Dielectric compositions and laminated ceramic electronic components

Abstract

A dielectric composition having dielectric particles comprising a perovskite-type compound and a first segregation comprising at least Ca, Al, Si and O.

Description

Technical Field

[0001] The present invention relates to dielectric compositions and laminated ceramic electronic components comprising the dielectric compositions. Background Technology

[0002] As shown in Patent Document 1, a stacked ceramic electronic component having a ceramic layer composed of a dielectric composition is known. In this stacked ceramic electronic component, defects such as cracks or fractures sometimes occur in the blank (base body) containing the dielectric composition. The main causes of these defects can be considered as bending of the mounting substrate, the difference in the coefficients of linear expansion between the ceramic layer and the internal electrode layer, or impacts or stresses applied to the blank from the outside. In particular, if the dielectric composition has low breaking toughness, corner defects or cracks may sometimes occur in the blank during tumbling in the manufacturing process.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2002 / 000568 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] The present invention was made in view of this actual situation, and its object is to provide a dielectric composition with high fracture toughness and a laminated ceramic electronic component comprising the dielectric composition.

[0008] Technical solutions for solving technical problems

[0009] To achieve the above objectives, the present invention provides a dielectric composition comprising:

[0010] Dielectric particles comprising perovskite-type compounds; and

[0011] The first segregation contains at least Ca, Al, Si, and O.

[0012] It is believed that in the dielectric composition of the present invention, the bonding strength between dielectric particles is improved by having a first segregation comprising a specified element. Furthermore, it is believed that even if a crack initiation occurs within the dielectric composition, the specified first segregation can suppress crack propagation. As a result, the dielectric composition of the present invention exhibits high breaking toughness.

[0013] Preferably, the molar ratio of Al to the total of Al and Si in the first segregation (Al / (Al+Si)) is 0.55 or more and 0.75 or less.

[0014] Preferably, the perovskite compound is represented as ABO3, where site A contains Ca and / or Sr, site B contains Zr and / or Ti, the molar ratio of Ca to site A is 0.5 or more per mole, and the molar ratio of Zr to site B is 0.8 or more per mole.

[0015] That is, the perovskite compound constituting the dielectric particles is more preferably calcium zirconate and / or calcium strontium zirconate than barium titanate. By using the above-mentioned perovskite compound as the main component of the dielectric composition, the effect of improving the breaking toughness strength caused by the first segregation can be further enhanced.

[0016] Preferably, the molar ratio of Ca to the total of Zr and Ti in the first segregation (Ca / (Zr+Ti)) is 1.50 or more, and the molar ratio (Ca / (Zr+Ti)) in the first segregation is higher than the molar ratio (Ca / (Zr+Ti)) in the dielectric particles.

[0017] Preferably, the dielectric composition further comprises a second segregation, which contains at least Ca, Si and O, and substantially does not contain Al.

[0018] The ratio of the total of Ca and Sr in the second segregation to the total of Zr and Ti is set as (Ca+Sr) / (Zr+Ti), and the ratio of Si in the second segregation to the total of Zr and Ti is set as Si / (Zr+Ti). Preferably, (Ca+Sr) / (Zr+Ti) is 1.15 or more in molar ratio and Si / (Zr+Ti) is 0.10 or more in molar ratio.

[0019] Preferably, the average particle size of the first segregation is 0.10 μm or more and 2.50 μm or less.

[0020] Preferably, in the cross-section of the dielectric composition described above, the content of the first segregation is 0.0005 particles / μm. 2 Above and 0.0100 per μm 2 the following.

[0021] The laminated ceramic electronic components comprising the dielectric composition of the present invention exhibit high durability against external stress and impact. That is, in the laminated ceramic electronic components of the present invention, defects such as cracks or fractures in the preform can be sufficiently suppressed. Attached Figure Description

[0022] Figure 1 This is a schematic diagram showing a cross-section of a multilayer ceramic capacitor according to one embodiment of the present invention.

[0023] Figure 2 It is Figure 1An enlarged cross-sectional view of the ceramic layer 10 shown.

[0024] Explanation of reference numerals in the attached figures

[0025] 2…Laminated ceramic capacitors

[0026] 4…Component Body

[0027] 4a…end face

[0028] 4b…side view

[0029] 10… Ceramic layer

[0030] 12…Inner Electrode Layer

[0031] 20…dielectric particles

[0032] 21…First Bias Analysis

[0033] 22…Second Separation

[0034] 23… Crystal boundary

[0035] 6…External Electrode Detailed Implementation

[0036] In this embodiment, as an example of the ceramic electronic component of the present invention, [the following is an example of the ceramic electronic component of the present invention]. Figure 1 The multilayer ceramic capacitor 2 shown will be described below. The multilayer ceramic capacitor 2 has an element body 4 and a pair of external electrodes 6 formed on the outer surface of the element body 4.

[0037] Figure 1 The component body 4 shown is typically roughly rectangular, having two opposite end faces 4a in the X-axis direction, two opposite side faces 4b in the Y-axis direction, and two opposite side faces 4b in the Z-axis direction. However, the shape of the component body 4 is not particularly limited, and it can also be elliptical cylinder, cylindrical, or other prismatic shapes. Furthermore, the external dimensions of the component body 4 are not particularly limited; for example, the length L0 in the X-axis direction can be set to 0.4 mm to 5.7 mm, the width W0 in the Y-axis direction to 0.2 mm to 5.0 mm, and the height T0 in the Z-axis direction to 0.2 mm to 3.0 mm. In this embodiment, the X-axis, Y-axis, and Z-axis are perpendicular to each other.

[0038] Furthermore, the component body 4 has a ceramic layer 10 and an internal electrode layer 12 that are substantially parallel to the plane containing the X and Y axes. Inside the component body 4, the ceramic layer 10 and the internal electrode layer 12 are alternately stacked in the Z-axis direction. Here, "substantially parallel" means that they are mostly parallel, but there may also be slightly non-parallel parts. The ceramic layer 10 and the internal electrode layer 12 may also be slightly uneven or tilted.

[0039] The ceramic layer 10 is composed of the dielectric composition described later. Furthermore, the average thickness (interlayer thickness) of each layer of the ceramic layer 10 is not particularly limited; for example, it can be set to 100 μm or less, preferably 30 μm or less. Additionally, the number of layers of the ceramic layer 10 is not particularly limited, as long as it is determined according to the desired characteristics. For example, it can be set to 20 layers or more, more preferably 50 layers or more.

[0040] On the other hand, the internal electrode layer 12 is stacked between each ceramic layer 10, and the number of stacked layers is determined according to the number of stacked ceramic layers 10. Furthermore, the average thickness of each layer of the internal electrode layer 12 is not particularly limited; for example, it can be set to 3.0 μm or less. Moreover, the average thickness of the ceramic layer 10 and the average thickness of the internal electrode layer 12 can be observed using a metal microscope, as shown below. Figure 1 The thickness of each layer (10, 12) can be calculated by measuring the thickness at at least 5 locations as shown in the cross-section.

[0041] Furthermore, the internal electrode layer 12 is stacked with two end faces 4a, one end of which is alternately exposed in the X-axis direction of the element body 4. Moreover, a pair of external electrodes 6 are each formed on one end face 4a of the element body 4 and electrically connected to the exposed ends of the alternately arranged internal electrode layers 12. By forming the internal electrode layer 12 and the external electrodes 6 in this way, a capacitor circuit is constructed using the external electrodes 6 and the internal electrode layer 12. That is, the ceramic layer 10 existing in the capacitance region is held by the internal electrode layers 12 with different polarities, enabling a voltage to be applied to the ceramic layer 10.

[0042] Preferably, the internal electrode layer 12 is made of a conductive material containing Ni as the main component. Specifically, the conductive material of the internal electrode layer 12 is preferably pure Ni or a Ni-based alloy containing 85 wt% or more Ni, and the Ni-based alloy may contain one or more elements selected from Mn, Cu, Cr, etc. In addition, in addition to the conductive material mentioned above, the internal electrode layer 12 may also contain particles of a perovskite-type compound having the same composition as the main component of the ceramic layer 10 as a common material. Furthermore, the internal electrode layer 12 may contain trace amounts (e.g., about 0.1 wt% or less) of non-metallic components such as S and P, and may also contain voids. Moreover, when the internal electrode layer 12 contains a common material or voids, sometimes an interruption portion without an electrode (conductive material) is formed in the internal electrode layer 12.

[0043] A pair of external electrodes 6 may include a sintered electrode layer, a resin electrode layer, a plated electrode layer, etc., and may be composed of a single electrode layer or multiple electrode layers stacked together. For example, the external electrode 6 may be configured as a three-layer structure of a sintered electrode layer, a Ni plated layer, and a Sn plated layer (stacked in the order described). In this case, the Sn plated layer is located on the outermost surface of the external electrode 6, thus the solder wettability of the external electrode 6 becomes good.

[0044] In addition, such as Figure 1 As shown, the external electrode 6 integrally has an end portion formed on the end face 4a in the X-axis direction of the element body 4, and an extension portion formed on the end of one of the four side faces 4b in the X-axis direction of the element body 4. That is, a pair of external electrodes 6 are respectively formed to extend from the end face 4a of the element body 4 to the side face 4b, and are insulated from each other in a manner that they do not contact each other in the X-axis direction.

[0045] Furthermore, the extension portion of the external electrode 6 is not necessary, and the external electrode 6 may be formed only by the end portion. Alternatively, when the multilayer ceramic capacitor 2 is mounted on the upper surface of the substrate, the extension portion of the external electrode 6 may be formed only on the side 4b at least opposite to the mounting surface of the substrate, or it may not be formed on the side 4b opposite to the mounting surface.

[0046] Next, the dielectric composition of the ceramic layer 10 will be described in detail.

[0047] The dielectric composition of the ceramic layer 10 comprises a perovskite-type compound represented by the general formula ABO3 as a main component. Here, the main component of the ceramic layer 10 (the main component of the dielectric composition) refers to the component that accounts for 80 mol% or more in the ceramic layer 10. Examples of perovskite compounds include barium titanate, calcium titanate, strontium titanate, calcium zirconate, strontium zirconate, and calcium strontium zirconate.

[0048] In this embodiment, the perovskite-type compound as the main component preferably satisfies the formula (Ca (1－α－β) Sr α Ba β ) m (Zr (1－γ－δ) Ti γ Hf δ O3. In the above composition formula, the symbols α, β, γ, δ, and m represent the element ratios, respectively.

[0049] m represents the element ratio of site A to site B, which can be set to a range of 1.0 to 1.1.

[0050] α represents the elemental ratio of Sr at site A, and β represents the elemental ratio of Ba at site A. In this embodiment, site A is preferably mainly composed of Ca and / or Sr. Specifically, the elemental ratio of Ca at site A (1-α-β) is preferably 0.5 to 1.0, more preferably 0.6 to 1.0. α is preferably 0 to 0.5, more preferably 0 to 0.4. β is preferably 0 to 0.2.

[0051] γ represents the elemental ratio of Ti to B sites, and δ represents the elemental ratio of Hf to B sites. In this embodiment, it is preferable that the B sites are mainly composed of Zr. Specifically, the elemental ratio of Zr in the B sites (1-γ-δ) is preferably 0.8 to 1.0 and less, more preferably 0.9 to 1.0 and less. γ is preferably 0 to 0.2 and less, more preferably 0 to 0.1 and less. Hf is usually an unavoidable impurity, and δ is preferably 0.03 and less.

[0052] Furthermore, the elemental ratio of oxygen (O) in the above composition can also deviate slightly from the stoichiometric composition.

[0053] In addition to the main components mentioned above, the ceramic layer 10 may also contain secondary components. Examples of secondary components include: Mn compounds, Mg compounds, Cr compounds, Ni compounds, rare earth element compounds, Si compounds, Li compounds, B compounds, V compounds, Al compounds, Ca compounds, etc. There are no particular limitations on the types, combinations, and amounts of secondary components.

[0054] In addition, the composition of the ceramic layer 10 can be analyzed by inductively coupled plasma optical emission spectrometry (ICP), laser ablation ICP mass spectrometry (LA-ICP-MS), fluorescence X-ray analysis (XRF), energy dispersive X-ray analysis (EDX), and electron probe microanalysis (EPMA) with wavelength dispersive X-ray spectrometer (WDS).

[0055] The ceramic layer 10 containing the above-mentioned components has Figure 2 The internal structure shown includes dielectric particles 20 as the parent phase, segregated phases (21, 22) with defined characteristics, and grain boundaries 23 located between the dielectric particles 20 in the ceramic layer 10.

[0056] The dielectric particles 20 are composed of the main component (perovskite-type compound) of the ceramic layer 10 described above. When the ceramic layer 10 contains secondary components, these secondary components may also be dissolved in the dielectric particles 20 in addition to the main component. Furthermore, the dielectric particles 20 may also have a core-shell structure due to the solid solution of secondary components. The average particle size of the dielectric particles 20 can be set to 1 μm or less, preferably 0.20 μm to 2.00 μm.

[0057] Furthermore, the average particle size of the dielectric particles 20 can be observed using scanning electron microscopy (SEM) or scanning transmission electron microscopy (STEM). Figure 2 The cross-section of the ceramic layer 10, as shown, is determined by image analysis of the obtained cross-sectional photograph. For example, the average particle size of the dielectric particles 20 can be calculated by measuring the equivalent circle diameter of at least five dielectric particles 20.

[0058] like Figure 2 As shown, the ceramic layer 10 in this embodiment includes a first segregation 21. The first segregation 21 is a phase containing at least Ca, Al, Si, and O (oxygen). Alternatively, the first segregation 21 may also contain, in addition to the aforementioned elements, the constituent elements of the ceramic layer 10 (elements such as Sr, Ba, Zr, Ti, Hf, etc., contained in the main components, and secondary component elements, etc.). By having the first segregation 21 containing Ca, Al, Si, and O (oxygen), the dielectric composition exhibits improved breaking toughness and strength, thus suppressing defects such as cracks or fractures in the ceramic layer 10.

[0059] The first partial analysis 21 can be determined by combining mapping analysis and point analysis performed via SEM-EDX or SEM-WDS. For example, in Figure 2 In the cross-section of the component body 4 as shown, mapping analysis is performed to determine the regions where Al and Si are repeatedly segregated, based on the mapping images of Al and Si. Here, "regions where Al and Si are repeatedly segregated" refers to regions where both Al and Si concentrations are high compared to the dielectric particles 20, which can be visually determined by aligning the mapping images of Al and Si.

[0060] After identifying the "region of repeated Al and Si segregation," point analysis is performed in this region to investigate whether Ca is present. Ca is a major component of the ceramic layer 10, and its presence in the region is influenced by the dielectric particles 20 surrounding it. Therefore, when investigating whether Ca is present in the region using EDX, the molar ratio of Ca to the total of Zr and Ti (Ca / (Zr+Ti)) is measured. Specifically, the Ca / (Zr+Ti) ratio in the region and the Ca / (Zr+Ti) ratio in the dielectric particles 20 are measured and compared. If the Ca / (Zr+Ti) ratio in the region is higher than that in the dielectric particles 20, it can be determined that Ca is present in the region, and this region can be identified as the first segregation 21 of this embodiment.

[0061] Furthermore, when performing compositional analysis with higher resolution than SEM using STEM or TEM, there is a possibility of determining the composition of the segregated phase without being affected by the dielectric particles 20 present around the segregated phase.

[0062] The first segregation 21, as determined by SEM-EDX or similar methods, preferably has a specified elemental ratio. Specifically, in the first segregation 21, the molar ratio of Al to the total of Al and Si (Al / (Al+Si)) is preferably 0.55 or more and 0.75 or less. Furthermore, when the total content of elements other than oxygen contained in the first segregation 21 is set to 100 moles, the sum of the contents of Al and Si is at least 20 mol% or more, preferably 30 mol% or more. In addition, the Ca / (Zr+Ti) ratio in the first segregation 21 is preferably 1.50 or more, more preferably 2.00 or more. Zr and Ti may also be substantially not included in the first segregation 21, therefore, the upper limit of the Ca / (Zr+Ti) ratio in the first segregation 21 is not particularly limited.

[0063] By satisfying the element ratio specified above through the first segregation 21, the breaking toughness of the dielectric composition is further improved.

[0064] The detailed composition of the first segregation 21 is not particularly limited, but the crystal system of the first segregation 21 is preferably tetragonal. As a tetragonal composite oxide containing Ca, Al and Si, Ca2Al (AlSiO7) can be cited as an example. By making the first segregation 21 a tetragonal composite oxide, the breaking toughness of the dielectric composition is further improved.

[0065] The average particle size of the first segregation 21 can be set to 4.0 μm or less, preferably in the range of 0.10 μm or more and 2.50 μm or less, and more preferably in the range of 0.10 μm or more and 1.0 μm or less. Furthermore, the average particle size of the first segregation 21 is preferably in the range of 0.1 to 0.9 times the average particle size of the dielectric particles 20. The average particle size of the first segregation 21 can be calculated by determining the equivalent circle diameter of the segregation after identifying at least five or more first segregations 21 using EDX or WDS, and then measuring the diameter of the segregation circle determined by image analysis.

[0066] In addition, in this embodiment, the number N1 of the first segregation per unit cross-sectional area of ​​the dielectric composition (unit: cells / μm) is used. 2 The content of the first segregation 21 in the dielectric composition (i.e., ceramic layer 10) is defined. This number N1 can be set to 0.0004 particles / μm. 2 The preferred value is 0.0005 particles / μm. 2 Above and 0.0100 per μm 2 Within the following range, it is more preferable to set it to 0.0007 particles / μm.2 Above, 0.0050 particles / μm 2 Below. Furthermore, the number N1 was determined by observing multiple fields of view using SEM or STEM. Figure 2 The cross-section of the ceramic layer 10 shown is measured to be at least 1000 μm in total. 2 The number of the first segregation 21 in the above cross section can be used for calculation.

[0067] By satisfying the above-mentioned suitable range in terms of the average particle size and content of the first segregation 21, the breaking toughness of the dielectric composition is further improved, and a high relative permittivity can be obtained.

[0068] Preferably, in the ceramic layer 10 of this embodiment, in addition to the first segregation 21, a second segregation 22 with defined characteristics is also present. This second segregation 22 is a phase comprising at least Ca, Si, and O (oxygen) of a composite oxide. Furthermore, unlike the first segregation 21, the second segregation 22 substantially does not contain Al. "Substantially does not contain Al" specifically means that the Al / (Al+Si) ratio in the second segregation 22 is 0.10 or less.

[0069] The second segregation 22, like the first segregation 21, can be determined using a combination of mapping and point analysis performed by SEM-EDX or SEM-WDS. In the analysis of the second segregation 22, the "Si segregation region" is determined based on the Si mapping image. The Si segregation region refers to the area where the Si concentration is higher than the Si concentration of the dielectric particles 20, and can be visually determined based on the Si mapping image.

[0070] After identifying the "Si segregation region," point analysis is performed within that region to determine the Al content and the Ca / (Zr+Ti) ratio. If the Al / (Al+Si) ratio in the identified region is below 0.10, and the Ca / (Zr+Ti) ratio in the identified region is higher than that of the dielectric particles 20, it can be determined that the identified region contains Ca and Si, but substantially does not contain Al. Therefore, the second segregation 22 contained in the ceramic layer 10 can be determined using the above method.

[0071] For the second segregation 22, compositional analysis can also be performed using STEM or TEM, which have higher resolution than SEM. In this case, it is possible to determine the composition of the second segregation 22 without being affected by the dielectric particles 20 present around the second segregation 22.

[0072] The second segregation 22 preferably has a predetermined element ratio. Specifically, the ratio of the total of Ca and Sr in the second segregation 22 to the total of Zr and Ti is set as (Ca+Sr) / (Zr+Ti), and the ratio of Si in the second segregation 22 to the total of Zr and Ti is set as Si / (Zr+Ti). The molar ratio of (Ca+Sr) / (Zr+Ti) in the second segregation 22 is preferably 1.15 or more, more preferably 1.39 or more. In addition, the molar ratio of Si / (Zr+Ti) in the second segregation 22 is preferably 0.10 or more, more preferably 0.20 or more. Zr and Ti may also be substantially not included in the second segregation 22, therefore, there is no particular limitation on the upper limit of (Ca+Sr) / (Zr+Ti) and the upper limit of Si / (Zr+Ti).

[0073] The detailed composition of the second segregation 22 is not particularly limited, but the crystal system of the second segregation 22 is preferably orthorhombic. As an orthorhombic composite oxide containing Ca and Si, Ca2SiO4 can be cited as an example.

[0074] By incorporating the second segregation 22, which has the aforementioned specified characteristics, together with the first segregation 21 into the dielectric composition, the breaking toughness of the dielectric composition is further improved.

[0075] Furthermore, the average particle size of the second segregation 22 can be set to 4.0 μm or less, preferably 0.1 μm to 2.5 μm. The average particle size of the second segregation 22 can be measured in the same manner as the average particle size of the first segregation 21. That is, after determining at least five or more second segregations 22 using the above method, the equivalent circle diameter of these second segregations 22 is measured by image analysis to calculate the average particle size.

[0076] Furthermore, the content of the second segregation 22 in the dielectric composition (i.e., ceramic layer 10) is the same as that of the first segregation 21, expressed as the number N2 of the second segregation 22 contained per unit cross-sectional area of ​​the dielectric composition (unit: cells / μm). 2 The number N2 is defined as follows: it can be measured in the same way as the number N1. In this embodiment, it is preferable to determine the content (number N2) of the second segregation 22 by taking into account the content (number N1) of the first segregation 21. Specifically, the ratio of N2 to N1 (N2 / N1) can be set in the range of 0.2 to 5.0, and preferably in the range of 0.5 to 2.0.

[0077] As described above, the ceramic layer 10 (dielectric composition) of this embodiment contains predetermined segregated phases (21, 22), which can improve the breaking toughness of the element body 4. Furthermore, in addition to the aforementioned segregated phases (21, 22), other segregated phases or voids may also exist in the ceramic layer 10. Additionally, the grain boundaries 23 existing between the dielectric particles 20 can be composed of the main component's constituent elements and secondary component elements, and other segregated phases may exist at these grain boundaries 23.

[0078] Next, the explanation Figure 1 An example of a method for manufacturing the multilayer ceramic capacitor 2 shown.

[0079] First, the manufacturing process of the component body 4 will be explained. In the manufacturing process of the component body 4, dielectric paste that will become ceramic layer 10 after firing and internal electrode paste that will become internal electrode layer 12 after firing are prepared.

[0080] The dielectric paste is manufactured using a powder of a perovskite-type compound (hereinafter referred to as the main component powder) that is the main component of the dielectric composition, and a first segregation powder that becomes the first segregation 21 after calcination. The main component powder can be manufactured by solid-state method, hydrothermal synthesis method, or sol-gel method, etc. For example, in the solid-state method, initial raw materials such as CaCO3 powder, SrCO3 powder, ZrO2 powder, and TiO2 powder are uniformly mixed by wet mixing or other methods, and then pre-calcined to obtain the main component powder. At this time, the pre-calcined main component powder may also be subjected to appropriate treatment such as pulverization and classification.

[0081] The first segregation powder is obtained by mixing Ca-containing compound powder (e.g., CaCO3 powder), Al-containing compound powder (e.g., Al2O3 powder), and Si-containing compound powder (e.g., SiO2 powder) in a specified ratio, and then performing a pre-calcination treatment. When preparing the first segregation powder, it is preferable to perform appropriate pulverization or the like to control the particle size of the first segregation 21.

[0082] Furthermore, when a second segregation 22 is formed in the ceramic layer 10, a second segregation powder can also be prepared. This second segregation powder, like the first segregation powder, can be manufactured by pre-firing a compound powder containing Ca and a compound powder containing Si. Alternatively, the second segregation 22 can sometimes be formed by adjusting the proportions of byproduct raw materials, even without preparing a second segregation powder.

[0083] The dielectric paste is obtained by adding the aforementioned main component powder and first segregation powder to an organic colorant and then mixing them. Here, the organic colorant is a material obtained by dissolving a binder in an organic solvent. The binder used is not particularly limited; for example, it can be appropriately selected from various binders such as polyvinyl butyral, acrylic acid, and ethyl cellulose. Similarly, the organic solvent used is not particularly limited; for example, it can be appropriately selected from various organic solvents such as methyl ethyl ketone, methanol, ethanol, acetone, toluene, terpineol, and butyl carbitol.

[0084] Furthermore, while the aforementioned dielectric paste is an organic coating, it can also be a water-based coating that combines a mixed powder and a water-based colorant. In this case, the water-based colorant is prepared by dissolving a water-soluble binder and dispersant in water. The water-soluble binder used is not particularly limited; for example, polyvinyl alcohol, water-soluble acrylic resin, or water-soluble polyvinyl butyral resin can be used. At this time, a second segregation powder and by-product raw materials are also appropriately added. Additionally, the dielectric paste may contain additives selected from the aforementioned second segregation powder, various dispersants, plasticizers, dielectrics, by-product compounds, glass frit, etc., as needed.

[0085] On the other hand, the internal electrode paste can be prepared by mixing conductive materials such as pure Ni powder or Ni alloy powder, or various oxides, organometallic compounds, and resinates that become Ni or Ni alloys after formal firing, with the aforementioned organic colorant. Alternatively, the main component powder contained in the dielectric paste can be added as a common material to the internal electrode paste. This common material helps to inhibit the sintering of the conductive powder during firing.

[0086] Next, the dielectric paste is sheeted using methods such as a scraper, thus obtaining a ceramic green sheet. Then, the internal electrode paste is applied onto the ceramic green sheet in a prescribed pattern using various printing or transfer methods such as screen printing. Furthermore, the green sheets with the internal electrode pattern formed are stacked in multiple layers and then stamped along the stacking direction, thus obtaining a master laminate. At this point, the ceramic green sheet and the internal electrode pattern are stacked with the ceramic green sheet located on the upper and lower surfaces of the master laminate in the stacking direction.

[0087] The master layer laminate obtained through the above processes is cut into specified dimensions by die-cutting or push-cutting to obtain multiple green chips. The green chips can be cured and dried as needed to remove plasticizers, etc. After curing and drying, they can be tumbling polished using a horizontal centrifugal tumbling mill or similar method. In tumbling polishing, the green chip, along with a grinding medium and polishing fluid, is placed into a tumbling container, which is then subjected to rotational motion or vibration. This tumbling polishing removes unwanted areas such as burrs generated during cutting, forming rounded corners (angle R) at the corners of the green chip. The tumbling polished green chips are then washed with a cleaning solution such as water and dried. Alternatively, this tumbling polishing can be performed after the green chips have been fired.

[0088] Next, the green sheet obtained above is subjected to debinding and firing treatment to obtain component body 4.

[0089] The conditions for the binder removal process can be appropriately determined based on the main component composition of the ceramic layer 10 and the internal electrode layer 12, and are not particularly limited. For example, it is preferable to set the heating rate to 5 to 300°C / hour, the holding temperature to 180 to 400°C, and the temperature holding time to 0.5 to 24 hours. In addition, the binder removal atmosphere is set to air or a reducing atmosphere.

[0090] The firing conditions can be appropriately determined based on the main component composition of the ceramic layer 10 and the main component composition of the internal electrode layer 12, and are not particularly limited. For example, the holding temperature during firing is preferably 1200–1350°C, more preferably 1220–1300°C, and the holding time is preferably 0.5–8 hours, more preferably 1–3 hours. Furthermore, the firing atmosphere is preferably a reducing atmosphere, and the atmosphere gas can be, for example, a humidified mixture of N2 and H2. Additionally, when the internal electrode layer 12 is composed of a base metal such as Ni or a Ni alloy, the oxygen partial pressure in the firing atmosphere is preferably set to 1.0 × 10⁻⁶. －14 ~1.0×10 －10 MPa.

[0091] In addition, annealing can be performed as needed after firing. Annealing is a treatment for re-oxidizing the ceramic layer 10, and it is preferable to perform annealing when firing is carried out in a reducing atmosphere. The conditions for annealing can be appropriately determined according to the main component composition of the ceramic layer 10, and there are no particular limitations. For example, it is preferable to set the holding temperature to 950-1150°C, the holding time to 0-20 hours, and the heating and cooling rates to 50-500°C / hour. Furthermore, as the atmosphere gas, humidified N2 gas or the like is preferred, and the oxygen partial pressure in the annealing atmosphere is preferably set to 1.0 × 10⁻⁶. -9 ~1.0×10-5 MPa.

[0092] In the aforementioned debinding, firing, and annealing processes, a wetting agent such as a wetter can be used to humidify the gas (N2) or a mixed gas. In this case, the water temperature is preferably around 5–75°C. Furthermore, the debinding, firing, and annealing processes can be performed continuously or independently.

[0093] Next, a pair of external electrodes 6 are formed on the outer surface of the element body 4 obtained above. The method for forming the external electrodes 6 is not particularly limited. For example, when forming a sintered electrode as the external electrode 6, it is sufficient to apply a conductive paste containing glass frit to the end face of the element body 4 by impregnation and then heat the element body 4 at a predetermined temperature. Alternatively, when forming a resin electrode as the external electrode 6, it is sufficient to apply a conductive paste containing thermosetting resin to the end face of the element body 4 and then heat the element body 4 at the temperature required for thermosetting resin curing. Furthermore, after forming the sintered electrode or resin electrode using the above methods, sputtering, vapor deposition, electroplating, or chemical plating (electrolytic plating) can be performed to form an external electrode 6 with a multilayer structure.

[0094] Through the above process, a multilayer ceramic capacitor 2 with external electrodes 6 is obtained.

[0095] (Summary of Implementation Methods)

[0096] The multilayer ceramic capacitor 2 of this embodiment has an element body 4, on which ceramic layers 10 made of a predetermined dielectric composition and internal electrode layers 12 are alternately stacked. Moreover, the dielectric composition of the ceramic layers 10 has dielectric particles 20 containing perovskite-type compounds and a first segregation 21 containing at least Ca, Al, Si and O.

[0097] The dielectric composition of the ceramic layer 10 exhibits improved breaking toughness due to the aforementioned characteristics. The reason for this improved breaking toughness is not yet clear, but it is believed that the bonding strength between dielectric particles is improved due to the first segregation 21 containing specified elements. Furthermore, it is assumed that even if a crack initiation occurs within the dielectric composition, the first segregation 21 can suppress crack propagation. In the multilayer ceramic capacitor 2 of this embodiment, the ceramic layer 10 is composed of a dielectric composition with high breaking toughness, thus sufficiently suppressing defects such as cracks or fractures in the element body 4. In addition, the multilayer ceramic capacitor 2 exhibits high durability against external stress and impact.

[0098] In particular, by controlling the element ratio (Al / (Al+Si), Ca / (Zr+Ti)), average particle size, and content (number N1) in the first segregation 21 within a specified range, the breaking toughness of the dielectric composition can be further improved, and a high relative permittivity can be obtained.

[0099] Furthermore, the ceramic layer 10 (dielectric composition) contains a second segregation 22 that comprises at least Ca, Si, and O but is substantially free of Al. This second segregation 22 further enhances the breaking toughness of the dielectric composition.

[0100] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments in any way, and various changes can be made without departing from the spirit of the present invention.

[0101] For example, in this embodiment, a multilayer ceramic capacitor 2 is used as an example of a multilayer ceramic electronic component, but the multilayer ceramic electronic component of the present invention may also be a bandpass filter, a multilayer three-terminal filter, a thermistor, a varistor, etc.

[0102] In this embodiment, the ceramic layer 10 and the internal electrode layer 12 are stacked in the Z-axis direction, but the stacking direction can also be the X-axis or Y-axis direction. In this case, it is sufficient to align the exposed surface of the internal electrode layer 12 and form the external electrode 6. Alternatively, the internal electrode layer 12 can be led out to the outer surface of the component body 4 via a through-hole electrode, in which case the through-hole electrode and the external electrode 6 are electrically bonded.

[0103] Example

[0104] The present invention will be further described below based on detailed embodiments, but the present invention is not limited to these embodiments.

[0105] (Experiment 1)

[0106] In Experiment 1, capacitor samples of Examples 1, 2 and Comparative Examples 1 to 4 were prepared in the following order.

[0107] Example 1

[0108] First, prepare the main component powder and the first segregation powder as raw materials for the dielectric paste. Specifically, the main component powder is set as (Ca) manufactured by a solid-state method. 0.7 Sr 0.3 (Zr) 0.96 Ti 0.04 On the other hand, the first segregation powder is obtained by wet mixing CaCO3 powder, Al2O3 powder and SiO2 powder in a specified ratio, pre-calcining and then pulverizing using a ball mill.

[0109] Next, a paste for dielectrics is obtained by mixing the main component powder, the first segregation powder, the organic colorant, and the secondary component powder (MnCO3 powder). Additionally, a paste for internal electrodes is obtained by mixing Ni powder and the organic colorant.

[0110] Next, using the aforementioned dielectric paste and internal electrode paste, a green sheet was manufactured using a sheet forming method. Then, the green sheet was subjected to debinding, firing, and annealing treatments to obtain a component body 4 with dimensions L0×W0×T0=3.25mm×1.75mm×1.75mm. Furthermore, in the obtained component body 4, the number of ceramic layers 10 sandwiched between the internal electrode layers 12 was set to 250, the average thickness of the ceramic layers 10 was set to 2.5μm, and the average thickness of the internal electrode layers 12 was set to 1.1μm. Through the above processes, a capacitor sample of Example 1 was obtained.

[0111] Example 2

[0112] In Example 2, barium titanate powder (BaTiO3 powder) manufactured by hydrothermal synthesis was used as the main component powder added to the dielectric paste. The experimental conditions of Example 2 were the same as those of Example 1, except that the main component of the ceramic layer 10 was changed to BaTiO3, and the capacitor sample of Example 2 was obtained.

[0113] Comparative Example 1

[0114] In Comparative Example 1, the first segregation powder was not used in the preparation of the dielectric paste. That is, the dielectric paste of Comparative Example 1 was prepared by mixing (Ca... 0.7 Sr 0.3 (Zr) 0.96 Ti 0.04 The sample was prepared by using O3 as the main component powder, secondary component powder (the same secondary component as in Example 1), and organic colorant. The experimental conditions for Comparative Example 1 were the same as those for Example 1, except as described above, and a capacitor sample of Comparative Example 1 was obtained.

[0115] Comparative Example 2

[0116] In Comparative Example 2, the first segregation powder was not used; instead, SiO2 powder was added to the dielectric paste. That is, the dielectric paste of Comparative Example 2 was prepared by mixing (Ca...) 0.7 Sr 0.3 (Zr) 0.96 Ti 0.04 The sample was prepared by using a main component powder composed of O3, SiO2 powder, secondary component powder (the same secondary component as in Example 1), and an organic colorant. The experimental conditions for Comparative Example 2 were the same as those for Example 1, except as described above, and a capacitor sample of Comparative Example 2 was obtained.

[0117] Comparative Example 3

[0118] In Comparative Example 3, the first segregation powder was not used; instead, a composite oxide powder was prepared by mixing Al₂O₃ powder and SiO₂ powder and pre-calcining it. In Comparative Example 3, this Al-Si-O composite oxide powder was mixed with (Ca... 0.7 Sr 0.3 (Zr) 0.96 Ti 0.04 A dielectric paste was prepared using a main component powder composed of O3, a secondary component powder (the same secondary component as in Example 1), and an organic colorant. The experimental conditions for Comparative Example 3 were the same as those for Example 1, except as described above, and a capacitor sample of Comparative Example 3 was obtained.

[0119] Comparative Example 4

[0120] In Comparative Example 4, similar to Example 2, barium titanate powder (BaTiO3 powder) manufactured by hydrothermal synthesis was prepared as the main component powder added to the dielectric paste. Furthermore, in Comparative Example 4, the first segregation powder was not used; instead, a composite oxide powder obtained by mixing and pre-calcining Al2O3 powder and SiO2 powder was prepared. The dielectric paste of Comparative Example 4 was prepared by mixing the main component powder composed of BaTiO3, the Al-Si-O composite oxide powder, the secondary component powder (the same secondary component as in Example 1), and an organic colorant. The experimental conditions for Comparative Example 4, other than those described above, were the same as in Example 1, and a capacitor sample of Comparative Example 4 was obtained.

[0121] The capacitor samples of each embodiment and comparative example in Experiment 1 were evaluated as shown below.

[0122] Analysis of segregation

[0123] In Experiment 1, the cross-sections of each capacitor sample were observed using SEM. Mapping and point analyses were then performed using EDX to determine the constituent elements of the segregated phases present within the ceramic layer 10. The measurement results for each embodiment and comparative example are shown in Table 1.

[0124] Drum grinding test

[0125] In Experiment 1, a tumbling test was conducted to evaluate the breaking toughness of the dielectric composition constituting the ceramic layer 10. Specifically, the fired component body, mullite balls as the medium, SiC abrasive, and water were placed in a tumbling chamber, which was rotatably arranged on the circumference of a turntable. Then, by rotating the turntable, each tumbling chamber rotated in the opposite direction to the turntable's revolution. That is, the tumbling chambers underwent planetary rotation. The test was conducted under two conditions: a tumbling time of 2 hours and a tumbling time of 8 hours. After drying the component body removed from the tumbling chamber, its appearance was examined using a stereomicroscope. The number of samples with defects such as cracks or corner defects on the component body was measured.

[0126] For each embodiment and comparative example, 100 samples were subjected to a tumbling test with a grinding time of 2 hours and 100 samples were subjected to a tumbling test with a grinding time of 8 hours, and the defect rate was measured. When the defect rate was 0% under the 2-hour grinding time condition, the breaking toughness was judged to be "sufficient (acceptable)"; when the defect rate was 0% under the 8-hour grinding time condition, the breaking toughness was judged to be "better". The test results for each embodiment and comparative example are shown in Table 1.

[0127] Table 1

[0128]

[0129] As shown in Table 1, in Example 1 where the first segregation 21 of the Ca-Si-Al-O system is present, the defect rate in the tumble grinding test can be reduced compared to Comparative Examples 1 to 3. Similarly, in Example 2 where the first segregation 21 of the Ca-Si-Al-O system is present, the defect rate in the tumble grinding test can be reduced compared to Comparative Example 4. Based on these results, it can be seen that by incorporating the first segregation 21 of the Ca-Si-Al-O system into the dielectric composition (ceramic layer), the breaking toughness of the dielectric composition can be improved, and defects in the capacitor sample caused by external impacts can be suppressed.

[0130] Furthermore, as shown in Table 1, the results show that the defect rate was lower in Example 1 under the grinding time of 8 hours compared to Example 2. Based on these results, it can be concluded that the breaking toughness of the dielectric composition can be further improved by forming a first segregation 21 on the main component of the calcium zirconate system.

[0131] Experiment 2

[0132] In Experiment 2, capacitor samples from Examples 10-16 with different elemental ratios of the first segregation 21 (Al / (Al+Si) and Ca / (Zr+Ti)) were prepared. The elemental ratio of the first segregation 21 was controlled by adjusting the proportions of the starting materials (CaCO3 powder, Al2O3 powder, SiO2 powder) during the manufacture of the powder for the first segregation. Furthermore, the elemental ratio of the first segregation 21 in each of Examples 10-16 was determined by SEM-EDX. The experimental conditions in Experiment 2, other than those described above, were the same as those in Example 1 of Experiment 1. The evaluation results of Examples 10-16 of Experiment 2 are shown in Table 2.

[0133] Table 2

[0134]

[0135] According to the evaluation results of Examples 10-14 shown in Table 2, the Al / (Al+Si) of the first segregation 21 is preferably in the range of 0.55 or more and 0.75 or less. Furthermore, according to the evaluation results of Examples 15 and 16 shown in Table 2, the Ca / (Zr+Ti) of the first segregation 21 is preferably 1.50 or more.

[0136] Experiment 3

[0137] In Experiment 3, capacitor samples from Examples 20-24 with different average particle sizes of the first segregation 21 and Examples 25-28 with different contents (number N1) of the first segregation 21 were prepared. The average particle size of the first segregation 21 was controlled according to the grinding conditions when grinding the powder for the first segregation using a ball mill. The contents of the first segregation 21 were controlled according to the proportion of the powder for the first segregation in the dielectric paste. In addition, the average particle size and contents of the first segregation 21 were determined using SEM-EDX by the method shown in the embodiment. The experimental conditions in Experiment 3 other than those described above were set to be the same as those in Example 1 of Experiment 1.

[0138] Furthermore, in Experiment 3, a Cu-containing sintered electrode layer, a Ni-plated layer, and a Sn-plated layer were formed on the outer surface of the component body in the order described. The relative permittivity of the capacitor samples of each embodiment was also measured. The relative permittivity was calculated by measuring the electrostatic capacitance using an LCR meter (KEYSIGHT TECHNOLOGIES: E4981A capacitance meter). Specifically, in the electrostatic capacitance measurement, the measurement temperature was set to 20°C, and a signal with a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms was input to the capacitor sample. The relative permittivity (unitless) was calculated based on the thickness of the dielectric layer, the effective electrode area, and the measured electrostatic capacitance. Furthermore, for each embodiment, the above measurements were performed on 10 samples, and their average values ​​were calculated. A relative permittivity of 30 or higher was considered good. The evaluation results of Examples 20-28 of Experiment 3 are shown in Table 3.

[0139] Table 3

[0140]

[0141] According to the evaluation results of Examples 20-24 shown in Table 3, the average particle size of the first segregation 21 is preferably 0.10 μm or more and 2.50 μm or less. Furthermore, according to the evaluation results of Examples 25-28 shown in Table 3, the content (number N1) of the first segregation 21 is preferably 0.0005 particles / μm. 2 Above and 0.0100 per μm 2 the following.

[0142] Experiment 4

[0143] In Experiment 4, a second segregation powder was prepared by mixing and pre-calcining CaCO3 powder and SiO2 powder. This second segregation powder was then added together with the first segregation powder to a dielectric paste to obtain capacitor samples of Examples 31 and 32. The experimental conditions for Experiment 4, except as described above, were the same as those for Example 22 of Experiment 3.

[0144] In addition, in Experiment 4, the grinding time for the tumble grinding test was extended compared to Experiments 1-3, and the test was also conducted with a grinding time of 16 hours. With a defect rate of 0% after 16 hours of grinding, the breaking toughness strength was judged to be "particularly good". The evaluation results of Examples 31 and 32 of Experiment 4 are shown in Table 4. Furthermore, Table 4 also shows the evaluation results of Example 22 of Experiment 3, which does not contain the second segregation 22, along with the results of Examples 31 and 32 containing the second segregation 22.

[0145] Table 4

[0146]

[0147] As shown in Table 4, the evaluation results indicate that the dielectric composition, in addition to having a first segregation 21, also possesses a second segregation 22 that is Al-free and based on a Ca-Si-O system, further enhancing the breaking toughness. Furthermore, it is known that in the second segregation 22, the (Ca+Sr) / (Zr+Ti) ratio is preferably 1.15 or higher, and the Si / (Zr+Ti) ratio is 0.10 or higher. Moreover, in Examples 31 and 32, the Al / (Al+Si) ratio of the second segregation 22 is less than 0.10, indicating that the second segregation 22 substantially does not contain Al.

Claims

1. A dielectric composition characterized in that, having: a dielectric particle including a perovskite compound; and a first segregation including at least Ca, Al, Si, and O, the perovskite compound is represented by ABO3, the A site includes Ca or / and Sr, and the B site includes Zr or / and Ti, the molar ratio of Ca with respect to 1 mole of the A site is 0.5 or more, the molar ratio of Zr with respect to 1 mole of the B site is 0.8 or more.

2. The dielectric composition according to claim 1, characterized in that: in the first segregation, the molar ratio of Al with respect to the total of Al and Si, Al / (Al+Si), is 0.55 or more and 0.75 or less.

3. The dielectric composition according to claim 1 or 2, characterized in that: in the first segregation, the molar ratio of Ca with respect to the total of Zr and Ti, Ca / (Zr+Ti), is 1.50 or more, the molar ratio of Ca / (Zr+Ti) in the first segregation is higher than the molar ratio of Ca / (Zr+Ti) in the dielectric particle.

4. The dielectric composition according to claim 1 or 2, characterized in that: the average particle diameter of the first segregation is 0.10 μm or more and 2.50 μm or less.

5. The dielectric composition according to claim 1 or 2, characterized in that: The first segregation has a content of 0.0005 / μm 2 Above and 0.0100 / μm 2 Below.

6. A dielectric composition characterized by, having: a dielectric particle including a perovskite compound; and a first segregation including at least Ca, Al, Si, and O, the dielectric composition further has a second segregation, the second segregation includes at least Ca, Si, and O, and substantially does not include Al.

7. The dielectric composition according to claim 6, characterized in that: the ratio of the total of Ca and Sr with respect to the total of Zr and Ti in the second segregation is set as (Ca+Sr) / (Zr+Ti), the ratio of Si with respect to the total of Zr and Ti in the second segregation is set as Si / (Zr+Ti), (Ca+Sr) / (Zr+Ti) is 1.15 or more in terms of molar ratio, and Si / (Zr+Ti) is 0.10 or more in terms of molar ratio.

8. The dielectric composition according to claim 6, characterized in that: The first segregation has a content of 0.0005 / μm 2 Above and 0.0100 / μm 2 Below.

9. The dielectric composition according to claim 8, characterized in that: in the first segregation, the molar ratio of Al with respect to the total of Al and Si, Al / (Al+Si), is 0.55 or more and 0.75 or less.

10. A laminated ceramic electronic component, characterized by: including the dielectric composition according to any one of claims 1 to 9.

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