to overlap the entire portion or a portion of the portion. When the fired product 5 has a block shape, voids may be provided inside the fired product 5. That is, the fired product 5 may be a porous body. A plurality of layered fired products 5 or a plurality of block-shaped fired products 5 may be present on the main surface 3a. Alternatively, both the fired material 5 having a layer shape and the fired material 5 having a lump shape may be present on the main surface 3a.

[0021] The surface roughness of the fired product 5 is a value measured using, for example, a stylus-type surface roughness measuring instrument (e.g., manufactured by Mitutoyo Corporation, product name: SURFTEST SJ-201). The standard deviation of the surface roughness of the fired product 5 is a value calculated, for example, from the surface roughness at any five points on the fired product 5. The surface roughness (arithmetic mean roughness Ra) of the fired product 5 may be 6 μm or more, 10 μm or more, 15 μm or more, or 80 μm or less. If the surface roughness is 6 μm or more, when a green sheet is placed on the fired product 5 of the setter 1 and fired, the green sheet is less likely to come into contact with the main surface 3a. If the surface roughness is 80 μm or less, the fired product 5 is less likely to fall off due to friction between the setter 1 and the green sheet. As a result, the fired product 5 tends to be less likely to fall off from the setter 1 even when the setter 1 is used repeatedly. The standard deviation of the surface roughness of the fired product 5 may be 2 μm or less. When the standard deviation is 2 μm or less, warping and deformation of the setter 1 may be less likely to occur.

[0022] The thickness of the fired product 5 in this specification is the difference between the height of the main surface 3a of the ceramic substrate 3 and the height of the fired product 5, with the main surface 3a being used as a reference. The thickness of the fired product 5 can be measured using a laser displacement meter by a method described below. In this embodiment, the thickness of the fired product 5 is 10 μm or more and 300 μm or less. The lower limit of the thickness may be 15 μm, 25 μm, or 50 μm. The upper limit of the thickness may be 250 μm, 150 μm, or 100 μm.

[0023] <Measurement of thickness of fired product 5> First, a setter 1 is prepared in which the main surface 3a of the ceramic substrate 3 is exposed. Next, the height is measured by scanning a laser along a path that passes through the area where the main surface 3a is exposed and the area where the fired product 5 is fixed. The measurement conditions are a scan distance of 50,000 μm, a scan speed of 1,000 μm, and a scan pitch of 1 μm. Next, baseline correction is performed on the obtained measurement data. The baseline (reference) used for baseline correction is a straight line obtained using the least squares method from the measurement data of the exposed area of ​​the main surface 3a. The thickness of the fired product 5 is then calculated from the height of the main surface 3a and the height of the fired product 5. The height of the main surface 3a is the average value of 5,000 points arbitrarily selected from the measurement data on the main surface 3a. The height of the fired product 5 is the average value of 20,000 points arbitrarily selected from the measurement data on the fired product 5.

[0024] <Setter manufacturing method> The method for producing a setter according to this embodiment will be described in detail below with reference to Fig. 2. Fig. 2 is a diagram for explaining the method for producing a setter according to this embodiment. First, the setter base material and powder used in the method for producing a setter according to this embodiment will be described.

[0025] (setter substrate) In this embodiment, the setter substrate 20 shown in FIG. 2 corresponds to the ceramic substrate 3 (see FIG. 1) included in the setter 1 described above.

[0026] (powder) The powder 22 corresponds to the raw material of the fired product 5 described above. In this embodiment, as shown in FIG. 2, the fired product 5 is formed by firing the powder 22 dispersed on the main surface 20a of the setter substrate 20. The mass average particle diameter D50 of the powder 22 may be 200 μm or less, 100 μm or less, 75 μm or less, 50 μm or less, or 0.1 μm or more. When the above value is 200 μm or less, the powder 22 is likely to overlap with each other on the main surface 20a of the setter substrate 20. This makes it easier for the powder 22 to bond with each other, and the powder 22 is well fixed to each other. Therefore, when firing an object placed on the setter 1, sintering between the fired product 5 and the object to be placed is unlikely to occur. Therefore, the fired product 5 is unlikely to fall off. When the above value is 0.1 μm or more, the surface roughness of the fired product 5 of the powder 22 is likely to be equal to or greater than a predetermined value. In this case, the fired product 5 is less likely to fall off due to friction between the setter 1 and the green sheet. The mass-average particle diameter D50 in this specification is a value calculated based on the volume distribution of Heywood diameters obtained by analyzing a scanning electron microscope (SEM) image of the particles using image analysis software (such as Macview). This volume distribution of Heywood diameters is obtained by manually surrounding each of 300 independently occurring primary particles in the SEM image.

[0027] The powder 22 in this embodiment is an inorganic powder that does not affect or is unlikely to affect an object (such as a green sheet) placed on the setter 1. For example, even if the object is a lithium conductive sheet and the powder 22 and / or the fired product 5 are fused to the lithium conductive sheet, the performance of the lithium conductive sheet is unlikely to deteriorate. In this embodiment, the powder 22 contains lanthanum lithium titanate as a main component. The content of lanthanum lithium titanate in the powder 22 may be 90% by mass or more, 95% by mass or more, 97% by mass or more, 99% by mass or more, or even 100% by mass. When the content is 90% by mass or more, the fired product 5 is well fixed to the setter substrate 20 and is unlikely to fall off the setter 1. Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 tends to be unlikely to deteriorate. The content may be 100% by mass or less, 99% by mass or less, or 98% by mass or less. The content of lanthanum lithium titanate in the powder 22 can be determined by, for example, X-ray diffraction. The powder 22 may be a material for the object to be placed.

[0028] The powder 22 may or may not contain a composite oxide of lanthanum and titanium. The composite oxide of lanthanum and titanium is, for example, La2Ti2O7. The content of La2Ti2O7 in the powder 22 may be less than 5% by mass, 4.5% by mass or less, 3% by mass or less, 1% by mass or less, or 0% by mass. When the content is less than 5% by mass, the fired product 5 of the powder 22 is well fixed to the setter substrate 20 and is therefore less likely to fall off from the setter 1 (details will be described later). Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 tends to be less likely to deteriorate. The content may be 1% by mass or more, or 2% by mass or more. The content of La2Ti2O7 in the powder 22 can be determined, for example, using X-ray diffraction.

[0029] In addition to lanthanum lithium titanate and lanthanum-titanium composite oxide, the powder 22 may contain various impurities. The impurities may be organic or inorganic. Examples of the impurities include oxides, chlorides, hydroxides, etc. containing at least one of Na, K, Ca, Ba, Pb, Sr, Pr, Nd, Sm, Gd, Dy, Y, Eu, Tb, Ce, Ag, Bi, Mg, Co, Ni, Cu, Cr, Fe, Ga, In, Sc, Ge, Hf, Mn, Sn, Zn, Zr, W, Ru, Nb, Ta, Al, and Si. The impurities may be determined, for example, by ICP emission spectroscopy, or, if necessary, by X-ray diffraction.

[0030] The powder 22 may be a commercially available lanthanum lithium titanate powder, or may be obtained by mixing and reacting the raw materials for the powder 22. The raw materials for the powder 22 contain a lanthanum raw material, a titanium raw material, and a lithium raw material in a predetermined ratio. The mixing and reaction of these raw materials is carried out by pulverizing and mixing the raw materials using, for example, a ball mill. In this case, the raw materials may be calcined simultaneously with mixing, calcined after mixing, or not calcined.

[0031] Lanthanum raw materials are powders primarily composed of lanthanum (La), such as lanthanum oxide, lanthanum carbonate, and lanthanum hydroxide. Lanthanum raw materials may contain a single material or multiple materials. Lanthanum raw materials correspond to materials with the highest lanthanum content. Therefore, lanthanum raw materials may contain elements other than La (e.g., Na, K, Ca, Ba, Si, Pb, Sr, Pr, Nd, Sm, Gd, Dy, Y, Eu, Tb, Ce, Ag, Bi, Mg, Co, Ni, Cu, Cr, Fe, Ga, In, Sc, Ge, Hf, Mn, Sn, Zn, Zr, W, Ru, Nb, Ta, Al, etc.).

[0032] The titanium raw material is a powder mainly composed of titanium (Ti), such as titanium oxide, titanium hydroxide, or various titanates. The titanium raw material may contain a single material or multiple materials. For example, the titanium raw material may contain only titanium oxide, or may contain titanium oxide and titanium hydroxide. The titanium raw material corresponds to the material with the highest titanium content. Therefore, like the lanthanum raw material, the titanium raw material may contain elements other than Ti.

[0033] The lithium raw material is a powder mainly composed of lithium (Li), such as lithium oxide, lithium carbonate, or lithium hydroxide. The lithium raw material may contain a single material or multiple materials. The lithium raw material corresponds to the material with the highest lithium content. Therefore, the lithium raw material may contain elements other than Li, similar to the lanthanum raw material and titanium raw material.

[0034] In the X-ray diffraction pattern obtained by measuring the powder 22 with X-rays, a peak may appear at a diffraction angle 2θ of 10° or more and 13° or less. Here, the maximum peak intensity appearing at a diffraction angle 2θ of 31° or more and 34° or less is referred to as intensity I A The maximum peak intensity appearing at a diffraction angle 2θ of 10° or more and 13° or less is the intensity I B Then, the intensity I B / Intensity I A may be 0.05 or more, 0.1 or more, 0.3 or more, or 1.0 or less. B / Intensity I A When the sintered product 5 of the powder 22 is 0.05 or more, the sintered product 5 of the powder 22 is well fixed to the setter substrate 20. Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 tends not to deteriorate easily.

[0035] In the X-ray diffraction pattern, a peak may appear at a diffraction angle 2θ of 29° or more and 31° or less. When a peak appears at a diffraction angle 2θ of 29° or more and 31° or less in the X-ray diffraction pattern, the maximum peak intensity appearing at a diffraction angle 2θ of 29° or more and 31° or less is referred to as intensity I C In this case, the intensity I C / Intensity I Amay be 0.035 or less, 0.03 or less, 0.01 or less, or 0 or more. A When the strength I is 0.035 or less, the fired product 5 of the powder 22 is well fixed to the setter substrate 20. Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 tends not to deteriorate. C / Intensity I A It can be said that the lower the value, the higher the content of lanthanum lithium titanate in the powder 22.

[0036] The manufacturing method of the setter 1 of this embodiment includes, for example, a step of dispersing and arranging powder 22 on the main surface 20a of the setter substrate 20 (dispersing and arranging step), and a step of firing the setter substrate 20 with the powder 22 dispersed and arranged on the main surface 20a to bake the powder 22 onto the main surface 20a (firing step).

[0037] (Dispersion process) First, the powder 22 is dispersed and allocated on the main surface 20a of the setter substrate 20 (dispersion and allocation step). In this step, as shown in FIG. 3, the powder 22 is dispersed and allocated on the main surface 20a of the setter substrate 20. The powder 22 is dispersed and allocated by a known method. Examples include methods using a sieve, a brush, a roller, a spray, and a printing method. The amount of the powder 22 dispersed and allocated on the main surface 20a of the setter substrate 20 is 0.004 g / cm. 2 More than 0.1g / cm 2 The amount is 0.005 g / cm 2 More than 0.1g / cm 2 Less than 0.007g / cm 2 More than 0.1g / cm 2 The following is also acceptable.

[0038] (Firing process) Next, the setter substrate 20 is fired (firing step). In this step, the setter substrate 20 having the powder 22 dispersed on the main surface 20a is fired, thereby baking the powder 22 onto the main surface 20a. This produces a setter 1 having a ceramic substrate 3 and a fired product 5 fixed to the main surface 3a of the ceramic substrate 3. In the firing step, the powder 22 can bond together. As a result, at least a portion of the fired product 5 becomes coarser than the powder 22.

[0039] The setter substrate 20 is fired by a known method. For example, the setter substrate 20 may be fired using a known heating furnace. The heating furnace may be an electric furnace or a combustion furnace. Examples of the heating furnace include a high-temperature box furnace, a muffle furnace, a shuttle furnace, a tunnel furnace, and an elevator furnace. The heating method may be continuous or batchwise. In this embodiment, the setter substrate 20 is first placed in a heating furnace such as a high-temperature box electric furnace. The setter substrate 20 is placed in the heating furnace with the surface on which the powder 22 is dispersed facing up. The temperature inside the heating furnace is then maintained at a predetermined temperature for a certain period of time. The temperature at which the setter substrate 20 is fired may be 1100°C or higher and 1500°C or lower, or 1250°C or higher and 1400°C or lower. The firing time for the setter substrate 20 may be 2 hours. The firing time refers to the time from when the temperature inside the heating furnace reaches a predetermined temperature to when cooling inside the heating furnace begins. Thereafter, the inside of the heating furnace is cooled until the temperature inside the heating furnace becomes equal to or lower than a certain temperature (for example, room temperature). With the above steps, the heating of the setter substrate 20 and the powder 22 is completed.

[0040] The firing process fixes the fired product 5 to the main surface 3a by fusing the fired product 5 to the main surface 3a as the setter substrate 20 and powder 22 are heated. In this case, some atoms contained in the powder 22 may diffuse into the setter substrate 20, and / or some atoms contained in the setter substrate 20 may diffuse into the powder 22. Some of the diffused atoms may react with other atoms present at the diffusion destination to form a complex oxide. In this case, the fired product 5 is firmly fixed to the main surface 3a via the complex oxide. That is, the complex oxide may be present at the interface between the fired product 5 and the main surface 3a. The presence of the complex oxide at the interface between the fired product 5 and the main surface 3a ensures that the fired product 5 is well fixed to the setter substrate 20 and is less likely to fall off the setter 1. Therefore, the surface of the setter 1 tends to be less susceptible to deterioration, even with repeated use of the setter 1. In the firing step, the atoms diffused from the powder 22 are, for example, at least one of lithium, lanthanum, and titanium. The atoms diffused from the main surface 3a are, for example, aluminum. The composite oxides include, for example, composite oxides obtained by the reaction of lanthanum and aluminum (composite oxide of lanthanum and aluminum), and composite oxides obtained by the reaction of lanthanum, titanium, and aluminum (composite oxide of lanthanum, titanium, and aluminum). Specific examples of composite oxides of lanthanum and aluminum include La 0.92 Al 11.75 O 19 A specific example of a composite oxide of lanthanum, titanium, and aluminum is LaTi2Al9O 19 And so on.

[0041] <Method for manufacturing lithium ion conductive sheet> The method for producing a lithium ion conductive sheet according to this embodiment involves firing a green sheet placed on the setter 1. The method for producing a lithium ion conductive sheet includes, for example, a mixing step of grinding and mixing raw materials to form a mixture, a molding step of molding the mixture without calcining the mixture, and a sheet firing step of placing the molded product on the setter and firing it.

[0042] (Mixing process) First, a mixture that serves as the main raw material for the lithium ion conductive sheet 30 shown in FIG. 3 is formed (mixing step). In this step, raw materials for the metal atoms contained in the lithium ion conductive sheet 30 are pulverized and mixed to form a mixture. Hereinafter, the powder containing the main raw materials will also be referred to as raw material powder. In addition to the metal compound that serves as the main raw material, a sintering aid or the like may be mixed into the mixture. The sintering aid is, for example, boron. A composite oxide containing boron may be mixed into the mixture.

[0043] The raw materials are pulverized and mixed by a known method. For example, the raw materials may be pulverized and mixed using a known mixer / pulverizer. The mixer / pulverizer may be, for example, a medium-flow mixer / pulverizer (a ball mill, a planetary mill, etc.), an agitator mixer / pulverizer (a tower mill, an agitator / calculator mill, a flow pipe mill, etc.), or a mortar (an agate mortar, an alumina mortar, a mortar / mortar masher, etc.). The raw materials may be wet-mixed or dry-mixed. The measured raw materials may be mixed in a mixer such as a container rotary mixer (a horizontal cylinder, an inclined cylinder, a V-type, etc.) or a mechanical agitator mixer (a ribbon, a screw, a rod, etc.), and the mixture may then be pulverized in a mortar or the like.

[0044] In this embodiment, the measured raw materials are wet-mixed in a ball mill. At this time, a solvent is used to disperse the raw materials. In addition, after at least a binder is added during wet mixing, the wet mixing is continued. Therefore, in this embodiment, a mixture is formed by wet-mixing raw material powders, a binder, and a solvent. As a result, a slurry (raw material slurry) containing a pulverized mixture of raw material powders is formed. This raw material slurry is subjected to, for example, a degassing treatment. During the wet mixing, materials other than the raw materials, solvent, and binder may be added. Note that in this embodiment, the solvent and binder are added to the raw materials simultaneously, but this is not limited to this. The solvent and binder, etc. may be added to the raw materials at the same time or at different times. The wet mixing is continued, for example, until all materials contained in the mixture are mixed.

[0045] The type of binder is not particularly limited, and may be appropriately selected from, for example, organic binders and inorganic binders that are known in conventional ceramic sheet manufacturing methods.

[0046] The type of solvent used in the raw material slurry is not particularly limited, and may be appropriately selected from solvents known in conventional ceramic sheet manufacturing methods.

[0047] (molding process) Next, the obtained mixture is molded into a molded product (green sheet) without calcining (molding process). In the molding process, first, a slurry containing the mixture is produced. Then, the slurry is coated on one side of a substrate film. For example, the slurry is coated by a blade coating method, a doctor blade method, or a roll coating method using a die coater or lip coater. Then, the coated slurry is dried and peeled off. For example, the slurry is dried at 100°C for 1 hour. Before peeling off the dried slurry, excess portions may be removed using, for example, a Thomson blade. This process forms a molded product, a green sheet.

[0048] The base film is a resin film such as a polyethylene terephthalate (PET) film. A long green sheet can be formed by using a long base film. The size and thickness of the green sheet can be determined, for example, by taking into consideration the size and thickness of the fired sheet and the shrinkage rate due to firing.

[0049] (Sheet baking process) Next, the obtained molded product is placed on a setter and fired (sheet firing process). In the sheet firing process, the molded product (green sheet) is first placed on the fired product 5 of the setter 1. At this time, it is preferable to place the green sheet so that it is in contact only with the fired product 5 of the setter 1. Next, the green sheet placed on the setter 1 is fired. For example, the green sheet is fired at 1100°C to 1500°C using a known method such as an electric furnace. Here, firing the green sheet in an electric furnace corresponds to maintaining the electric furnace in which the green sheet was fired at a predetermined temperature for a predetermined time. The green sheet is fired, for example, in an air atmosphere or a low-oxygen concentration atmosphere for 10 minutes to 6 hours. This removes organic components such as the binder and solvent, forming a composite oxide sheet. The sheet is then peeled off from the setter 1 to obtain a lithium ion conductive sheet 30.

[0050] The following describes the effects achieved by the setter and the manufacturing method of the setter according to the above embodiment. According to the manufacturing method of the setter 1 according to this embodiment, the powder 22 dispersed on the main surface 20a of the setter substrate 20 is fired, thereby baking the powder 22 onto the main surface 20a. Here, the powder 22 contains lanthanum lithium titanate, and the amount of the powder 22 dispersed on the main surface 20a is 0.004 g / cm. 2 More than 0.1g / cm 2 The setter 1 manufactured by the above manufacturing method includes a fired product 5 fixed to the main surface 3a of the ceramic substrate 3 and composed primarily of lanthanum lithium titanate, and the fired product 5 has a thickness of 10 μm to 300 μm. By using such a setter 1 to fire a green sheet containing lithium, direct contact between the main surface 3a of the ceramic substrate 3 and the green sheet can be suppressed. As a result, changes to the surface of the setter 1 are unlikely to occur, and deterioration of the surface of the setter 1 due to repeated use of the setter 1 is unlikely to occur. The setter is particularly useful when the green sheet is a green sheet of a lithium ion conductive sheet (i.e., when the setter is a setter for firing a lithium ion conductive sheet).

[0051] In one example, the mass median particle diameter D50 of the powder 22 may be 200 μm or less. In this case, the powder 22 is likely to overlap with each other on the main surface 20a of the setter substrate 20.

[0052] In one example, in the X-ray diffraction pattern of the powder 22, the maximum peak intensity at a diffraction angle 2θ of 31° or more and 34° or less is referred to as intensity I A The maximum peak intensity at a diffraction angle 2θ of 10° or more and 13° or less is defined as intensity I B When the intensity I B / Intensity I A may be 0.05 or more. In this case, the content of lanthanum lithium titanate in the powder 22 is equal to or greater than a predetermined value. In this case, the fired product 5 of the powder 22 tends to be well fixed to the setter substrate 20. Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 is less likely to deteriorate.

[0053] In one example, in the X-ray diffraction pattern of the powder 22, the maximum peak intensity at a diffraction angle 2θ of 31° or more and 34° or less is referred to as intensity I A The maximum peak intensity at a diffraction angle 2θ of 29 to 31° is defined as intensity I C When the intensity I C / Intensity I A may be 0.035 or less. In this case, the content of titanium lanthanum lithium in the powder 22 is a predetermined value or less. In this case, the fired product 5 of the powder 22 tends to be well fixed to the setter substrate 20. Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 is less likely to deteriorate.

[0054] For example, the content of La2Ti2O7 in the powder 22 may be less than 5% by mass. In this case, the fired product 5 of the powder 22 is well fixed to the setter substrate 20 and is unlikely to fall off from the setter 1. Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 tends not to deteriorate.

[0055] In one example, the surface roughness of the fired product 5 on the setter 1 may be 6 μm or more. In this case, when a green sheet is placed on the fired product 5 of the setter 1 and fired, the green sheet is less likely to come into contact with the main surface 3 a. Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 is less likely to deteriorate.

[0056] In one example, the standard deviation of the surface roughness of the fired product 5 on the setter 1 may be 2 μm or less. In this case, even if the setter 1 is used repeatedly, warping and deformation of the setter 1 are unlikely to occur.

[0057] In one example, at least one of a composite oxide of lanthanum and aluminum and a composite oxide of lanthanum, titanium, and aluminum may be located at the interface between the main surface 3a of the setter 1 and the fired product 5. In this case, the fired product 5 is well fixed to the main surface 3a, so that the fired product 5 is less likely to fall off. Therefore, even if the setter 1 is used repeatedly, the surface of the setter 1 is less likely to deteriorate. The reason why the above effect is achieved is presumed to be as follows. Hereinafter, the reason why the above effect is achieved will be explained with reference to FIGS. 4(a) and 4(b). FIG. 4(a) is a schematic cross-sectional view showing before and after the firing step according to a reference example, and FIG. 4(b) is a schematic cross-sectional view showing before and after the firing step according to an embodiment. In each of FIGS. 4(a) and 4(b), the view before the arrow shows before the firing step, and the view after the arrow shows after the firing step. In the reference example, the amount of powder 22 dispersed and arranged on the main surface 20a of the setter substrate 20 is 0.004 g / cm. 2 is less than.

[0058] 4(a) and 4(b), when the setter substrate 20 having the powders 22 dispersed therein is fired, not only the powders 22 bond to each other but also fusion between the powders 22 and the setter substrate 20 and volatilization of the components contained in the powders 22 may occur. These components include substances and atoms contained in the powders 22. The lighter the substance or atom, the more easily it volatilizes from the powder 22. In this embodiment, lithium contained in the powders 22 tends to volatilize easily.

[0059] The fusion of the powder 22 and the setter substrate 20 occurs at the interface between the setter substrate 20 and the powder 22. When the powder 22 and the setter substrate 20 fuse together, metal atoms interdiffuse between a portion of the powder 22 and the setter substrate 20. This interdiffusion is thought to produce a composite oxide of lanthanum and aluminum, a composite oxide of lanthanum, titanium, and aluminum, or the like, at the interface between the setter substrate 20 and the fired product. That is, the portion of the fired product (fired product 24) that is not affected by the interdiffusion of metal atoms between the setter substrate 20 and the fired product is thought to be fixed to the setter substrate 20 via the region containing the above-mentioned composite oxide (fused region 26). On the other hand, volatilization of components contained in the powder 22 tends to occur from the exposed surface of the powder 22 dispersed on the setter substrate 20. The powder 22 from which the components have volatilized is transformed into an object (fired product 28) whose surface is covered with a substance containing less of the component. It is presumed that the substance that coats the surface of the fired product 28 inhibits the mutual diffusion of metal atoms that occurs between the fired product 28 and the setter substrate 20. For this reason, it is presumed that the fused region 26 is unlikely to form between the fired product 28 and the setter substrate 20.

[0060] In the firing process of the reference example (see FIG. 4(a)), the amount of powder 22 dispersed on the setter substrate 20 is small. In this case, the powder 22 dispersed on the setter substrate 20 is less likely to overlap with each other, and the proportion of powder 22 with exposed surfaces is increased. Powder 22 with such exposed surfaces tends to be easily transformed into a fired product 28 as the above-mentioned components volatilize. Therefore, powder 22 in contact with the main surface 20a of the setter substrate 20 is more likely to be transformed into a fired product 28 than to form a fused region 26. For this reason, a fused region 26 is less likely to be formed between the setter substrate 20 and the fired product 28. Therefore, it is presumed that the fired product 5 is not well fixed to the surface of the setter substrate 20 in the firing process of the reference example and is more likely to fall off from the setter 1.

[0061] On the other hand, in the firing process according to this embodiment (FIG. 4(b)), the amount of powder 22 dispersed on the setter substrate 20 is greater than in the reference example. In this case, the powder 22 dispersed on the setter substrate 20 is more likely to overlap with one another. Therefore, in this embodiment, the proportion of powder 22 that is at least partially covered by other powder 22 is greater than in the reference example. In particular, the powder 22 in contact with the main surface 20a of the setter substrate 20 tends to be covered by the other powder 22. Here, it is presumed that the components of the powder 22 that are covered by the other powder 22 are less likely to volatilize. Therefore, most of the powder 22 in contact with the main surface 20a of the setter substrate 20 tends to form a fused region 26. The fired products 24, 28, etc. are fused to one another. Therefore, it is presumed that the fired product 5, which is the fired product 24 or the fired product 28, is firmly fixed to the setter 1.

[0062] Next, a modified example of the above embodiment will be described. In the following modified example, the description of the same points as the above embodiment will be omitted. Therefore, the following description will mainly focus on the points that are different from the above embodiment.

[0063] This modified example differs from the above embodiment in that it has an outermost layer that covers the main surface of the ceramic substrate and contains 90% by mass or more of alumina, and that a fired product is fixed to the outermost layer. The setter according to this modified example will be described below with reference to Fig. 5. Fig. 5 is a schematic cross-sectional view showing the setter according to the modified example.

[0064] As shown in FIG. 5, the setter 10 includes a ceramic substrate 17 and an outermost surface layer 13 that covers a main surface 17a of the ceramic substrate 17. Examples of the ceramic material that is the main material of the ceramic substrate 17 include alumina, mullite, zirconium oxide, SiC, magnesia (magnesium oxide), and yttrium oxide. When the ceramic material is mullite, the setter 10 tends to be less prone to warping and deformation even when used repeatedly. In this modification, a ceramic material in which the silica content relative to the total of alumina and silica is 1% by mass or more and 60% by mass or less is considered to be mullite.

[0065] The outermost surface layer 13 is a film-shaped portion that covers the entire main surface 17a of the ceramic substrate 17. In other words, the outermost surface layer 13 covers the entire main surface 17a. The main surface 13a of the outermost surface layer 13 corresponds to the main surface 3a of the setter 1. The ceramic substrate 17 may further include a layer corresponding to the outermost surface layer 13 on the surface opposite to the main surface 17a. The outermost surface layer 13 is formed by, for example, a known physical vapor deposition method, a chemical vapor deposition method, a printing method, or the like. The thickness of the outermost surface layer 13 may be, for example, 1 μm to 1000 μm, 50 μm to 500 μm, or 100 μm to 300 μm.

[0066] The outermost surface layer 13 contains 90% by mass or more of alumina. In other words, the content of alumina contained in the outermost surface layer 13 (alumina content of the outermost surface layer 13) is 90% by mass or more. The alumina content of the outermost surface layer 13 may be 95% by mass or more, 99% by mass or more, or even 100% by mass. The alumina content of the outermost surface layer 13 can be measured using, for example, X-ray diffraction (XRD) or ICP atomic emission spectrometry.

[0067] At least a part of the outermost layer 13 has a fired product 15 corresponding to the fired product 5 in the setter 1 fixed thereto. The thickness of the fired product 15 is the difference between the height of the outermost layer 13 and the height of the fired product 15 when measured with reference to the outermost layer 13 covering the main surface 17a of the ceramic substrate 17. The thickness of the fired product 15 can be measured by the same method as the thickness measurement of the fired product 5. In this case, the main surface 3a of the ceramic substrate 3 is read as the main surface 13a of the outermost layer 13.

[0068] Even in the setter according to the modified example described above, the same operational effects as those of the above embodiment are exhibited.

[0069] The above embodiments and modified examples illustrate one aspect of the present disclosure. Therefore, the present disclosure is not limited to the above embodiments and the above modified examples, and can be appropriately modified. For example, in the above embodiment, the fired product 5 is provided on the main surface 20a of the setter substrate 20, but it is not limited thereto. The fired product 5 may be provided not only on the main surface 20a of the setter substrate 20 but also on the back surface 20b. The characteristics (such as shape and composition including thickness and surface roughness) of the fired product 5 provided on the back surface 20b may be the same as or different from the characteristics of the fired product 5 provided on the main surface 20a. Also, in the above modified example, the fired product 15 may be provided not only on the main surface 17a of the ceramic substrate 17 but also on the back surface. In this case, the outermost layer 13 is formed on both the main surface 17a and the back surface of the ceramic substrate 17. The characteristics (such as shape and composition including thickness and surface roughness) of the outermost layer 13 formed on the back surface and the fired product 5 provided on the back surface may be the same as or different from the characteristics of the outermost layer 13 formed on the main surface 17a and the fired product 5 provided on the main surface 17a, respectively.

Example

[0070] The present disclosure will be described in more detail with reference to the following examples, but the present disclosure is not limited to these examples only.

[0071] [Production of powder] <LLTO powder A> In this example, a powder to be fixed to a setter was produced through the steps of preparing a slurry, forming a green sheet using the slurry, firing the green sheet to obtain a fired body, and pulverizing and classifying the fired body.

[0072] (Adjustment of slurry) In this process, lanthanum oxide (Kanto Chemical Co., Ltd.), anatase-type titanium oxide (Teika Corporation), and lithium carbonate (Kishida Chemical Co., Ltd.) were prepared as raw material powders. A commercially available polycarboxylic acid ester-type polymer dispersant was also prepared as a dispersant. A mixed solvent of toluene and ethyl acetate (toluene:ethyl acetate = 3:2 by mass) was prepared as a solvent. A methacrylate copolymer (Nippon Shokubai Co., Ltd., number-average molecular weight: 37,000, glass transition temperature: 19°C) was prepared as a binder. A polyester-based plasticizer (J-Plus Corporation) was also prepared as a plasticizer. Lanthanum oxide was prepared by heating it in an alumina sagger at 700°C for 1 hour.

[0073] First, a mixed powder was obtained by mixing 50.4 parts by mass of lanthanum oxide, 43.6 parts by mass of titanium oxide, and 6.0 parts by mass of lithium carbonate, which were raw powders. Next, 100 parts by mass of the mixed powder and 103.4 parts by mass of a mixed liquid of a dispersant and a solvent were placed in a nylon mill. Zirconia balls were then charged into the nylon mill, and the mixed powder and the mixed liquid were milled for 20 hours. After the milling, a binder and a plasticizer were added, and the mixture was milled for another 20 hours. Thus, a slurry was prepared. The amount of dispersant contained in the mixed liquid was 3.7 parts by mass, the amount of binder in terms of solids content was 28.4 parts by mass, and the amount of plasticizer was 19.2 parts by mass.

[0074] (Production of green sheets) In this process, first, the above slurry was contained in a jacketed round-bottom cylindrical vacuum defoaming vessel equipped with a weight-type stirrer. Subsequently, the slurry was concentrated and defoamed under the conditions of a stirrer rotation speed of 200 rpm, a vacuum atmosphere, and a jacket temperature of 40°C. The viscosity of the slurry after concentration and defoaming at 25°C was 3 Pa·s. Subsequently, the slurry was continuously coated on a base film by the doctor blade method. At this time, a coating device (doctor blade type sheet forming machine) was used. A PET film was used as the base film. Subsequently, in the coating device, the coated slurry was heated under the conditions of 100°C for 2 hours. As a result, a sheet (green sheet) with a thickness of about 800 μm and a long shape in plan view was obtained. This green sheet was peeled off from the base film.

[0075] (Firing of Green Sheet) In this process, the green sheet was fired to obtain a fired body. First, the green sheet was placed on a setter. As the setter, a setter made of alumina (manufactured by Yotai Co., Ltd., alumina content: about 99%, porosity: 16.9%, bulk specific gravity: 3.2) was used. Subsequently, the setter was placed in a heating furnace. An up-and-down type electric furnace was used as the heating furnace. Subsequently, the inside of the heating furnace was heated under the conditions of 1350°C for 1 hour. As a result, a fired body of the green sheet was obtained. After cooling the setter, this fired body was peeled off from the setter.

[0076] (Grinding and Classification of Fired Body) In this process, after grinding the fired body, the fired body was classified to obtain LLTO powder. First, the fired body was dry-grinded using a mortar. Then, by sieving the fired body, coarse particles were removed from the fired body. A sieve with a mesh size of 100 μm was used. In this way, LLTO powder A was obtained. LLTO powder A was a white powder.

[0077] <LLTO Powder B> LLTO powder B was obtained in the same manner as LLTO powder A, except that the heating conditions in the heating furnace in the firing process of the green sheet were 1200°C for 30 hours. LLTO powder B was a white powder.

[0078] <LLTO powder C> LLTO powder C was obtained by firing LLTO powder A at 1350 °C for 1 h. LLTO powder C was a brown powder.

[0079] [Evaluation of powder] (X-ray diffraction measurement) X-ray diffraction measurements (CuKα radiation) were performed on LLTO powders A and C. The obtained X-ray diffraction patterns are shown in Figs. 6(a) and (b), respectively. From the X-ray diffraction patterns, the diffraction angle and peak intensity of the maximum peak appearing in the range of the diffraction angle 2θ of each calculated peak were calculated. Also, the intensity ratio with respect to the maximum peak at a diffraction angle 2θ of 31° or more and 34° or less was calculated. Further, the content of La2Ti2O7 was calculated by performing Rietveld analysis with the maximum peak at a diffraction angle 2θ of 29.7° or more and 29.9° or less as the peak derived from La2Ti2O7. The content of La2Ti2O7 is the ratio of the mass of La2Ti2O7 to the total mass of the LLTO powder (LTO content [mass%]). The results are shown in Table 1.

[0080]

Table 1

[0081] (Particle size measurement) The mass average particle diameter D50 of LLTO powder A was calculated. First, LLTO powder A was dispersedly arranged on the sample stage. Subsequently, the sample stage was introduced into the sample chamber of the SEM, and an SEM image was taken. Subsequently, this SEM image was analyzed using image analysis software (Macview) to obtain the volume distribution of the Heywood diameter. The volume distribution of the Heywood diameter was obtained by manually surrounding 300 primary particles existing alone in the SEM image. Then, the mass average particle diameter D50 was calculated based on the volume distribution of the Heywood diameter. The mass average particle diameter D50 of LLTO powder A was 5.5 μm.

[0082] [Fabrication of setter] <Example 1> First, LLTO powder A was dispersed on the surface of the setter substrate. A 100 mm square alumina setter substrate (manufactured by Yotai Co., Ltd., alumina: approximately 99%, porosity: 16.9%, bulk specific gravity: 3.2) was used. Dispersion was performed by using a sieve to evenly distribute LLTO powder A over the entire surface of the setter substrate. The amount of LLTO powder A dispersed was 0.02 g / cm. 2 Next, the setter substrate on which the LLTO powder A was placed was fired. The firing was carried out using a high-temperature box-type electric furnace at 1350°C for 2 hours. The setter substrate was then cooled to room temperature. In this way, the LLTO powder A was baked onto the mounting surface of the setter substrate, and the setter of Example 1 was obtained.

[0083] <Example 2> A setter of Example 2 was obtained in the same manner as in Example 1, except that the amount of LLTO powder A dispersed and allocated was the amount shown in Table 2.

[0084] Example 3 A setter of Example 3 was obtained in the same manner as in Example 1, except that LLTO powder B was used instead of LLTO powder A.

[0085] <Comparative Examples 1 and 2> Setters of Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the amount of LLTO powder A dispersed and allocated was the amount shown in Table 2.

[0086] <Comparative Example 3> A setter substrate similar to that used in Example 1 was prepared, but LLTO powder A was not dispersed in the setter substrate, and the setter substrate was not fired, thereby obtaining a setter according to Comparative Example 3.

[0087] <Comparative Example 4> A setter of Comparative Example 4 was obtained in the same manner as in Example 1, except that LLTO powder C was used instead of LLTO powder A.

[0088] [Setter's Evaluation] (Thickness measurement) The thickness of the fired powder product was measured for the setters of Examples 1 and 2 and Comparative Examples 1 and 2. First, a laser displacement meter (Keyence Corporation, product name: LT-9010M) was used to measure the height displacement between two points. The measurement conditions were a scan distance of 50,000 μm, a scan speed of 1,000 μm / sec, and a scan pitch of 1 μm. The two points were selected arbitrarily from the area where the powder was applied (coated area) and the area where the powder was not applied (uncoated area). Next, the measurement data was baseline-corrected based on the measurement data from the uncoated area. The reference height was calculated from the average value of 5,000 arbitrary points in the uncoated area, and the coated area height was calculated from the average value of 20,000 arbitrary points in the coated area. The coating thickness was then calculated from the difference between the two. The results are shown in Table 2.

[0089] (surface roughness measurement) The surface roughness of the setters of Examples 1 and 2 and Comparative Examples 1 to 3 was measured. First, using a surface roughness meter (manufactured by Mitutoyo Corporation, product name: SURFTEST SJ-201), the surface roughness was measured at five arbitrary points selected from the coating area, and the average value and standard deviation were calculated. The measurement conditions were a measurement range of 5 mm and a scan speed of 0.4 mm / sec. The results are shown in Table 2.

[0090] [Table 2]

[0091] (Adhesion evaluation) The setters of Examples 1 to 3 and Comparative Examples 1, 2, and 4 were evaluated for the presence or absence of the fired product falling off when the surface of the fired product was wiped by hand. In Examples 1 and 3, little of the fired product fell off when the surface was wiped, and the fired product was fixed over the entire coating area. On the other hand, in Comparative Example 4, the fired product fell off over the entire coating area when the surface was wiped. The surface appearances of the setters of Example 1 and Comparative Example 4 before and after evaluation are shown in Figures 7(a) and (b), respectively. The surface appearances of the setters of Example 2 and Comparative Examples 1 and 2 before and after evaluation are shown in Figures 8(a) to (c), respectively. In each of Figures 7(a), (b) and 8(a) to (c), the images shown before the arrows show the appearance before evaluation, and the images shown after the arrows show the appearance after evaluation.

[0092] (Firing test with setter substrate) A mixture of powder obtained from the setter substrate (setter powder) and LLTO powder A or LLTO powder C was fired, and the fired mixture was evaluated. First, a setter substrate similar to the setter substrate used in Example 1 was prepared. The main surface of the setter substrate was then pulverized to obtain setter powder. Next, LLTO powder A or C was mixed with the setter powder in a mass ratio of approximately 1:1 to obtain a mixture. This mixture was then fired at 1350°C for 5 hours. A high-temperature box-type electric furnace was used for firing. X-ray diffraction measurements (CuKα radiation) were then performed on the fired mixture. The obtained X-ray diffraction patterns are shown in Figures 9 and 10, respectively. Figure 9 shows the X-ray diffraction pattern of a fired product of the mixture of LLTO powder A and setter powder. Figure 10 shows the X-ray diffraction pattern of a fired product of the mixture of LLTO powder C and setter powder.

[0093] In the X-ray diffraction pattern shown in FIG. 9, peaks identified to alumina, lanthanum lithium titanate, a composite oxide of lanthanum and aluminum, and a composite oxide of lanthanum, titanium, and aluminum were confirmed. Therefore, when alumina and LLTO powder A, which are in contact with each other, are calcined, it is believed that a composite oxide of lanthanum and aluminum and a composite oxide of lanthanum, titanium, and aluminum are produced. Furthermore, in the X-ray diffraction pattern shown in FIG. 10, peaks identified to alumina and lanthanum lithium titanate were confirmed. On the other hand, peaks identified to a composite oxide of lanthanum and aluminum and a composite oxide of lanthanum, titanium, and aluminum were not confirmed. Therefore, when alumina and LLTO powder C, which are in contact with each other, are calcined, it is believed that a composite oxide of lanthanum and aluminum and a composite oxide of lanthanum, titanium, and aluminum are not produced, or are hardly produced at all.

[0094] (Analysis of interface components between setter substrate and fired product) The components located at the interface between the setter substrate and the fired product in the setter of Example 1 were evaluated. First, the setter of Example 1 was roughly crushed, and a portion including the main surface was separated to obtain a crushed material. The crushed material was then further crushed in a mortar to obtain a measurement sample. X-ray diffraction measurement was then performed on this measurement sample. The obtained X-ray diffraction pattern is shown in FIG. 11. In the X-ray diffraction pattern shown in FIG. 11, peaks identified as alumina, lanthanum lithium titanate, a composite oxide of lanthanum and aluminum, and a composite oxide of lanthanum, titanium, and aluminum were confirmed. This confirmed the presence of a composite oxide of lanthanum and aluminum, and a composite oxide of lanthanum, titanium, and aluminum in the setter of Example 1. Furthermore, comparing FIGS. 9 to 11, the X-ray diffraction pattern shown in FIG. 11 is more similar to the X-ray diffraction pattern of FIG. 9 than the X-ray diffraction pattern of FIG. 10.

[0095] [Fabrication of lithium ion conductive sheet] The green sheet formed by the above method was placed on the mounting surface of the setter of Example 1. The setter was then placed in an electric furnace. The electric furnace was then heated from room temperature to 500°C over 54 hours, and the green sheet placed on the setter was degreased. The setter was then placed in a high-temperature box-type electric furnace. The temperature inside the high-temperature box-type electric furnace was then raised to 1350°C, and the temperature was maintained for 1 hour to sinter the green sheet placed on the setter. The setter was then cooled to room temperature, and the sintered green sheet was then peeled off from the setter. In this way, a composite oxide sheet (lithium ion conductive sheet) having a perovskite-type crystal structure composed of oxides containing Li, La, and Ti as constituent elements was obtained.

[0096] (Reusability assessment) The change in the surface condition of the setter when it was repeatedly used to sinter a lithium ion conductive sheet was evaluated. First, the setter of Example 1 was used repeatedly 10 times to prepare the above-mentioned lithium ion conductive sheet. Then, the surface condition of the coated area of ​​the setter was observed using a microscope. A similar evaluation was also performed using the setter of Comparative Example 3. With the setter of Example 1, no peeling of the sintered product occurred even after the test, and no surface deterioration was observed. With the setter of Comparative Example 3, roughness occurred on the surface of the setter, and part of the surface peeled off. Furthermore, X-ray diffraction measurement was performed on the roughened area of ​​the setter of Comparative Example 3. In the obtained X-ray diffraction pattern, a peak identified as LiAl5O8 was confirmed. [Explanation of symbols]

[0097] 1, 10...setter, 3, 17...ceramic substrate, 5, 15, 24, 28...fired product, 13...outermost layer, 3a, 13a, 20a...main surface, 17a...main surface, 20...setter substrate, 20b...rear surface, 22...powder, 26...fused region, 30...lithium ion conductive sheet.

Claims

1. a step of firing the powder dispersed on the main surface of the setter substrate to bake the powder onto the main surface; the powder contains lanthanum lithium titanate; the alumina content in the main surface is 90% by mass or more, The amount of the powder dispersed on the main surface is 0.004 g / cm ２ 0.1g / cm or more ２ Below is the A method for manufacturing a setter.

2. The method for manufacturing a setter according to claim 1 , wherein the powder has a mass average particle diameter D50 of 200 μm or less.

3. In the X-ray diffraction pattern of the powder, the maximum peak intensity at a diffraction angle 2θ of 31° or more and 34° or less is defined as intensity I Ａ The maximum peak intensity at a diffraction angle 2θ of 10° or more and 13° or less is defined as intensity I Ｂ When this is done, the intensity I Ｂ / Intensity I Ａ The method for producing a setter according to claim 1 or 2, wherein is 0.05 or more.

4. In the X-ray diffraction pattern of the powder, the maximum peak intensity at a diffraction angle 2θ of 31° or more and 34° or less is defined as intensity I Ａ The maximum peak intensity at a diffraction angle 2θ of 29° or more and 31° or less is defined as intensity I Ｃ When this is done, the intensity I Ｃ / Intensity I Ａ The method for manufacturing a setter according to claim 1 or 2, wherein is 0.035 or less.

5. La in the powder ２ Ti ２ O ７ The method for producing a setter according to claim 1 or 2, wherein the content of is less than 5 mass %.

6. a ceramic substrate having a main surface containing 90 mass % or more of alumina; a fired product of lanthanum lithium titanate fixed to a main surface of the ceramic substrate; A setter comprising: The thickness of the fired product is 10 μm or more and 300 μm or less.

7. The setter according to claim 6, wherein the surface roughness of the fired product is 6 μm or more.

8. 7. The setter according to claim 6, wherein the standard deviation of the surface roughness of the fired product is 2 μm or less.

9. 7. The setter according to claim 6, wherein at least one of a composite oxide of lanthanum and aluminum and a composite oxide of lanthanum, titanium and aluminum is located at the interface between the main surface and the fired product.

10. a ceramic substrate; an outermost layer covering a main surface of the ceramic substrate and containing 90 mass % or more of alumina; Equipped with a fired product of lanthanum lithium titanate is fixed to at least a portion of the outermost surface layer; The thickness of the fired product is 10 μm or more and 300 μm or less.

11. The setter according to any one of claims 6 to 10, wherein the setter is a setter for firing a lithium ion conductive sheet.

12. A method for producing a lithium ion conductive sheet, comprising placing a green sheet on the setter according to any one of claims 6 to 10 and firing it.

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