Multilayer ceramic component, electrode paste, and co-material particles

Abstract

A multilayer ceramic component that is obtained by firing and has a structure in which internal electrode layers and dielectric layers are alternatingly laminated, the average value of the area ratios of the areas of existing co-material particles to the total area of the internal electrode layers being 0.0001-0.15 in a cut surface obtained by cutting the internal electrode layers orthogonally with respect to the lamination interface.

Description

Multilayer ceramic components, electrode pastes, and co-material particles

[0001] This disclosure relates to multilayer ceramic components, electrode pastes, and co-material particles.

[0002] Multilayer ceramic components such as multilayer ceramic capacitors (MLCCs) are made of barium titanate (BaTiO2). ３ A dielectric layer mainly composed of particles, and Ni particles / BaTiO ３ The device consists of a laminated structure with an internal electrode layer primarily composed of particles (hereinafter referred to as "common material BTO"), and the market demands higher capacity and smaller size (thinner dielectric and electrode layers). Thinning requires miniaturization of each particle. The role of the common material is to raise the shrinkage initiation temperature of the internal electrode layer in order to mitigate cracks (breakdown of connections in the internal electrode layer), distortion of layer interfaces, and fractures that occur due to the large difference in thermal shrinkage history (shrinkage initiation temperature) between the dielectric layer and the internal electrode layer during firing.

[0003] Patent Document 1 describes a laminated ceramic component having a structure in which internal electrode layers and dielectric layers are alternately stacked, wherein the internal electrode layers contain 0.01 to 12% by weight of co-material relative to the weight of metal powder, the average particle size of the co-material is within 30% of the average particle size of the metal powder, and after sintering, the content ratio of the co-material present in the internal electrode layers to the total co-material content is 0.006 to 0.1.

[0004] Furthermore, Patent Document 2 describes a particle with an average primary particle diameter of 20 nm or more and 80 nm or less, and a 50% diameter of the cumulative frequency distribution of aggregated particles in an aqueous solvent. ５０ and 95% diameter D ９５ D represented by ９５ / D ５０ The document describes barium titanate particle powder in which the value of is 1.2 or greater and 5.0 or less, the probability of presence of fused primary particles is 1% or greater and 15% or less, and the ignition loss is 3.0% by weight or less.

[0005] Patent Document 1: Japanese Unexamined Patent Publication No. 2013-251538 Patent Document 2: Japanese Unexamined Patent Publication No. 2025-62804

[0006] One embodiment of this disclosure aims to solve the problem of providing a multilayer ceramic component with excellent continuity of the internal electrode layer. Another embodiment of this disclosure aims to solve the problem of providing an electrode paste and co-material particles that can form an internal electrode layer with excellent continuity.

[0007] The means for solving the above problems include the following embodiments: <1> A laminated ceramic component having a structure in which an internal electrode layer and a dielectric layer are alternately stacked after firing, wherein the average area ratio of the area of ​​the co-material particles present to the total area of ​​the internal electrode layer in a cut surface obtained by cutting the internal electrode layer perpendicular to the stacking interface is 0.0001 to 0.15. <2> The laminated ceramic component according to <1>, wherein in the internal electrode layer contained in the center of the laminated ceramic component, the internal electrode layer is divided into three equal parts in the thickness direction, and 50% or more of the co-material particles are present in the central part. <3> The laminated ceramic component according to <1> or <2>, wherein the internal electrode layer contained in the center of the laminated ceramic component is divided into three equal parts in the thickness direction, and in the central part, with an arbitrary point around the center of the laminated ceramic component as the center point, a length 25 times the thickness of the internal electrode layer is taken from there in the width direction, and when this is divided into five equal parts in the width direction, the variation in the area ratio of the co-material particles present in each of the five divided parts is within ±100% of the average value. <4> The laminated ceramic component according to any one of <1> to <3>, wherein the thickness of the internal electrode layer is 500 nm or less. <5> An electrode paste for constituting an internal electrode layer, comprising electrode particles and co-material particles, wherein the electrode particles are Ni particles or Cu particles, the co-material particles are barium titanate particles, and the mass ratio of the co-material particles to the total mass of the electrode particles is 1% by mass to 20% by mass. <6> The electrode paste according to <5>, wherein the average physical diameter obtained by electron microscopy observation of the above-mentioned co-material particles is in the range of 1% to 25% of the average physical diameter obtained by electron microscopy observation of the above-mentioned electrode particles. <7> The electrode paste according to <5> or <6>, wherein the crystallite diameter of the above-mentioned co-material particles is 1 nm to 20 nm, the BET diameter is 1 nm to 40 nm, and the average physical diameter obtained by electron microscopy observation is 1 nm to 40 nm. <8> The electrode paste according to any one of <5> to <7>, wherein the coefficient of variation of the physical diameter of the above-mentioned co-material particles is 0.5 or less. <9> The electrode paste according to any one of <5> to <8>, wherein the crystallite diameter / BET diameter value of the above-mentioned co-material particles is 0.5 to 1.5.<10> An electrode paste according to any one of <5> to <9>, wherein the crystallite size / physical average diameter value obtained by electron microscopy observation of the above-mentioned co-material particles is 0.5 to 1.5. <11> Co-material particles that are barium titanate particles, wherein the crystallite size / physical average diameter value obtained by electron microscopy observation is 0.5 to 1.5.

[0008] According to one embodiment of the present disclosure, a multilayer ceramic component having excellent continuity of the internal electrode layer is provided. According to another embodiment of the present disclosure, an electrode paste and co-material particles capable of forming an internal electrode layer with excellent continuity are provided.

[0009] The contents of this disclosure will be described in detail below. In this specification, the term "process" includes not only independent processes but also processes that are not clearly distinguishable from other processes, as long as the intended function of the process is achieved. In this disclosure, "mass%" and "weight%" are synonymous, and "parts by mass" and "parts by weight" are synonymous. Furthermore, in this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

[0010] (Laminated ceramic component) The laminated ceramic component according to this disclosure has a structure in which an internal electrode layer and a dielectric layer are alternately stacked, formed by firing, and in the cut surface obtained by cutting the internal electrode layer perpendicular to the lamination interface, the average area ratio of the area of ​​the existing co-material particles to the total area of ​​the internal electrode layer is 0.0001 to 0.15.

[0011] Typically, metal powders such as Ni and Cu used in internal electrode paste have lower melting points than ceramic powders used in dielectric layers, resulting in a lower temperature at which sintering shrinkage begins. Therefore, ceramic powders are added as co-materials to raise the temperature so that the shrinkage initiation temperature is as close as possible to that of the dielectric. The ceramic powder used as a co-material during the firing process of the internal electrode layer is absorbed by the dielectric layer and ultimately affects the dielectric properties, so it is designed to have the same or a similar composition as the dielectric layer. Typically, barium titanate (BaTiO), which is similar in composition to that of the dielectric layer, is used. ３) is used as the main component of the co-material, and various oxide-based minor components may be used to further increase the sintering start temperature. Furthermore, since the above co-material must be distributed between the electrode particles to limit sintering, particles smaller than the electrode particles are used, and the amount added is adjusted according to the firing temperature of the multilayer ceramic component. In this case, if co-material particles having a particle size less than or equal to a certain extent relative to the electrode particles are used, depending on the content, there will be co-material particles in the center of the internal electrode layer that are not squeezed out into the dielectric layer during firing. These trapped co-materials control the sintering shrinkage of the internal electrode within a range that does not interfere with the electrical properties of the electrode, and also affect the improvement of electrode connectivity, thereby increasing the capacity of the multilayer ceramic component. According to the multilayer ceramic component of this disclosure, by having an average area ratio of the area of ​​existing co-material particles to the total area of ​​the internal electrode layer of 0.0001 to 0.15, the content, particle size, and variation of the co-material particles added to the internal electrode layer can be adjusted, and the high sintering shrinkage control power of the above co-material particles can be used to provide a multilayer ceramic component with excellent continuity of the internal electrode layer. In this disclosure, "continuity of the internal electrode layer" means that the internal electrode layer is not broken by cracks or other fractures and is in communication with the other layer.

[0012] <Average value of the area ratio of the area of ​​existing co-material particles to the total area of ​​the internal electrode layer> In the multilayer ceramic component according to this disclosure, the average value of the area ratio of the area of ​​existing co-material particles to the total area of ​​the internal electrode layer in the cut surface obtained by cutting the internal electrode layer perpendicular to the lamination interface is 0.0001 to 0.15. If the average value of the area ratio of existing co-material particles is less than 0.0001, the effect of suppressing electrode breakage cannot be sufficiently obtained. On the other hand, if it exceeds 0.15, the capacity of the multilayer ceramic component will decrease. Furthermore, in the multilayer ceramic component according to this disclosure, from the viewpoint of the continuity of the internal electrode layer, it is preferable that the ratio is 0.001 to 0.15, more preferably 0.005 to 0.15, and particularly preferable 0.008 to 0.15.

[0013] The average area ratio of the area of ​​the co-material particles to the total area of ​​the internal electrode layer can be adjusted by adjusting the content, particle size, and dispersion state of the co-material particles.

[0014] The method for measuring the average area ratio of the area of ​​existing co-material particles to the total area of ​​the internal electrode layer is as follows: The area of ​​the co-material particles is measured from images taken with an electron microscope at the cut surface obtained by cutting the internal electrode layer perpendicular to the lamination interface, and the value of area of ​​co-material particles / total area of ​​the internal electrode layer is calculated by dividing this by the total area of ​​the internal electrode layer, and the average is taken over five or more cut surfaces to calculate the value.

[0015] <Proportion of Co-material Particles in the Central Part> In the multilayer ceramic component according to this disclosure, from the viewpoint of the continuity of the internal electrode layer, the internal electrode layer contained in the central part of the multilayer ceramic component is preferably divided into three equal parts in the thickness direction, and it is preferable that 50% or more of the Co-material Particles are present in the central part, more preferably 60% or more, and even more preferably 70% or more.

[0016] The proportion of co-material particles in the central part can be adjusted by controlling the content, particle size, particle size distribution, and dispersion state of the co-material particles.

[0017] The method for measuring the proportion of co-material particles in the central part is as follows: In the internal electrode layer contained in the central part of the multilayer ceramic component, the area of ​​co-material particles in the central part is measured using an electron microscope at the cut surface obtained by cutting the internal electrode layer perpendicular to the lamination interface, and the value of area of ​​co-material particles in the central part / area of ​​all co-material particles in the internal electrode layer is calculated by dividing this by the area of ​​all co-material particles present in the internal electrode layer, and the average is taken over five or more cut surfaces to calculate the central part. The central part of the multilayer ceramic component is the central part when the multilayer ceramic component is divided into three equal parts along the lamination direction, the central part when the multilayer ceramic component is divided into three equal parts in a first direction parallel to the plane perpendicular to the lamination direction, and the central part when the multilayer ceramic component is divided into three equal parts in a second direction parallel to the plane perpendicular to the lamination direction and perpendicular to the first direction.

[0018] <Average value of variation in the area ratio of existing common material particles> In the multilayer ceramic component according to this disclosure, from the viewpoint of the continuity of the internal electrode layer, the internal electrode layer is divided into three equal parts in the thickness direction at the center of the multilayer ceramic component in the stacking direction, and in the central part of the multilayer ceramic component, an arbitrary point around the center of the multilayer ceramic component is taken as the center point, and a length of 25 times the thickness of the internal electrode layer is taken in the width direction from there, and this is divided into five equal parts in the width direction, it is preferable that the variation in the area ratio of common material particles present in each of the five divided parts is within ±100% of the average value, more preferably within ±80%, and even more preferably within ±50%. If the variation in the area ratio is within ±100% of the average value, the variation in the amount of common material remaining in each slot in the width direction is small, and it is possible to suppress the occurrence of electrode breakage triggered by parts with a small amount of remaining common material.

[0019] The average value of the variation in the area ratio of existing co-material particles can be adjusted by adjusting the particle size, particle size distribution, and dispersion state of the co-material particles.

[0020] The method for measuring the average value of the variation in the area ratio of co-material particles present is as follows: At the center of the laminated ceramic component in the lamination direction, the internal electrode layer is cut perpendicular to the lamination interface, and at the cut surface, an electron microscope is used to measure the area ratio of co-material particles present in each of the five equal parts. The average value and standard deviation of the area ratio of co-material particles present in each of the five parts are calculated, the standard deviation divided by the average value is calculated as the variation, and the average of the variations across five or more surfaces is taken.

[0021] <Internal Electrode Layer> The multilayer ceramic component according to this disclosure has a structure in which an internal electrode layer and a dielectric layer are alternately stacked, formed by firing. The internal electrode layer is preferably mainly composed of base metals such as Ni (nickel), Cu (copper), and Sn (tin). Alternatively, the internal electrode layer may be mainly composed of noble metals such as Pt (platinum), Pd (palladium), Ag (silver), and Au (gold), or alloys containing these. In this disclosure, the main component refers to a component that accounts for 50% by mass or more, and is preferably 80% by mass or more.

[0022] The internal electrode layer preferably contains a metal and co-material particles, and more preferably contains Ni or Cu and co-material particles. Furthermore, the internal electrode layer is preferably a layer composed of a metal and co-material particles. Moreover, the internal electrode layer is preferably a layer formed by firing metal particles and co-material particles. There are no particular restrictions on the number of internal electrode layers in the multilayer ceramic component according to this disclosure, and they may be appropriately selected as desired.

[0023] The thickness of the internal electrode layer is not particularly limited, but is preferably 500 nm or less, more preferably 50 nm to 500 nm, and even more preferably 100 nm to 500 nm. When the thickness of the internal electrode layer is 500 nm or less, the number of laminated layers can be increased even for the same size of the multilayer ceramic component, which provides excellent capacitance and further exerts the effect of excellent continuity of the internal electrode layer in the present disclosure. The thickness of the internal electrode layer is an arithmetic average value obtained by performing measurements at 5 or more points with an electron microscope on a fractured cross-section formed by fracturing the internal electrode layer perpendicularly to the lamination interface.

[0024] <Dielectric Layer> The multilayer ceramic component according to the present disclosure has a structure in which internal electrode layers and dielectric layers are alternately laminated and fired. The dielectric layer is mainly composed of, for example, a ceramic material having a perovskite structure represented by the formula ABO ３ . The perovskite structure includes ABO that deviates from the stoichiometric composition ３ -α. For example, as the ceramic material, BaTiO ３ (barium titanate), CaZrO ３ (calcium zirconate), CaTiO ３ (calcium titanate), SrTiO ３ (strontium titanate), Ba that forms a perovskite structure １－ｘ－ｙ Ca ｘ Sr ｙ Ti １－ｚ Zr ｚ O ３ (0≦x≦1, 0≦y≦1, 0≦z≦1) and the like can be used. Among them, BaTiO from the viewpoint of dielectric constant ３ (barium titanate) is preferably mentioned. This BaTiO ３ can generally be obtained by reacting a titanium raw material such as titanium dioxide with a barium raw material such as barium carbonate to synthesize barium titanate. As methods for synthesizing the ceramic constituting the dielectric layer, various conventional methods are known, such as a solid phase method, a sol-gel method, a hydrothermal method and the like. In the present disclosure, any of these can be adopted.

[0025] Depending on the purpose, a predetermined additive compound may be added to the material forming the dielectric layer. Examples of additive compounds include oxides of Mn (manganese), V (vanadium), Cr (chromium), rare earth elements (Y (yttrium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holomium), Er (erbium), Tm (thulium), and Yb (ytterbium)), as well as oxides or glasses of Co (cobalt), Ni (nickel), Zn (zinc), Li (lithium), B (boron), Na (sodium), K (potassium), and Si (silicon).

[0026] The number of dielectric layers in the multilayer ceramic component relating to this disclosure is not particularly limited and may be selected as desired. Furthermore, the thickness of the dielectric layers is not particularly limited and may be selected as desired.

[0027] The multilayer ceramic component according to this disclosure may further have known configurations, such as an external electrode and a cover layer that covers a structure in which internal electrode layers and dielectric layers are alternately stacked. Furthermore, a multilayer ceramic capacitor is a preferred example of the multilayer ceramic component according to this disclosure.

[0028] The dimensions of the multilayer ceramic components relating to this disclosure are, for example, 0.2 mm in length, 0.125 mm in width, and 0.125 mm in height, or 0.4 mm in length, 0.2 mm in width, and 0.2 mm in height, or 0.6 mm in length, 0.3 mm in width, and 0.3 mm in height, or 1.0 mm in length, 0.5 mm in width, and 0.5 mm in height, or 3.2 mm in length, 1.6 mm in width, and 1.6 mm in height, or 4.5 mm in length, 3.2 mm in width, and 2.5 mm in height, but are not limited to these dimensions.

[0029] (Electrode Paste) The electrode paste according to the present disclosure is an electrode paste for forming an internal electrode layer, which comprises electrode particles and co-material particles, wherein the electrode particles are Ni particles or Cu particles, the co-material particles are barium titanate particles, and the mass ratio of the co-material particles to the total mass of the electrode particles is 1 mass% to 20 mass%. It is preferable that the internal electrode layer in the multilayer ceramic component according to the present disclosure is formed from the electrode paste according to the present disclosure.

[0030] <Electrode Particles> The electrode paste according to the present disclosure comprises electrode particles, and the electrode particles are Ni particles or Cu particles. Among them, Ni particles are preferred. From the viewpoint of the continuity of the internal electrode layer, the physical average diameter of the electrode particles obtained by electron microscope observation is preferably 10 nm to 300 nm, more preferably 20 nm to 200 nm, and even more preferably 40 nm to 150 nm. The physical average diameter of the particles in the present disclosure obtained by electron microscope observation is indicated by an average value obtained by respectively measuring the particle diameters of 350 primary particles shown in a scanning or transmission electron micrograph.

[0031] From the viewpoint of the continuity of the internal electrode layer, the physical average diameter of the co-material particles obtained by electron microscope observation is preferably in the range of 1% to 25%, more preferably in the range of 5% to 25%, and even more preferably in the range of 10% to 25%, relative to the physical average diameter of the electrode particles obtained by electron microscope observation.

[0032] <Co-Material Particles> The electrode paste according to the present disclosure comprises co-material particles, the co-material particles are barium titanate particles, and the mass ratio of the co-material particles to the total mass of the electrode particles is 1 mass% to 20 mass%. From the viewpoint of the continuity of the internal electrode layer, the mass ratio of the co-material particles to the total mass of the electrode particles is preferably 2 mass% to 20 mass%, more preferably 3 mass% to 18 mass%, and even more preferably 5 mass% to 15 mass%.

[0033] The crystallite size of the above-mentioned co-material particles is preferably 0.5 nm to 50 nm, more preferably 1 nm to 30 nm, and particularly preferably 1 nm to 20 nm, from the viewpoint of the continuity of the internal electrode layer. The crystallite size of particles in the present disclosure is measured by X-ray diffraction. More specifically, powder X-ray diffraction measurement is performed using a powder X-ray diffractometer, and for barium titanate particles, the crystallite size is calculated from the peak of the (111) plane.

[0034] The BET diameter of the above-mentioned co-material particles is preferably 0.5 nm to 80 nm, more preferably 1 nm to 40 nm, and particularly preferably 5 nm to 30 nm, from the viewpoint of the continuity of the internal electrode layer. The BET diameter of particles in the present disclosure corresponds to the diameter of a sphere having the same surface area as the specific surface area determined by the BET method (i.e., the BET specific surface area). The BET diameter D can be determined by the following conversion formula. D = [6 / (Sg × ρ)] × 1000 where D is the BET diameter (nm), and Sg is the BET specific surface area of the particle (m ２ / g), and ρ is the density of the particle (g / cm ３ ). The density value of barium titanate is set to 6.0.

[0035] The physical average diameter of the above-mentioned co-material particles obtained by electron microscope observation is preferably 0.5 nm to 80 nm, more preferably 1 nm to 40 nm, and particularly preferably 5 nm to 30 nm, from the viewpoint of the continuity of the internal electrode layer.

[0036] Further, from the viewpoint of the continuity of the internal electrode layer, it is preferable that the crystallite size of the above-mentioned co-material particles is 1 nm to 20 nm, the BET diameter is 1 nm to 40 nm, and the physical average diameter obtained by electron microscope observation is 1 nm to 40 nm.

[0037] It is preferable that the coefficient of variation of the physical diameter of the above-mentioned co-material particles is 0.5 or less. When the coefficient of variation of the physical diameter is 0.5 or less, the amount of relatively small and large co-material particles is small, and as a result, the amount of co-material remaining after firing falls within the desired range, the variation in arrangement is small, and the effect of suppressing internal electrode breakage is sufficiently obtained. The coefficient of variation of the physical diameter V can be determined by measuring the particle diameter of 350 particles from electron microscope images, taking the average value as the physical average diameter obtained by electron microscope observation, and dividing the standard deviation of the particle distribution by the physical average diameter obtained by electron microscope observation. Coefficient of variation of physical diameter V = Standard deviation of particle distribution / Physical average diameter obtained by electron microscope observation

[0038] The crystallite diameter / BET diameter value for the above-mentioned co-material particles is preferably 0.3 to 2.0, more preferably 0.5 to 1.5, and even more preferably 0.6 to 1.4. The "crystallite diameter / BET diameter" represents the ratio of the crystallite size of the co-material particles to the primary particle size (the smallest unit in the case of aggregated particles). If it is within the above range, the crystallinity is sufficiently high, and the crystallite diameter and primary particle size are close, resulting in uniform particle size and high dispersion of the co-material particles when formed into an electrode paste.

[0039] The crystallite size / physical average diameter obtained by electron microscopy observation of the above-mentioned co-material particles is preferably 0.5 to 1.5, more preferably 0.5 to 1.2, even more preferably 0.5 to 1.0, and particularly preferably 0.7 to 1.0. The "crystallite size / physical average diameter obtained by electron microscopy observation" represents the ratio of the crystallite size to the physical primary diameter of the co-material particles. If it is within the above range, the crystallinity is sufficiently high, and the crystallite size and the physical average diameter obtained by electron microscopy are close, resulting in a uniform particle size and high dispersion state of the co-material particles when formed into an electrode paste.

[0040] The particle size distribution of the electrode particles and the co-material particles is preferably narrow. In addition to counting the particle size distribution by image analysis of particle images taken with an electron microscope, it is also possible to calculate the particle size distribution by measuring small-angle X-ray scattering of the particle dispersion and performing particle size analysis. Furthermore, the particle size distribution can also be relatively compared and measured by performing dynamic light scattering measurements on the particle dispersion and calculating the PDI (poly dispersion index). In addition to the coefficient of variation index, D10, D50, and D90 (particle sizes at which the cumulative frequencies are 10%, 50%, and 90%, respectively) can be extracted from particle size data calculated from electron microscope images or cumulative distributions measured by dynamic light scattering, and the smaller the value of (D90 - D10) / D50, the smaller the particle size distribution, which can be used as an index, and there is a preferred range.

[0041] Regarding the physical properties of the above-mentioned co-material particles, from the viewpoint of ease of dispersion into Ni particles in the dispersion of the internal electrode paste, the angle of repose, bulk density, acid-base properties of the particle surface (acid and base spot density), specific surface area, pore distribution, and hydrophilicity contribute, and it is preferable that each of these properties be within an appropriate range. These can be evaluated by measurements such as angle of repose measurement, bulk density measurement, temperature-induced desorption method, and gas adsorption measurement. In addition, other measurement methods that can obtain physical property indicators of the particle surface can also be used, such as X-ray photoelectron spectroscopy (electron structure and chemical state) and infrared spectroscopy (adsorbed species and bonding state of particles), and it is preferable that each of these properties be within an appropriate range for the dispersion of the co-material particles.

[0042] <Organic Solvent> The electrode paste according to this disclosure may further contain an organic solvent. The organic solvent used in the electrode paste according to this disclosure is a component that dissolves resin components and stably disperses inorganic components such as electrode particles and co-material particles in the paste. When applied (printed) to a green sheet or circuit board of an electronic component, it has the function of uniformly spreading these powders and dissipating into the atmosphere by the time of firing.

[0043] Examples of such organic solvents include terpineol (α, β, γ and mixtures thereof), dihydroterpineol, octanol, decanol, tridecanol, dibutyl phthalate, butyl acetate, butyl carbitol, butyl carbitol acetate, and dipropylene glycol monomethyl ether.

[0044] <Binder> The electrode paste according to this disclosure may further contain a binder. Preferably, one or more organic resins such as ethylcellulose, nitrocellulose, acrylic, and polyvinyl butyral are selected and used as the binder. The molecular weight is assumed to be soluble in the organic solvent used, but preferably a resin with a weight-average molecular weight of 20,000 to 200,000 is used. There are no particular restrictions on the binder content in the electrode paste, but 1.0% to 5.0% by mass is preferred, and 2.0% to 4.0% by mass is more preferred.

[0045] Aromatic hydrocarbons or aliphatic hydrocarbons may be added to the electrode paste as diluents to further adjust its viscosity. For example, aliphatic hydrocarbons such as decane, nonane, and heptane, aliphatic higher alcohols with a melting point of 190°C to 350°C and preferably having 8 to 20 carbon atoms, such as decanol and octanol, or aromatic hydrocarbons such as benzene and toluene can be used alone or in combination. These serve to adjust the drying rate after printing the electrode paste and to impart appropriate viscosity characteristics to the electrode paste.

[0046] Furthermore, known additives for electrode pastes, such as defoamers, dispersants, plasticizers, surfactants, and thickeners, may be added to the electrode paste as needed.

[0047] For the manufacture of the electrode paste, known methods such as a three-roll mill or a ball mill can be used, and the electrode paste can be printed (applied) using known printing or coating methods.

[0048] (Co-material particles) The co-material particles according to this disclosure are barium titanate particles, and the crystallite size / physical average diameter value obtained by electron microscopy observation is 0.5 to 1.5. The co-material particles according to this disclosure can be suitably used in the electrode paste according to this disclosure.

[0049] The preferred embodiment of the co-material particles according to this disclosure is the same as the preferred embodiment of the co-material particles in the electrode paste according to this disclosure, except as described later. The crystallite size / physical average diameter obtained by electron microscopy observation of the co-material particles according to this disclosure is preferably 0.5 to 1.2, more preferably 0.5 to 1.0, and particularly preferably 0.7 to 1.0. Within the above range, the crystallinity is sufficiently high, and the crystallite size and the physical average diameter obtained by electron microscopy are close, so the particle size of the co-material particles when formed into an electrode paste is uniform and the dispersion state is high.

[0050] The following shows one embodiment of the multilayer ceramic component, electrode paste, and co-material particles relating to this disclosure, but it goes without saying that this disclosure is not limited thereto.

[0051] (Example 1) <Preparation of barium titanate particles> 10 g of barium hydroxide octahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was mixed with 24 mL of ultrapure water and dissolved in a pressure-resistant container under a nitrogen atmosphere at a liquid temperature of 90°C for 2 hours while stirring to prepare a barium solution for precursor solution preparation. To the above barium solution for precursor solution preparation, 5.69 mL of titanium tetrachloride aqueous solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., titanium equivalent concentration: 16% to 17% by mass) was added while stirring to prepare the precursor titanium hydroxide (specifically, TiO(OH) metatitaniumate) ２A colloidal solution was prepared. 28 g of barium hydroxide octahydrate was added to 28 mL of ultrapure water and dissolved in a pressure vessel under a nitrogen atmosphere at a liquid temperature of 100°C for 2 hours while stirring to prepare a barium raw material solution. The precursor titanium hydroxide colloid solution was added to the above barium raw material solution while stirring and held in a pressure vessel under a nitrogen atmosphere at a liquid temperature of 70°C for 2 hours, after which it was cooled to room temperature. A washing solution was added to the obtained reaction solution, and the supernatant was removed by centrifugation multiple times. After that, the mixture was dried in an atmosphere at a temperature of 150°C to obtain barium titanate particles. Cold water, warm water, and aqueous acetic acid were used sequentially as washing solutions. The crystallite size of the obtained barium titanate particles was 18 nm, the BET size was 35 nm, and the physical mean size obtained by electron microscopy was 20 nm. The coefficient of variation of the physical size obtained by electron microscopy was 0.29.

[0052] <Preparation of Electrode Paste> Next, an electrode paste with the following composition was prepared. The component composition of the electrode paste was 45% by mass of nickel particles (physical mean diameter obtained by electron microscopy observation of 100 nm), 9.0% by mass of the obtained barium titanate particles, 2.8% by mass of vehicle, and 43.2% by mass of organic solvent (terpineol). The vehicle consisted of 13% by mass of ethylcellulose (molecular weight 70,000) as a resin component and 87% by mass of terpineol as an organic solvent, and was prepared by heating to 60°C.

[0053] <Fabrication of Multilayer Ceramic Capacitors> An electrode paste obtained was printed onto a dielectric sheet of barium titanate particles with a thickness of 0.5 μm, dried, stacked in 20 layers, pressed together, and cut to produce a chip measuring 3.2 mm x 1.6 mm. After debinding, this chip was fired at 1,260°C in a weakly reducing atmosphere. After firing, a multilayer ceramic capacitor (MLCC, dielectric layer thickness 0.5 μm, internal electrode layer thickness 0.3 μm) was fabricated by applying terminal electrodes to the chip.

[0054] In the obtained multilayer ceramic capacitor, the average area ratio of the area of ​​the co-material particles present to the total area of ​​the internal electrode layer in the cut surface obtained by cutting perpendicular to the lamination interface was 0.04. Furthermore, when the internal electrode layer was divided into three equal parts in the thickness direction at the center of the multilayer ceramic capacitor in the lamination direction, 85% of the co-material particles were present in the central part. Moreover, when the internal electrode layer was divided into three equal parts in the thickness direction at the center of the multilayer ceramic capacitor in the width direction, the variation in the area ratio of the co-material particles present in each of the five equal parts was 29%.

[0055] The resulting multilayer ceramic capacitor exhibited excellent continuity of the internal electrode layers.

[0056] (Example 2) <Preparation of barium titanate particles> An aqueous solution of barium hydroxide was kept at a temperature of 100°C, and a hydrated titanium oxide slurry was added to it. The mixture was reacted at 100°C for 30 minutes to obtain a barium titanate slurry. After the reaction, the obtained barium titanate slurry was filtered, washed with water, and dried at 130°C to obtain barium titanate particles. The obtained barium titanate particles had a crystallite diameter of 15 nm, a BET diameter of 20 nm, and a physical mean diameter of 15 nm obtained by electron microscopy observation.

[0057] <Preparation of Electrode Paste> Next, an electrode paste with the following composition was prepared. The component composition of the electrode paste was 45% by mass of nickel particles (physical mean diameter obtained by electron microscopy observation of 100 nm), 9.0% by mass of the obtained barium titanate particles, 2.8% by mass of vehicle, and 43.2% by mass of organic solvent (terpineol). The vehicle consisted of 13% by mass of ethyl cellulose (molecular weight 70,000) as a resin component and 87% by mass of terpineol as an organic solvent, and was prepared by heating to 60°C.

[0058] <Preparation of Multilayer Ceramic Capacitors> An electrode paste obtained was printed onto a dielectric sheet of barium titanate particles with a thickness of 0.5 μm. After drying, 20 layers were stacked, pressed together, and cut to produce chips measuring 3.2 mm x 1.6 mm. After debinding, these chips were fired at 1,260°C in a weakly reducing atmosphere. After firing, terminal electrodes were applied to the chips to produce multilayer ceramic capacitors (dielectric layer thickness 0.5 μm, internal electrode layer thickness 0.3 μm).

[0059] In the obtained multilayer ceramic capacitor, the average area ratio of the area of ​​the co-material particles present to the total area of ​​the internal electrode layer in the cut surface obtained by cutting perpendicular to the lamination interface was 0.05. Furthermore, when the internal electrode layer was divided into three equal parts in the thickness direction at the center of the multilayer ceramic capacitor in the lamination direction, more than 80% of the co-material particles were present in the central part. Moreover, when the internal electrode layer was divided into three equal parts in the thickness direction at the center of the multilayer ceramic capacitor in the width direction, and then divided into five equal parts at the width direction, the variation in the area ratio of the co-material particles present in each of the five divisions was within ±50% of the average value.

[0060] The resulting multilayer ceramic capacitor exhibited excellent continuity of the internal electrode layers.

[0061] (Example 3) Precursor titanium hydroxide of Example 2 (for details, TiO(OH) metatitanium) ２ Barium titanate particles and a multilayer ceramic capacitor using them were prepared in the same manner as in Example 1, except that the stirring speed during the addition of the titanium tetrachloride aqueous solution was further increased in the preparation of the colloidal solution.

[0062] (Example 4) Precursor titanium hydroxide of Example 1 (specifically, TiO(OH) metatitanium) ２In preparing the colloidal solution, a continuous process was used as follows: 100 g of barium hydroxide octahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to 240 mL of ultrapure water and dissolved in a pressure-resistant container under a nitrogen atmosphere at a liquid temperature of 90°C for 2 hours while stirring to prepare a barium solution for precursor preparation (particle raw material 1). 56.9 mL of an aqueous solution of titanium tetrachloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., titanium equivalent concentration: 16-17% by mass) was prepared (particle raw material 2). Particle raw materials 1 and 2 were placed in a container connected to a liquid transfer pump, and raw materials for which solute precipitation needed to be prevented were heated using a heating mechanism. Dispersions of barium titanate particles were continuously obtained from particle raw materials 1 and 2 at 60 mL / min and 14.24 mL / min, respectively, and a multilayer ceramic capacitor was fabricated using this dispersion in the same manner as in Example 1.

[0063] (Example 5) 3.4 g of a 50% by mass aqueous solution of titanium bis(ammonium lactate) dihydroxyl, 18.7 g of ultrapure water, and 5.6 g of barium hydroxide octahydrate were mixed, and then 2 mL of an 8 mol / L aqueous sodium hydroxide solution and 1.8 g of oleic acid were added to prepare a precursor solution. The prepared precursor solution was transferred to a PTFE (polytetrafluoroethylene) container, sealed in a pressure-resistant container, and heated to 230°C at a rate of 2°C / min while stirring. After being held at 230°C for 12 hours, it was cooled to room temperature. Ethanol was added to the reaction solution obtained in this way, and the supernatant was removed by centrifugation several times. After drying in an atmosphere at an ambient temperature of 90°C, barium titanate particles surface-modified with oleic acid were obtained, and a multilayer ceramic capacitor was fabricated using this solution in the same manner as in Example 1.

[0064] (Example 6) Barium titanate particles and a multilayer ceramic capacitor using them were produced in the same manner as in Example 3, except that the precursor titanium hydroxide colloid solution was added to the barium raw material solution without stirring.

[0065] (Comparative Example 1) A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that barium titanate particles were not added when preparing the electrode paste.

[0066] (Comparative Example 2) Precursor titanium hydroxide of Example 3 (specifically, TiO(OH) metatitanium) ２ Barium titanate particles and a multilayer ceramic capacitor using them were prepared in the same manner as in Example 1, except that the solvent was changed to pure water:diethylene glycol = 1:1 in the preparation of the colloidal solution.

[0067] <Continuity Evaluation> The continuity of the stacked MLCC was judged according to the following criteria: A: Cross-sectional scanning electron microscopy (SEM) observation shows that the electrodes maintain continuity in the layer direction and in-plane direction, with little to no defects or breaks observed. B: Cross-sectional SEM observation shows partial disturbances or defects in electrode continuity, but this does not impair the function of the MLCC in practical use. C: Cross-sectional SEM observation shows that the electrodes are discontinuous in most places, the connection in the layer direction or in-plane direction is not maintained, and the function of the MLCC in practical use is impaired.

[0068] The evaluation results are summarized in Table 1.

[0069]

[0070] As shown in Table 1, the multilayer ceramic capacitor of the example exhibited superior continuity of the internal electrode layer compared to the multilayer ceramic capacitor of the comparative example.

[0071] The disclosures of Japanese Patent Application No. 2025-068377, filed on 17 April 2025, and Japanese Patent Application No. 2026-039403, filed on 11 March 2026, are incorporated herein by reference in their entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A laminated ceramic component having a structure in which an internal electrode layer and a dielectric layer are alternately stacked after firing, wherein the average area ratio of the area of ​​existing co-material particles to the total area of ​​the internal electrode layer in a cleavage surface obtained by cutting the internal electrode layer perpendicular to the lamination interface is 0.0001 to 0.

15.

2. The laminated ceramic component according to claim 1, wherein in the internal electrode layer contained in the central part of the laminated ceramic component, the internal electrode layer is divided into three equal parts in the thickness direction, and 50% or more of the co-material particles are present in the central part.

3. The laminated ceramic component according to claim 1, wherein in the internal electrode layer contained in the center of the laminated ceramic component, the internal electrode layer is divided into three equal parts in the thickness direction, and in the central part, with an arbitrary point around the center of the laminated ceramic component as the center point, a length 25 times the thickness of the internal electrode layer is taken from there in the width direction, and this is divided into five equal parts in the width direction, the variation in the area ratio of the same material particles present in each of the five divided parts is within ±100% of the average value.

4. The multilayer ceramic component according to claim 1, wherein the thickness of the internal electrode layer is 500 nm or less.

5. An electrode paste for forming an internal electrode layer, comprising electrode particles and co-material particles, wherein the electrode particles are Ni particles or Cu particles, the co-material particles are barium titanate particles, and the mass ratio of the co-material particles to the total mass of the electrode particles is 1% by mass to 20% by mass.

6. The electrode paste according to claim 5, wherein the physical average diameter obtained by electron microscopy observation of the co-material particles is within the range of 1% to 25% of the physical average diameter obtained by electron microscopy observation of the electrode particles.

7. The electrode paste according to claim 5, wherein the crystallite size of the co-material particles is 1 nm to 20 nm, the BET diameter is 1 nm to 40 nm, and the physical average diameter obtained by electron microscopy observation is 1 nm to 40 nm.

8. The electrode paste according to claim 5, wherein the coefficient of variation of the physical diameter of the co-material particles is 0.5 or less.

9. The electrode paste according to claim 5, wherein the crystallite diameter / BET diameter value in the co-material particles is 0.5 to 1.

5.

10. The electrode paste according to claim 5, wherein the value of the crystallite size / physical average diameter obtained by electron microscope observation in the co-material particles is 0.5 to 1.

5.

11. Barium titanate particles, wherein the crystallite size / physical average diameter obtained by electron microscopy is 0.5 to 1.5.

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