Dielectric ceramic composition and laminated ceramic electronic component

Abstract

The present invention provides a dielectric ceramic composition having: first crystal particles (41) having a perovskite structure represented by general formula ABO3, and having a core part (411) and a shell part (412) covering the core part (411) and containing a rare earth element and manganese; and second crystal particles (42) containing, as a main component, a barium titanate-based composite oxide in which the elemental ratio of barium to titanium is 0.70 or less.

Description

Technical Field

[0001] The present invention relates to a dielectric ceramic composition and a multilayer ceramic electronic component. Background Art

[0002] Multilayer ceramic electronic components such as multilayer ceramic capacitors (MLCCs) are used in high-frequency communication systems such as mobile phones.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-131669

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2016-153359 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] In recent years, the use of multilayer ceramic electronic components has expanded to electronic circuits that are related to human life, such as in-vehicle electronic control devices. These components are required to have both high reliability and, from the perspective of supply volume, higher mass productivity.

[0009] The dielectric ceramic composition used in the dielectric layers of multilayer ceramic electronic components utilizes a sintered core-shell structure with a barium titanate core surrounded by a shell formed by solid-solutions of various additives. This structure allows barium titanate, which exists at around 125°C, to exhibit high capacitance near its Curie temperature, where it transitions from a ferroelectric phase to a paraelectric phase. The various additives in the shell shift the temperature to a lower temperature, enabling designs with further increased capacitance within the practical temperature range of around room temperature.

[0010] The core-shell structure is believed to be formed by various additives dissolved in barium titanate. This is thought to occur when, for example, the components added as additives to the main component, barium titanate particles, react during firing at temperatures between 1000°C and 1400°C. Generally, as the firing temperature increases, the additives dissolve, and the shell becomes thicker. Therefore, precise control of the firing temperature is necessary to maintain the capacitance of multilayer ceramic electronic components within the desired range.

[0011] As an application example of barium titanate without a core-shell structure, a piezoelectric ceramic is disclosed, wherein as a barium titanate composite oxide, Ba4Ti 12 O 27 or Ba6Ti 17 O 40At least one of the above further contains 0.04 mass % to 0.20 mass % manganese based on the metal conversion relative to the barium titanate (for example, see Patent Document 1).

[0012] Also disclosed is a piezoelectric ceramic, wherein (Ba 1－x Ca x ) a (Ti 1－y Zr y )O3 (wherein, 0.09≤x≤0.30, 0.025≤y≤0.085, 0.986≤a≤1.020.) and 0.04 weight part or more and 0.36 weight part or less of manganese in terms of metal conversion per 100 weight parts of the metal oxide, as a barium titanate composite oxide, containing BaTi2O5, BaTi4O9, BaTi5O 11 、BaTi6O 13 、BaTi7O 14 、BaTi8O 16 、Ba2Ti5O 12 、Ba2Ti6O 13 、Ba2Ti9O 20 、Ba4Ti 11 O 26 、Ba4Ti 13 O 30 , CaTi2O4, CaTi2O5, CaTi4O9, Ca2Ti5O 12 、CaZr4O9、Ca2Zr7O 16 、Ca6Zr 19 O 44 , CaZrTi2O7 and Ca2Zr5Ti2O 16 At least one metal oxide (see, for example, Patent Document 2).

[0013] Attempts to apply the piezoelectric ceramics disclosed in Patent Documents 1 and 2 to dielectric ceramic compositions used in the dielectric layers of multilayer ceramic electronic components revealed that, as disclosed in Patent Documents 1 and 2, the maximum grain size of the crystal particles was found to be 2 μm or larger. In multilayer ceramic electronic components with dielectric layers of 10 μm or smaller, the number of grain boundaries decreased, significantly degrading insulation properties. Furthermore, the maximum heating rate during firing of these piezoelectric ceramics was 10°C / min, making it impossible to achieve the high mass productivity required for multilayer ceramic electronic components.

[0014] In recent years, the applications of dielectric ceramic compositions and multilayer ceramic electronic components have expanded, leading to demands for higher mass productivity. To achieve this, shorter firing times are required. Therefore, it is necessary to suppress capacitance changes caused by firing temperature and reduce temperature-related capacitance fluctuations.

[0015] The present invention has been made in view of the above-mentioned technical problems, and an object of the present invention is to provide a dielectric ceramic composition and a multilayer ceramic electronic component capable of suppressing capacitance variation due to firing temperature.

[0016] Technical solutions to technical problems

[0017] The dielectric ceramic composition of the present invention comprises: first crystal particles having a perovskite structure represented by the general formula ABO3, comprising a core portion and a shell portion covering the core portion and containing a rare earth element and manganese; and second crystal particles containing as a main component a barium titanate-based composite oxide having an elemental ratio of barium to titanium of 0.70 or less.

[0018] In the dielectric ceramic composition, the rare earth element may be at least one selected from the group consisting of gadolinium, europium, terbium, dysprosium, holmium, erbium, and ytterbium.

[0019] In the dielectric ceramic composition, the element ratio of barium to titanium is 0.926 to 0.995, the element ratio of the rare earth element to titanium is 0.005 to 0.05, and the element ratio of manganese to titanium can be 0.002 to 0.05.

[0020] The dielectric ceramic composition may further include silicon at an element ratio of 0.002 to 0.05 inclusive relative to titanium and magnesium at an element ratio of 0.00 to 0.05 inclusive relative to titanium.

[0021] In the dielectric ceramic composition, the concentrations of the rare earth element and manganese in the shell portion may be greater than the concentrations of the rare earth element and manganese in the core portion.

[0022] In the dielectric ceramic composition, the maximum particle size of the first crystal particles may be 2 μm or less.

[0023] In the dielectric ceramic composition, an element ratio of barium to titanium in the second crystal particles may be 0.16 or greater.

[0024] In the dielectric ceramic composition, the second crystal particles may be selected from BaTi2O5, BaTi4O9, BaTi5O 11 、BaTi6O 13 、Ba4Ti 11 O 26、Ba4Ti 12 O 27 、Ba4Ti 13 O 30 or Ba6Ti 17 O 40 At least one of the following.

[0025] In the dielectric ceramic composition, the second crystal grains may contain manganese, and an element ratio of manganese to titanium in the second crystal grains may be 0.02 to 0.10.

[0026] In the dielectric ceramic composition, the second crystal grains may contain manganese, and an element ratio of manganese to titanium in the second crystal grains may be 0.02 to 0.05.

[0027] Another dielectric ceramic composition according to the present invention comprises: first crystal particles having a perovskite structure represented by the general formula ABO3, and having a core portion and a shell portion covering the core portion and containing a rare earth element and manganese; and second crystal particles comprising Ba4Ti 11 O 26 The barium titanate-based composite oxide shown contains manganese, and the element ratio of manganese to titanium is 0.02 or more and 0.10 or less.

[0028] In the dielectric ceramic composition, the rare earth element may be at least one selected from the group consisting of gadolinium, europium, terbium, dysprosium, holmium, erbium, and ytterbium.

[0029] In the dielectric ceramic composition, the element ratio of barium to titanium is 0.926 to 0.995, the element ratio of the rare earth element to titanium is 0.005 to 0.05, and the element ratio of manganese to titanium can be 0.002 to 0.05.

[0030] The dielectric ceramic composition may further include silicon at an element ratio of 0.002 to 0.05 inclusive relative to titanium and magnesium at an element ratio of 0.00 to 0.05 inclusive relative to titanium.

[0031] In the dielectric ceramic composition, the concentrations of the rare earth element and manganese in the shell portion may be greater than the concentrations of the rare earth element and manganese in the core portion.

[0032] In the dielectric ceramic composition, the maximum particle size of the first crystal particles may be 2 μm or less.

[0033] In the dielectric ceramic composition, an element ratio of manganese to titanium in the second crystal particles may be 0.02 to 0.05.

[0034] The multilayer ceramic electronic component according to the present invention uses any of the above-mentioned dielectric ceramic compositions.

[0035] The multilayer ceramic electronic component comprises: a plurality of internal electrodes facing each other; a dielectric layer interposed between the plurality of internal electrodes and containing the dielectric ceramic composition according to claim 1; and external electrodes electrically connected to the internal electrodes.

[0036] Effects of the Invention

[0037] The present invention can provide a dielectric ceramic composition and a multilayer ceramic electronic component capable of suppressing capacitance variation due to firing temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a diagram illustrating the dielectric ceramic composition according to the first embodiment.

[0039] Figure 2 is a diagram illustrating a unit cell.

[0040] Figure 3 This is a diagram illustrating a method for confirming a core-shell structure.

[0041] Figure 4 This is a partial cross-sectional perspective view of a multilayer ceramic capacitor.

[0042] Figure 5 yes Figure 4 A-A line cross-section diagram.

[0043] Figure 6 yes Figure 4 BB line cross-section diagram.

[0044] Figure 7 This is a diagram illustrating the flow of a method for manufacturing a multilayer ceramic capacitor.

[0045] Figure 8 (a) and (b) are diagrams illustrating the internal electrode forming process.

[0046] Figure 9 This is a diagram illustrating a crimping process.

[0047] Figure 10 This is a diagram illustrating a side edge portion. DETAILED DESCRIPTION

[0048] Hereinafter, embodiments will be described with reference to the drawings.

[0049] (First embodiment)

[0050] like Figure 1As illustrated, the dielectric ceramic composition according to the first embodiment is a ceramic polycrystal containing crystal particles having a perovskite structure represented by the general formula ABO3. Within these ceramic polycrystals, at least one first crystal particle 41 has a core-shell structure, and at least one second crystal particle 42 has a barium to titanium element ratio of 0.70 or less.

[0051] The first crystal particle 41 has a roughly spherical core 411 and a shell 412 that surrounds the core 411. The core 411 is a crystalline portion in which the additive compound is not solid-dissolved or the amount of the additive compound dissolved is small. The shell 412 is a crystalline portion in which the additive compound is solid-dissolved and has a higher concentration of the additive compound than the concentration of the additive compound in the core 411. In this embodiment, the shell 412 contains rare earth elements and manganese. The rare earth element is not particularly limited and is at least one selected from gadolinium, europium, terbium, dysprosium, holmium, erbium, and ytterbium. In addition, the element concentrations of the rare earth elements and manganese in the shell 412 are greater than the element concentrations of the rare earth elements and manganese in the core 411.

[0052] Since the dielectric ceramic composition according to the present embodiment includes the first crystal particles 41 and the second crystal particles 42 , changes in capacitance due to firing temperature can be suppressed.

[0053] For example, when observing a cross section of the dielectric ceramic composition within a field of view in which a total of 400 or more first crystal grains 41 and second crystal grains 42 can be identified, the area ratio of the first crystal grains 41 is from 50% to 99.95%, and the area ratio of the second crystal grains 42 is from 0.05% to 50%.

[0054] Furthermore, the dielectric ceramic composition may contain, in addition to first crystal grains 41 and second crystal grains 42, third crystal grains 43 having a different composition or crystal structure from these, voids 44, and the like. For example, when observing a cross-section of the dielectric ceramic composition within a field of view in which a total of 400 or more first crystal grains 41, second crystal grains 42, and third crystal grains 43 are observed, the area ratio of third crystal grains 43 is 0.05% to 20%.

[0055] The first crystal particles 41 mainly contain crystal particles having a perovskite structure. Figure 2The unit cell is shown in FIG. In this unit cell, there are A sites located at the vertices of the crystal lattice, O sites located at the face centers of the crystal lattice, and B sites located within the octahedron with the O sites as vertices. In the perovskite structure, the A sites are occupied by alkaline earth metals such as barium (Ba), strontium (Sr), and calcium (Ca) that can obtain divalent cations, and the B sites are occupied by metal atoms such as hafnium (Hf), zirconium (Zr), and titanium (Ti) that can obtain tetravalent cations.

[0056] The perovskite structure also allows deviations from the stoichiometric composition. That is, the ratio of the A-site element to the B-site element does not have to be 1:1, and defects can be generated within a range that can maintain the perovskite structure. In addition, oxygen defects can also be generated. For example, in the formation of the composition formula A α BO 3－β When , a composition in the range of 0.98≤α≤1.01 and 0≤β≤0.20 is allowed.

[0057] However, for example, due to the generation of oxygen defects, the resistivity is reduced, or ion conductivity is shown, thereby reducing the electrical life when used as a stacked ceramic capacitor, or increasing the dielectric loss, and sometimes it cannot be used in practice. Therefore, for the first crystalline particles 41 having a perovskite structure, as needed, at least one of scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn) can also be contained as the first transition element. Thus, it is possible to increase the resistivity, increase the electrical life, or reduce the dielectric loss relative to the electrostatic capacitance.

[0058] Furthermore, if necessary, the first crystal particles 41 may contain at least one of the second transition elements yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), and silver (Ag). This can increase the resistivity, improve the electrical life, or reduce the dielectric loss relative to the capacitance.

[0059] Furthermore, if necessary, the first crystal grains 41 may contain at least one of the third transition elements lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au). This can improve resistivity, increase electrical life, and / or reduce dielectric loss relative to capacitance.

[0060] For example, in dielectric ceramic compositions, it is preferable to add titanium in an amount of 0.5 mol to 8.0 mol, calculated as titanium oxide (TiO2), per 100 mol of barium titanate, so that the Ba / Ti element ratio (x), representing the elemental ratio of barium to titanium, reaches 0.926 ≤ x ≤ 0.995. Compared to the case where no titanium-containing additive is added, the solid solution reaction in the barium titanate crystal particles can be relatively suppressed. This effect, for example, can be applied to multilayer ceramic capacitors requiring high mass production, enabling shorter firing times and suppressing the rate of change in capacitance due to changes in firing temperature, thus achieving high mass production.

[0061] Furthermore, it is more preferable to add titanium (calculated as titanium oxide (TiO2) in an amount of 2.0 mol to 6.4 mol per 100 mol of barium titanate) to the dielectric composition so that the Ba / Ti element ratio x is 0.940 ≤ x ≤ 0.980. In this case, a sufficient amount of second crystal particles 42 can be generated in the dielectric ceramic composition, and the fluctuation range of the electrostatic capacitance caused by changes in the firing temperature can be further suppressed.

[0062] As the above-mentioned titanium-containing additive, titanium oxide is preferably used as an example, but titanium hydroxide (Ti(OH) 4 ), titanium chloride (TiCl 4 ), titanium carbide (TiC), titanium sulfide (TiS 2 ) and the like can also be used.

[0063] Furthermore, it is further preferred that the dielectric ceramic composition contain 0.25 mol or more and 2.5 mol or less of gadolinium in terms of gadolinium oxide (Gd2O3) per 100 mol of barium titanate, so that the Gd / Ti element ratio y, which is the element ratio of the rare earth element, such as gadolinium, to the titanium content, is 0.005≤y≤0.05.

[0064] In addition to gadolinium oxide, it is preferred to add 0.2 mol to 5.0 mol of manganese in terms of manganese oxide (MnO) per 100 mol of barium titanate so that the Mn / Ti element ratio z, which is the element ratio of manganese to titanium content, becomes 0.002≤z≤0.05.

[0065] For example, when the conditions 0.926 ≤ x ≤ 0.995, 0.005 ≤ y ≤ 0.05, and 0.002 ≤ z ≤ 0.05 hold, the added gadolinium, manganese, and titanium react on the surface of the barium titanate crystal particles, forming a composite perovskite compound, believed to be Gd(Ti,Mn)O3, as a shell. This results in a dielectric ceramic composition that not only minimizes capacitance fluctuations due to firing temperature fluctuations but also inhibits the migration of oxygen defects within grain boundaries and the shell, suppressing resistivity reduction and improving electrical life.

[0066] Furthermore, it is more desirable to adjust the gadolinium and manganese amounts so as to satisfy 0.005 ≤ y ≤ 0.02 and 0.005 ≤ z ≤ 0.02. In this case, excessive solid dissolution of excess gadolinium into crystal particles formed from barium titanate and precipitation of excess manganese on the surface of the dielectric ceramic composition can be suppressed, thereby further reducing the magnitude of capacitance fluctuations due to firing temperature changes and maintaining a high resistivity.

[0067] In addition to the additives containing gadolinium, manganese, and titanium, silicon (calculated as silicon oxide (SiO2) in an amount of 0.2 mol to 5.0 mol) can be added to achieve a Si / Ti element ratio (a) of 0.002 ≤ a ≤ 0.05. Magnesium (calculated as magnesium oxide (MgO) in an amount of 0 mol to 5.0 mol) can also be added to achieve a Mg / Ti element ratio (b) of 0.00 ≤ b ≤ 0.05. In this case, the dielectric ceramic composition forms first crystal grains 41 containing silicon or second crystal grains 42, which are glass particles. During firing, a liquid phase forms within the composition, allowing for a dense ceramic to be obtained at a lower temperature. Furthermore, the addition of magnesium oxide allows for the formation of a shell in the form of Gd(Mg,Ti,Mn)O3 or (Gd,Ba)(Mg,Ti,Mn)O3, further suppressing the migration of oxygen defects within the grain boundaries and the shell, thereby reducing the decrease in resistivity.

[0068] In this case, the excess additives can be prevented from being generated as the third crystal particles 43, the relative dielectric constant can be prevented from decreasing, and the densification effect at low temperatures and / or the decrease in resistivity can be suppressed.

[0069] In addition, by using cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium as rare earth elements among the first transition metal element, the second transition metal element, and the third transition metal element, the rare earth elements can be dissolved from the interface to the interior of the first crystal particles 41 in the firing temperature range of 1000°C to 1400°C for obtaining the dielectric ceramic composition, thereby obtaining crystal particles having a core-shell structure with a shell portion and a core portion.

[0070] However, in a core-shell structure, as the firing temperature increases, various additives generally dissolve more in the crystal particles formed by barium titanate, resulting in a tendency for the shell to become thicker. In the shell, the high capacitance region near the Curie temperature of barium titanate, around 125°C, is close to room temperature. As a result, the capacitance in the practical temperature range around room temperature varies significantly depending on the thickness of the shell. Therefore, as an example, precise control of the firing temperature is required to keep the capacitance of multilayer ceramic capacitors within the required range.

[0071] The dielectric ceramic composition according to the present embodiment can be obtained by firing at 1000° C. to 1300° C. and by setting the temperature rise rate during the firing process to a rapid temperature rise rate of 3000° C. / h to 10000° C. / h.

[0072] The first crystal particles 41, each having a core-shell structure and having a shell 412 containing a rare earth element and manganese, are formed through a different process than conventional core-shell structures. Specifically, the rare earth element not only dissolves into the barium titanate crystal particles, but the added rare earth element, manganese, and titanium react on the surface of the barium titanate crystal particles, forming a composite perovskite compound such as Gd(Ti,Mn)O3 as the shell.

[0073] In addition, the shell portion 412 can further react with the added magnesium on the surface of the barium titanate crystal particles to form a composite perovskite compound such as Gd(Mg, Ti, Mn)O 3 as the shell portion.

[0074] Furthermore, the shell portion 412, which is believed to be in the form of a composite perovskite compound of Gd(Ti,Mn)O3 or Gd(Mg,Ti,Mn)O3, can also be generated in the form of (Gd,Ba)(Ti,Mn)O3 or (Gd,Ba)(Mg,Ti,Mn)O3 as a shell portion by reacting with barium titanate crystal particles as the main component of the surrounding area.

[0075] For example, the core portion 411 of the core-shell structure is primarily composed of crystal particles formed of barium titanate and may also contain added rare earth elements, manganese, magnesium, etc. However, for example, the shell portion 412 may contain a relatively larger amount of the rare earth elements, manganese, magnesium, etc. among the additives than the core portion 411.

[0076] More specifically, the core-shell structure of the crystalline particles, primarily composed of barium titanate and having a shell containing gadolinium and manganese, is defined as follows: At any point within a range of 10% of the particle diameter from the surface to the center, the ratio of gadolinium or manganese to titanium is relatively high compared to the center. The presence of these core-shell crystalline particles allows the polycrystalline material constituting the dielectric ceramic composition to suppress variations in retained capacitance due to firing temperature fluctuations and to inhibit the migration of oxygen defects within the grain boundaries and shells, thereby suppressing a decrease in resistivity and improving electrical life.

[0077] The average particle size of the first crystal particles 41 in the dielectric ceramic composition is within a range of 50 nm to 500 nm, and no large particles larger than 3 μm are present in areas where the dielectric is used electrically. For example, the maximum particle size of the first crystal particles in the dielectric ceramic composition is preferably 2 μm or less. Furthermore, given the characteristic of conventional ceramics, where the particle size and composition distribution of the contained crystal particles are controlled within a relatively narrow range, if it can be confirmed that the first crystal particles 41 have a core-shell structure, it can be argued that the presence of multiple first crystal particles 41 with the same structure can positively impact the electrical life of the dielectric ceramic composition.

[0078] The particle size of the first crystal particles 41 can be measured using the following procedure. A dielectric ceramic composition containing first crystal particles 41 is cut or polished to expose the observation surface. This exposure method is not particularly limited; methods such as cutting or polishing the component can be used. To fully observe the internal ceramic structure, it is preferable to use a diamond polishing paste with a fineness of 2 μm or less to achieve a smoothness that can be judged as a mirror surface. Next, after vapor-depositing a conductive material such as platinum or osmium onto the observation surface, the first crystal particles 41 are observed using a scanning electron microscope (SEM) and photographed. Multiple parallel straight lines are drawn in the photograph, and the length of the line segments obtained by cutting each straight line at the periphery of each first crystal particle 41 (the distance between the two points where each straight line intersects the periphery of the first crystal particle 41) is used as the particle size (grain size) of the first crystal particles 41. In this method, the particle size of at least 400 first crystal particles 41 is measured, and the average of the results is taken as the average particle size of the first crystal particles 41. If the outlines of the first crystal grains 41 are difficult to see in the exposed ceramic, the exposed ceramic may be heat treated (thermal etching) for about 5 minutes at a temperature about 50°C lower than the firing temperature before evaporating platinum or osmium. Alternatively, chemical etching may be performed using an acid such as hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, or a mixture thereof at an appropriate concentration, in place of the heat treatment.

[0079] Regarding the core-shell structure of the first crystal particles 41, the added gadolinium, manganese, and titanium react on the surface of the barium titanate crystal particles, forming a shell in the form of a composite perovskite compound believed to be Gd(Ti,Mn)O3, or Gd(Mg,Ti,Mn)O3, (Gd,Ba)(Ti,Mn)O3, or (Gd,Ba)(Mg,Ti,Mn)O3. At this time, because the added titanium participates in the reaction, the solid solution reaction into the barium titanate crystal particles can be relatively suppressed compared to the case where no addition is made. By utilizing this effect, as an example, by applying it to multilayer ceramic capacitors that require high mass production, it is possible to complete firing in a shorter time and suppress the fluctuation in electrostatic capacitance caused by changes in firing temperature, thereby achieving high mass production.

[0080] The presence of the first crystal particles 41 having a core-shell structure in the dielectric ceramic composition can be confirmed by the following procedure.

[0081] First, a sample for observation using a transmission electron microscope (TEM) is cut out from the dielectric ceramic composition to be examined. This cutting can be performed using a focused ion beam (FIB) apparatus or the like.

[0082] Next, the sample cut out for TEM observation is observed using a TEM equipped with an energy dispersive X-ray spectrometer (EDS) or a wavelength dispersive X-ray spectrometer (WDS) to identify the crystal grains to be measured and the peripheral shape of the grains.

[0083] Then, if Figure 3 As shown in the example, among the line segments connecting any two points on the periphery of the crystal particle being measured, the longest line segment is determined, and the length L of this line segment is measured. This length L is then used as the diameter of the crystal particle being measured. Furthermore, the midpoint M of the line segment is determined based on the obtained length of the line segment.

[0084] For any point C on the periphery of a range of lengths that is 10% of the diameter of the crystal grain, or 10L / 100, from the ends of the aforementioned line segment, a composition analysis is performed using EDS or WDS to calculate the elemental abundance ratio of the analyzed element to titanium. In composition analysis, such as EDS measurement, the intensities of titanium K-rays relative to barium K-rays or L-rays, gadolinium L-rays, manganese K-rays, and magnesium K-rays can be simply determined. More specifically, corrections are made to these intensities to account for atomic number effects, absorption effects, and fluorescence excitation effects (ZAF corrections), and the ratios of the respective elemental contents relative to titanium are calculated. These ratios are then used as the ratios of the respective elements in the shell 412 relative to titanium. Furthermore, a similar composition analysis is performed on the midpoint M of the aforementioned line segment, and the ratios are calculated, which are used as the ratios of the respective elements in the core 411 relative to titanium.

[0085] Next, the ratios of the elements relative to titanium in the shell 412 and the core 411 were compared. The ratios of the elements relative to titanium in the shell 412 were higher than those in the core 411 , and thus the first crystal particle 41 to be measured was determined to have a core-shell structure.

[0086] In addition to first crystal particles 41 , the dielectric ceramic composition also contains at least one type of second crystal particles 42 formed of a barium titanate-based composite oxide having a barium to titanium element ratio of 0.70 or less as second crystal particles 42 other than first crystal particles 41 .

[0087] In the second crystal particles 42, the element ratio of barium to titanium is preferably 0.16 or greater. Furthermore, the second crystal particles 42 may contain manganese. The element ratio of manganese to titanium in the second crystal particles may be 0.02 or greater and 0.10 or less, or 0.02 or greater and 0.05 or less.

[0088] Examples of the second crystal particles 42 include BaTi2O5, BaTi4O9, and BaTi5O 11 、BaTi6O 13 、Ba4Ti 11 O 26 、Ba4Ti 12 O 27 、Ba4Ti 13 O 30 、Ba6Ti 17 O 40 wait.

[0089] As can be seen from its compositional formula, the second crystal particles 42 are barium titanate composite oxides containing a smaller amount of barium than barium titanate. As described above, in the dielectric ceramic composition of this embodiment, the second crystal particles 42 form shells 412 in the form of a composite perovskite compound, such as Gd(Ti,Mn)O3, Gd(Mg,Ti,Mn)O3, (Gd,Ba)(Ti,Mn)O3, or (Gd,Ba)(Mg,Ti,Mn)O3. Therefore, when an additive primarily composed of titanium is used, these crystal particles become by-products. By intentionally precipitating the second crystal particles 42, first crystal particles 41 can be obtained. This, for example, can suppress the magnitude of capacitance fluctuations caused by firing temperature changes in multilayer ceramic capacitors, which require high mass productivity, thereby achieving high mass productivity. Furthermore, the dielectric ceramic composition according to this embodiment, which has second crystal grains 42, requires firing at a relatively high temperature to form the shell portion 412 in the form of the composite perovskite compound described above. Firing at a maximum heating rate of 10°C / min (600°C / h), as disclosed in Patent Documents 1 and 2, has been shown to produce a large number of second crystal grains 42, resulting in large grains exceeding 10 μm in diameter. To mitigate this, the dielectric ceramic composition according to this embodiment should preferably be fired at a rapid heating rate of 3000°C / h to 10000°C / h, minimizing the amount of heat applied during firing and suppressing grain growth.

[0090] As a more preferred example of the second crystal particles 42, Ba4Ti 11 O 26 The morphology is monoclinic and the space group is represented by C2 / m, and the lattice constant is Barium titanate composite oxide with β = 98.6°. This is because the ratio of barium to titanium in this barium titanate composite oxide is relatively close to 1, making it easy to intentionally precipitate even without the use of additives containing a large amount of titanium as the main component. This barium titanate composite oxide is described, for example, in the non-patent document Acta Cryst. (1979). B35, 1590-1593.

[0091] As a further preferred example of the second crystal particles 42, it is desirable that manganese is solid-dissolved in Ba4Ti 11 O 26 , occupying its defect sites or replacing part of titanium. 11 O 26The formation of some titanium sites creates a defective crystal structure. Therefore, at these defective sites, titanium easily converts from a tetravalent cation to a trivalent cation, resulting in a decrease in resistivity. To compensate for this, the addition of manganese in a solid solution is effective.

[0092] Among them, it can be confirmed that the dielectric ceramic composition contains the second crystal grains 42 by the following procedure.

[0093] First, the diffraction pattern of the surface of the dielectric ceramic composition to be confirmed, or the powder obtained by crushing the dielectric ceramic composition, is measured by an X-ray diffractometer (XRD) using Cu-Kα rays. The crushing method used to obtain the powder is not particularly limited, and a hand grinder (mortar, pestle) or the like can be used. In addition, when measuring the diffraction pattern of the ceramic constituting the multilayer ceramic capacitor, the electrodes or coating layers formed on the surface of the element, and the parts other than the dielectric layer of the multilayer ceramic capacitor are removed to expose the surface of the dielectric ceramic composition. The exposure method is not particularly limited, and methods such as cutting or grinding the element can be used. In addition, when measuring the diffraction pattern of the powder of the dielectric ceramic composition constituting the multilayer ceramic capacitor, it is more appropriate to remove the parts other than the electrodes or coating layers formed on the element, and the dielectric layer of the multilayer ceramic capacitor, and then crush it.

[0094] Next, in the resulting diffraction pattern, the percentage of the strongest diffraction line intensity originating from other structures relative to the strongest diffraction line intensity originating from the perovskite structure is calculated. If this ratio is 10% or less, the dielectric ceramic composition being examined is determined to be composed of first crystal particles 41 having a perovskite structure. Furthermore, when the surface of the dielectric ceramic composition of a multilayer ceramic capacitor is exposed using the aforementioned method, or when XRD analysis is performed on the pulverized powder, peaks from materials constituting the electrodes or coating layers may also be detected. Therefore, these peaks are excluded before calculating the above-described ratio of diffraction line intensities.

[0095] Next, focus on the peaks other than the diffraction line intensity from the perovskite structure to identify the crystalline phase. For the identification of the crystalline phase, it is recommended to search the PDF (Powder Diffraction File) issued by ICDD (International Centre for Diffraction Data; Pennsylvania, USA) to check whether the second crystalline particles 42 are present. In the case of Ba4Ti, which is a preferred example, the second crystalline particles 42 are present. 11 O 26 By referring to PDF-01-083-1459 for identification, its generation can be evaluated.

[0096] Next, it was determined by the following method that the second crystal particles 42 were composed of a barium titanate-based composite oxide having an element ratio of barium to titanium of 0.70 or less.

[0097] First, the surface of the dielectric ceramic composition is exposed. The method for this exposure is not particularly limited; cutting or polishing the component can be employed. To fully observe the internal ceramic structure, it is preferable to use a diamond polishing paste with a thickness of 2 μm or less, which achieves a smoothness comparable to a mirror surface.

[0098] Next, the composition of the second crystal grains 42 is identified using an energy dispersive X-ray spectrometer (EDS) or a wavelength dispersive X-ray spectrometer (WDS) equipped with a scanning electron microscope (SEM) or a transmission electron microscope (TEM), an electron probe microanalyzer (EPMA), and a laser irradiation inductively coupled plasma mass spectrometer (LA-ICP-MS).

[0099] For example, in EDS measurement, the content of titanium is determined simply by the intensity of K-rays from titanium relative to K-rays or L-rays from barium and K-rays from manganese. More specifically, these intensities are corrected to take into account the effects of atomic number, absorption, and fluorescence excitation (ZAF correction), and the ratio of each element relative to the content of titanium is calculated as the ratio of each element.

[0100] When performing EDS measurements, particularly those using barium Lα radiation and titanium Kα radiation, their energy peaks are close together, making it difficult to adequately compare elemental contents. In such cases, it is desirable to obtain barium Lβ2 radiation and LIIIab radiation at sufficient intensity without peak overlap. Specifically, the peak intensity is preferably 10,000 counts or higher. This allows the intensity of the characteristic X-rays generated by barium to be determined, allowing elemental content to be calculated. Therefore, even if barium Lα radiation and titanium Kα radiation overlap, the intensity of titanium Kα radiation can be determined, enabling highly accurate evaluation of elemental content.

[0101] When the barium-to-titanium ratio obtained by the above method is 0.70 or less, the crystal particle is determined to be a second crystal particle 42. Specifically, the presence of a lower barium-to-titanium ratio than that of the surrounding first crystal particles 41, formed of barium titanate, allows the particle to be identified as any of the aforementioned barium titanate composite oxides. In this case, when observing using a SEM, observation using a backscattered electron image (BSE image) reveals that the second crystal particles 42 have a relatively low brightness relative to the first crystal particles 41, resulting in them appearing darker. Furthermore, as a more preferred determination, it is desirable to identify the second crystal particles 42 by evaluating their diffraction patterns using XRD.

[0102] Next, in more detail, the portion identified as the second crystal grain 42 was cut out as a sample for observation with a transmission electron microscope (TEM), and the diffraction image obtained using the restricted field diffraction method was compared with data obtained from known literature to confirm whether it could be identified as BaTi2O5, BaTi4O9, BaTi5O 11 、BaTi6O 13 、Ba4Ti 11 O 26 、Ba4Ti 12 O 27 、Ba4Ti 13 O 30 or Ba6Ti 17 O 40 The cutting can be performed using a FIB device or the like.

[0103] The solid solution of manganese in the second crystal particles 42 can be confirmed by measuring the intensity of titanium K-ray relative to Mn K-ray using EDS, WDS, or EPMA. More specifically, ZAF correction is performed based on these intensities to calculate the ratio w of the element content of manganese to the element content of titanium. In this case, it is desirable to be in the range of 0.02≤w≤0.10, and more preferably in the range of 0.02≤w≤0.05. In this case, as an example, in Ba4Ti 11 O 26 The defective positions of the Ti sites are in a state where manganese is solid-solved, and a decrease in the resistivity of the dielectric ceramic composition can be suppressed.

[0104] The dielectric ceramic composition may also contain third crystal particles 43 having a different composition or crystal structure from the first crystal particles 41 and the second crystal particles 42. Furthermore, the dielectric ceramic composition may also contain crystal particles containing silicon or glass particles. This allows the dielectric ceramic composition to be fired at 1300°C or lower, achieving sufficient densification.

[0105] Examples of the third crystal particles 43 include crystal particles of silicate (SiO 2 ), enstatite (MgSiO 3 ), barium magnesium silicate (BaMgSiO 4 ), fresnoite (Ba 2 TiSi 2 O 8 ), and glass particles.

[0106] In addition, examples of the third crystal particles 43 include compounds derived from additives or by-products of electrodes, such as magnesia titanate (MgTiO 3 ), manganese nickel oxide ((Mn,Ni)O), and ruthenium titanate (MnTiO 3 ).

[0107] (Second embodiment)

[0108] In the second embodiment, a multilayer ceramic capacitor 100 using the dielectric ceramic composition according to the first embodiment will be described.

[0109] Figure 4 FIG. 1 is a partial cross-sectional perspective view of the multilayer ceramic capacitor 100 . Figure 5 yes Figure 4 A-A line cross-section diagram. Figure 6 yes Figure 4 BB line cross section diagram. Figures 4-6 As shown, the multilayer ceramic capacitor 100 includes a generally rectangular parallelepiped multilayer chip 10 and external electrodes 20a and 20b provided on two opposing end surfaces of the multilayer chip 10. Of the four surfaces of the multilayer chip 10 other than the two end surfaces, two surfaces other than the top and bottom surfaces in the stacking direction are referred to as side surfaces. The external electrodes 20a and 20b extend to the top, bottom, and side surfaces of the multilayer chip 10 in the stacking direction. However, the external electrodes 20a and 20b are spaced apart from each other.

[0110] The laminate 10 has a structure in which dielectric layers 11 containing a dielectric ceramic composition and internal electrode layers 12 containing a base metal material are alternately stacked. The end edges of each internal electrode layer 12 are alternately exposed at the end surface of the laminate 10 provided with the external electrode 20a and the end surface provided with the external electrode 20b. As a result, each internal electrode layer 12 is alternately electrically connected to the external electrode 20a and the external electrode 20b. As a result, the laminated ceramic capacitor 100 has a structure in which a plurality of dielectric layers 11 are stacked with internal electrode layers 12 interposed therebetween. In addition, in the laminate of the dielectric layers 11 and the internal electrode layers 12, the internal electrode layers 12 are arranged as the outermost layers in the stacking direction, and the upper and lower surfaces of this laminate are covered with a cover layer 13. The cover layer 13 is mainly composed of a ceramic material. For example, the material of the cover layer 13 is the same as the main component of the ceramic material of the dielectric layer 11.

[0111] The dimensions of the multilayer ceramic capacitor 100 are, for example, 0.25 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.

[0112] The internal electrode layer 12 is mainly composed of base metals such as Ni (nickel), Cu (copper), and Sn (tin). Precious metals such as Pt (platinum), Pd (palladium), Ag (silver), and Au (gold), or alloys containing these metals, may also be used as the internal electrode layer 12.

[0113] like Figure 4 In the illustrated example, the region where the internal electrode layer 12 connected to the external electrode 20a and the internal electrode layer 12 connected to the external electrode 20b face each other is the region where capacitance is generated in the multilayer ceramic capacitor 100. Therefore, this region where capacitance is generated is referred to as the capacitance region 14. In other words, the capacitance region 14 is the region where adjacent internal electrode layers 12 connected to different external electrodes face each other.

[0114] The region where internal electrode layers 12 connected to external electrode 20a face each other without interposing internal electrode layers 12 connected to external electrode 20b is referred to as end edge 15. Furthermore, the region where internal electrode layers 12 connected to external electrode 20b face each other without interposing internal electrode layers 12 connected to external electrode 20a is also referred to as end edge 15. In other words, end edge 15 is a region where internal electrode layers 12 connected to the same external electrode face each other without interposing internal electrode layers 12 connected to different external electrodes. End edge 15 is a region where no capacitance is generated.

[0115] like Figure 6 In the illustrated example, in the laminate 10, the region extending from both side surfaces of the laminate 10 to the internal electrode layers 12 is referred to as the side edge 16. Specifically, the side edge 16 is a region extending to the ends of both side surfaces of the plurality of internal electrode layers 12 stacked in the laminate structure described above. The side edge 16 is also an area that does not generate capacitance.

[0116] In the multilayer ceramic capacitor 100 according to this embodiment, at least a portion of the dielectric layer 11 in the capacitor region 14 contains Figure 2 The first crystal particles 41 shown in the example are included, and the second crystal particles 42 are included. This can suppress the rate of change in capacitance due to changes in firing temperature, and can achieve high mass productivity.

[0117] Next, a method for manufacturing the multilayer ceramic capacitor 100 will be described. Figure 7 1 is a diagram illustrating the flow of a method for manufacturing the multilayer ceramic capacitor 100 .

[0118] (Raw material powder production process)

[0119] First, a dielectric ceramic composition for forming dielectric layer 11 is prepared. The A-site element and B-site element contained in dielectric layer 11 are generally contained in dielectric layer 11 in the form of a sintered body of ABO3 particles. For example, barium titanate is a compound having a perovskite structure and a tetragonal system at around room temperature, exhibiting a high relative dielectric constant. This barium titanate can generally be synthesized by reacting a titanium raw material such as titanium dioxide with a barium raw material such as barium carbonate. Various methods are currently known for synthesizing barium titanate, the main component of dielectric layer 11, such as a solid phase method, a sol-gel method, and a hydrothermal method. In this embodiment, any of these methods can be used.

[0120] Predetermined additives are added to the barium titanate powder obtained by the above method. For example, additives within the ranges shown in the examples of the dielectric ceramic composition according to the first embodiment can be used. Oxides or glasses containing Zr (zirconium), V (vanadium), Cr (chromium), Co (cobalt), Ni (nickel), Li (lithium), B (boron), Na (sodium), or K (potassium) can be used as needed. Furthermore, as needed, oxides of Sc (scandium), Y (yttrium), La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Y (ytterbium), and Lu (lutetium) can be added as rare earth elements other than Gd.

[0121] For example, a compound containing an additive compound is wet-mixed with barium titanate powder, followed by drying and pulverization to produce a ceramic material comprising the barium titanate powder and the additive compound. For example, the ceramic material obtained as described above can be subjected to pulverization to adjust the particle size, or can be combined with classification to adjust the particle size, as needed. Specifically, the ceramic material can be stirred for 10 to 100 hours with beads having a diameter of 0.1 to 3 mm, such as those made of yttrium-stabilized zirconia, alumina, or silicon nitride. The above process can produce a dielectric ceramic composition.

[0122] (Coating process)

[0123] Next, a binder such as polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer are added to the resulting dielectric ceramic composition and wet-mixed. The resulting slurry is applied to a substrate using, for example, a die coating method or a doctor blade method, and then dried. The substrate is, for example, a polyethylene terephthalate (PET) film. Figures illustrating the coating process are omitted.

[0124] (Internal Electrode Forming Process)

[0125] Then, if Figure 8 As shown in (a), a metal conductive paste containing an organic binder for forming internal electrodes is printed on the surface of a ceramic green sheet 51 by screen printing, gravure printing, or the like, thereby configuring an internal electrode pattern 52 that is alternately extended to a pair of external electrodes of different polarities. Ceramic particles are added to the metal conductive paste as a co-material. The main component of the ceramic particles is not particularly limited, but is preferably the same as the main component ceramic of the dielectric layer 11. For example, barium titanate with an average particle size of 50 nm or less can be uniformly dispersed.

[0126] Next, a binder such as ethyl cellulose and an organic solvent such as terpineol are added to the dielectric ceramic composition obtained in the raw material powder production step, and the mixture is kneaded using a roll mill to obtain a dielectric pattern paste for the reverse pattern layer. Figure 8 As shown in (a), a dielectric pattern paste is printed on a ceramic green sheet 51 in the peripheral area where the internal electrode pattern 52 is not printed, thereby forming a dielectric pattern 53 to fill the height difference with the internal electrode pattern 52. The ceramic green sheet 51 printed with the internal electrode pattern 52 and the dielectric pattern 53 is referred to as a stacked unit.

[0127] Afterwards, if Figure 8 As shown in the example of (b), the stacked units are stacked so that the internal electrode layers 12 and the dielectric layers 11 are interlaced, and the edges of the internal electrode layers 12 are alternately exposed at both end surfaces in the longitudinal direction of the dielectric layer 11 and are alternately led to a pair of external electrodes 20a and 20b of different polarities. For example, the number of stacked internal electrode patterns 52 is set to 100 to 1000.

[0128] (Crimp process)

[0129] like Figure 9 As shown in the example, the cover sheets 54 are laminated and hot-pressed in a predetermined number (e.g., 2 to 10 layers) on the upper and lower sides of the laminated body formed by laminating the laminated units. As an example, the above-mentioned dielectric ceramic composition can be used as the ceramic material of the cover sheet 54. Thereafter, it is cut into a predetermined sheet size (e.g., 1.0 mm × 0.5 mm). In addition, the side edge portion can also be pasted or coated on the side of the above-mentioned laminated portion. Specifically, Figure 10 As shown, the laminated portion is obtained by alternately laminating ceramic green sheets 51 and internal electrode patterns 52 having the same width as the ceramic green sheets 51. Next, a sheet formed of a dielectric pattern paste may be attached to the side surfaces of the laminated portion as side margins 55.

[0130] (Firing process)

[0131] The ceramic laminate obtained as described above is subjected to a binder removal treatment in an N2 atmosphere, an air atmosphere, or the like, and then a metal paste for forming a base layer of the external electrodes 20a and 20b is applied by a dipping method. -12 ~10 -9 The laminated ceramic capacitor 100 is then fired in a reducing atmosphere at 1100-1300°C for 10 minutes to 2 hours. Furthermore, the firing process involves rapid temperature increase. The firing rate is, for example, 6000°C / h. This prevents the second crystal particles 42 from forming large particles, shortens the actual firing time, and achieves higher mass productivity.

[0132] (Reoxidation treatment process)

[0133] Thereafter, a reoxidation treatment may be performed in an N2 gas atmosphere at 600°C to 1000°C.

[0134] (Plating treatment process)

[0135] Thereafter, the base layers of the external electrodes 20a and 20b are plated with a metal such as Cu, Ni, or Sn. The multilayer ceramic capacitor 100 is completed through the above steps.

[0136] By using the manufacturing method according to this embodiment, it is possible to form a dielectric layer 11 in at least a portion of the capacitor region 14. Figure 2 The first crystal particles 41 exemplified in FIG can contain the second crystal particles 42 . Therefore, in a multilayer ceramic capacitor requiring high productivity, the rate of change in capacitance due to a change in firing temperature can be suppressed, thereby achieving high productivity.

[0137] The firing temperature dependence (Δε / °C) of the relative dielectric constant of the multilayer ceramic capacitor 100 due to the firing temperature change was determined using the following method. First, the capacitance Cp (nF) and the DC current I (nA) of the multilayer ceramic capacitor 100 after the firing process, the reoxidation process, and the plating process were measured. Next, the capacitance Cp (nF) and the DC current I (nA) of the multilayer ceramic capacitor 100 were measured. Figure 5 and Figure 6The capacitor region 14 is exposed by cutting or polishing the AA and BB cross sections shown in the example, and finally the effective area of ​​the internal electrode layer is calculated using a diamond polishing paste of less than 2 μm to obtain a smoothness that can be judged as a mirror surface.

[0138] according to Figure 5 The length L and the number of stacking layers N of the internal electrode layer 12 in the capacitor region 14, and Figure 6 The effective area S is calculated from the width W of the internal electrode layer 12 of the capacitor region 14 in FIG. 1 , as S=L×W×(N−1).

[0139] In addition, at this time, the thickness of each dielectric layer 11 is also measured to calculate the average thickness t. At this time, the relative dielectric constant ε can be calculated according to ε = (Cp × t / S) / ε0, and according to ε0 = 8.8542 × 10 -12 F / m is used to calculate the dielectric constant of vacuum.

[0140] When the DC voltage during measurement is V (V), the DC resistivity ρ (Ω·cm) can be calculated according to ρ=(V / I)×(S / t).

[0141] The electrostatic capacitance Cp is typically preferably measured using an LCR meter. The measurement frequency and voltage must be determined. The voltage is preferably determined by setting a measurement electric field that is proportional to the thickness of the dielectric layer 11. In this embodiment, the electrostatic capacitance Cp can be measured at room temperature of 25°C, with a measurement frequency of 1 kHz and a measurement electric field of 0.5 Vrms / μm (i.e., 1 Vrms when the thickness of the dielectric layer 11 is 2 μm).

[0142] In addition, regarding the DC current I, it is usually preferred to use an insulation resistance meter for measurement. During the measurement, it is necessary to determine the measurement voltage, which is preferably determined by setting a measurement electric field related to the thickness of the dielectric layer 11. In this embodiment, the multilayer ceramic capacitor 100 can be kept in a constant temperature bath at 150°C for 30 minutes, and a ceramic insulator or the like is used to ensure insulation from the surroundings. A measurement electric field of 30V / μm is applied through wires connected from the constant temperature bath to the external electrodes 20a and 20b (for example, when the thickness of the dielectric layer 11 is 2μm, 60V is applied for 30 seconds) to measure the DC current I and calculate the DC resistivity ρ. Among them, regarding the measurement, unless otherwise specified, it is measured in accordance with Japanese Industrial Standard C5101-22:2021 Fixed capacitors for electronic equipment - Part 22: Sub-specification - Class 2 fixed multilayer ceramic capacitors for surface mounting.

[0143] Next, the DC resistivity, ρ, of the multilayer ceramic capacitors obtained at each firing temperature was measured. The firing temperature that maintained the highest resistivity was determined as the optimal firing temperature. Generally, too low a firing temperature results in low density and low resistivity, while too high a firing temperature enlarges the ceramic grains, reducing the number of grain boundaries and thus decreasing the resistivity.

[0144] Next, the relative dielectric constant ε of the multilayer ceramic capacitor obtained at the firing temperature that maintains the highest resistivity, and the relative dielectric constants of the multilayer ceramic capacitors fired at a firing temperature of -20°C, which maintains the highest resistivity, and at a firing temperature of +20°C, which maintains the highest resistivity, were used. Based on these firing temperatures and relative dielectric constants, the slope of the straight line was calculated using the least squares method to determine the firing temperature dependence of the relative dielectric constant (Δε / °C), and this value was used as an indicator of high mass productivity.

[0145] The DC resistivity measured at 150°C is expected to be 2.0×10 8 Ω·cm or more. By reaching 2.0×10 8 The multilayer ceramic capacitor 100 using the dielectric ceramic composition of the present embodiment can have a sufficient resistance of Ω·cm or more.

[0146] The DC resistivity measured at 150°C is more preferably 1.0×10 10 Ω·cm or more. The reason is that by reaching 1.0×10 10 Ω·cm or more, the multilayer ceramic capacitor 100 using the dielectric ceramic composition of this embodiment not only has sufficient resistance but can also be designed to be thinner, making it easier to increase the number of stacked internal electrodes.

[0147] Δε / °C is preferably 12 or less. When 12 or less, the multilayer ceramic capacitor 100 using the dielectric ceramic composition of this embodiment can be fired in a shorter time, and changes in capacitance due to changes in firing temperature can be suppressed, thereby achieving high mass productivity.

[0148] Furthermore, Δε / °C is preferably 6 or less. When 6 or less, the multilayer ceramic capacitor 100 using the dielectric ceramic composition of this embodiment can be fired in a shorter time, and changes in capacitance due to changes in firing temperature can be suppressed, thereby achieving high mass productivity.

[0149] The relative dielectric constant ε is preferably 2500 or more. Even if the DC resistivity measured at 150°C is 2.0×10 8If the dielectric constant has a firing temperature dependence Δε / °C of 12 or less, and if ε is small, the capacitance Cp is insufficient, resulting in characteristics that are unsuitable for the use of the multilayer ceramic capacitor 100 using the dielectric ceramic composition.

[0150] Furthermore, in the above-described embodiments, a multilayer ceramic capacitor is described as an example of a multilayer ceramic electronic component, but the present invention is not limited thereto. For example, other multilayer ceramic electronic components such as a varistor or a thermistor may also be used.

[0151] Example

[0152] (Example 1)

[0153] Barium titanate powder with an average particle size of 150 nm was prepared. To 100 mol of the barium titanate powder, 0.75 mol of Gd2O3, 0.5 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to obtain a dielectric ceramic composition. The Ba / Ti element ratio was 0.995.

[0154] A dielectric ceramic composition is mixed with ethanol, toluene, and PVB (polyvinyl butyral) resin to produce a dielectric slurry. This slurry is molded into ceramic green sheets using a die coater. After drying the ceramic green sheets, nickel paste is printed to form an internal electrode pattern. The resulting laminated units are stacked, and thicker ceramic green sheets without internal electrode patterns are stacked on top and bottom to form layers, which are then pressed together and cut into small pieces. Afterwards, Ni paste is impregnated on both end faces as a conductive paste for external electrodes, and degreased in nitrogen. The degreased small pieces are fired in a reducing atmosphere with an oxygen partial pressure controlled to prevent nickel oxidation, and sintered to produce a laminated ceramic capacitor. The firing temperature is 1220°C.

[0155] The resulting multilayer ceramic capacitor had a 1005 shape (1.0 mm × 1.0 mm × 0.5 mm). Reoxidation treatment was then performed at 950°C. Plating was then performed to form Cu, Ni, and Sn plating layers on the surface of the base layer, resulting in a multilayer ceramic capacitor. The average thickness of the dielectric layer 11 was 2.0 μm.

[0156] (Example 2)

[0157] In Example 2, 0.75 mol of Gd2O3, 1.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.990, and the firing temperature was set to 1230°C. Other conditions were the same as in Example 1.

[0158] (Example 3)

[0159] In Example 3, 0.75 mol of Gd2O3, 2.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.980. The firing temperature was set to 1240°C. Other conditions were the same as in Example 1.

[0160] (Example 4)

[0161] In Example 4, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0162] (Example 5)

[0163] In Example 5, 0.75 mol of Gd2O3, 8.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.926. The firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0164] (Comparative Example 1)

[0165] In Comparative Example 1, a dielectric ceramic composition was obtained by adding 1.5 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 to 100 mol of barium titanate powder without adding Gd2O3. The Ba / Ti element ratio was set to 0.985, and the firing temperature was set to 1220°C. Other conditions were the same as in Example 1.

[0166] (Comparative Example 2)

[0167] In Comparative Example 2, 0.75 mol of Gd2O3, 0.2 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.998, and the firing temperature was set to 1210°C. Other conditions were the same as in Example 1.

[0168] For each of the multilayer ceramic capacitors of Examples 1 to 5 and Comparative Examples 1 and 2, the capacitance Cp at room temperature (25°C) was measured using an LCR meter at 1 kHz and 1 Vrms, and the DC current I at 150°C was measured using an insulation resistance meter when 60 V was applied for 30 seconds. Figure 4 The A-A cross section and the B-B cross section are exposed, and the effective area S of the internal electrode layer and the average thickness t of the dielectric layer are calculated. Based on the effective area S and the average thickness t, the relative dielectric constant ε and the resistivity ρ are calculated. Then, the resistivity ρ of each multilayer ceramic capacitor of Examples 1 to 5 and Comparative Examples 1 and 2 are compared, and the relative dielectric constant of the multilayer ceramic capacitor obtained at the firing temperature with the highest resistivity and the relative dielectric constant of the multilayer ceramic capacitor fired at the firing temperature of -20°C and the firing temperature of +20°C are referred to. Based on these firing temperatures and relative dielectric constants, the slope of the straight line is calculated using the least squares method, which is defined as the firing temperature dependence of the relative dielectric constant (Δε / °C).

[0169] Furthermore, an osmium conductive material was vapor-deposited on the exposed dielectric layer, and the crystal particles present in the dielectric layer were photographed using a SEM. The average particle size of the crystal particles constituting the dielectric layer was then calculated.

[0170] Furthermore, when observing the multilayer ceramic capacitor under SEM, the presence of second crystal particles 42 in the BSE image is confirmed by the difference in brightness. For areas with relatively low brightness and appearing dark, EDS composition evaluation is used to confirm whether they are crystal particles formed from a barium titanate composite oxide with a barium to titanium ratio v of 0.70 or less. Furthermore, the manganese to titanium ratio in these areas is also checked to confirm whether the Mn / Ti ratio w satisfies 0.02 ≤ w ≤ 0.10.

[0171] Furthermore, for each multilayer ceramic capacitor, in order to confirm the composition of the shell and core portions of the crystal grains in the dielectric layer, samples for EDS observation using TEM were cut out using FIB, and the presence of a core-shell structure was confirmed using a composition evaluation method using EDS.

[0172] In addition, for each laminated ceramic capacitor, after cutting off the cover layer, end edges, side edges, and external electrodes outside the capacitor area by grinding or cutting, the dielectric layer constituting the capacitor area is crushed, and the resulting powder is measured by using an X-ray diffraction device (XRD) using Cu-Kα rays to determine the presence of diffraction line patterns that can be identified as Ba4Ti 11 O 26 The second crystal particles 42 are formed.

[0173] Table 1 summarizes the amounts of additives added in Comparative Examples 1 and 2 and Examples 1 to 5, as well as their firing temperatures, average particle sizes, ε, Δε / °C, and resistivity at 150°C.

[0174] [Table 1]

[0175]

[0176] Comparative Example 1 is a comparative example in which gadolinium, a rare earth element, is not included. Comparative Example 2 is a comparative example in which the amount of added TiO2 is small, reaching the lower limit. In Comparative Example 1, since gadolinium, a rare earth element, is not included, the particle size during firing cannot be controlled, and a large amount of particles grow to 2400 nm, resulting in a low resistance state. In Comparative Example 2, since gadolinium, a rare earth element, is included, the average particle size is 520 nm, and the resistivity at 150°C reaches 2.6×10 10 Ω·cm, and sufficient resistivity can be maintained. However, due to insufficient TiO2 addition, the value of Δε / °C becomes 12.5, and the preferred value of 12 or less cannot be obtained.

[0177] In Examples 1 to 5, the amount of TiO2 added is 0.5 mol to 8.0 mol relative to 100 mol of BaTiO3, and the Ba / Ti element ratio x in the dielectric layer is in the range of 0.926≤x≤0.995. Within this range, the value of Δε / °C is 12 or less. In particular, when the amount of TiO2 added is 1.0 mol or more, Δε / °C is 3 or less. For example, in order to improve production efficiency, even when a larger firing furnace than the existing firing furnace is used, the relative dielectric constant obtained, that is, the value of the electrostatic capacitance Cp of the stacked ceramic capacitor does not have a large distribution relative to the temperature distribution in the furnace. Therefore, in a short firing time using high-speed temperature rise, larger mass production can be achieved. In addition, the average particle size is also less than 500 nm, and the resistivity is also 2.0×10 8 Ω·cm or more, so an ideal electrical life can be obtained.

[0178] In order to examine the mechanism of the dielectric layer in detail, the laminated ceramic capacitors obtained using Comparative Examples 1 and 2 and Examples 1 to 5 were analyzed by TEM-EDS, SEM-EDS, and XRD to determine whether a core-shell structure and the presence of Ba4Ti 11 O 26 , and whether the element ratio v of Ba to Ti in the second crystal particles 42 is in the range of 0.16≤v≤0.70, and whether the element ratio w of Mn to Ti is in the range of 0.02≤w≤0.10. The results are summarized in Table 2.

[0179] [Table 2]

[0180]

[0181] In Comparative Example 1, since gadolinium as a rare earth element is not contained, a core-shell structure is not obtained. The Mn / Ti ratio of the shell in Comparative Example 1 is Figure 3 The Mn / Ti ratio of the core is measured at point C in Figure 3 The Mn / Ti ratio is measured at the midpoint M in the comparative example 2. In the comparative example 2, the addition amount of TiO2 is insufficient, so the Ba4Ti 11 O 26 Furthermore, in SEM-EDS, the presence of the second crystal particles 42 , which have relatively low brightness and appear dark, cannot be confirmed for the main crystal particles formed of barium titanate.

[0182] On the other hand, in Examples 1 to 5, it was determined that a core-shell structure existed, and Ba4Ti 11 O 26 , and the element ratio v of Ba to Ti and the element ratio w of Mn to Ti in the second crystal grains 42 are in the ranges of 0.16≤v≤0.70 and 0.02≤w≤0.10, respectively, indicating the presence of the second crystal grains 42. In addition, as shown in Table 1, the value of Δε / °C is 12 or less, and the resistivity is also 2.0×10 8 Ω·cm or more, and an average particle size of 500 nm or less, and a relative dielectric constant of ε>2500 or more.

[0183] To verify whether similar effects are achieved when controlling the type of rare earth element, the amount of rare earth element, the amount of manganese, the amount of silicon, and the amount of magnesium in the dielectric ceramic composition, a multilayer ceramic capacitor comprising the dielectric ceramic composition was fabricated as an example within the scope of the present invention using the same operating procedures as those in Comparative Examples 1 and 2 and Examples 1 to 5.

[0184] [Verification of the Effect of Changing the Type of Rare Earth Elements]

[0185] (Example 6)

[0186] In Example 6, 0.75 mol of Eu2O3 (europium oxide), 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1280°C. Other conditions were the same as in Example 1.

[0187] (Example 7)

[0188] In Example 7, 0.75 mol of Tb2O3 (terbium oxide), 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0189] (Example 8)

[0190] In Example 8, 0.75 mol of Dy2O3 (dysprosium oxide), 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0191] (Example 9)

[0192] In Example 9, 0.75 mol of Y2O3 (yttrium oxide), 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0193] (Example 10)

[0194] In Example 10, 0.75 mol of Ho₂O₃ (holmium oxide), 4.0 mol of TiO₂, 1.5 mol of MnCO₃, and 1.0 mol of SiO₂ were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1250°C. Other conditions were the same as in Example 1.

[0195] (Example 11)

[0196] In Example 11, 0.75 mol of Er₂O₃ (erbium oxide), 4.0 mol of TiO₂, 1.5 mol of MnCO₃, and 1.0 mol of SiO₂ were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1250°C. Other conditions were the same as in Example 1.

[0197] (Example 12)

[0198] In Example 12, 0.75 mol of Yb2O3 (ytterbium oxide), 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1250°C. Other conditions were the same as in Example 1.

[0199] (Example 13)

[0200] In Example 13, 0.375 mol of Gd2O3, 0.375 mol of Dy2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0201] (Example 14)

[0202] In Example 14, 0.375 mol of Eu2O3, 0.375 mol of Ho2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0203] (Example 15)

[0204] In Example 15, 0.25 mol of Gd2O3, 0.25 mol of Tb2O3, 0.25 mol of Y2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1250°C. Other conditions were the same as in Example 1.

[0205] Examples 6 to 12 are examples of dielectric ceramic compositions in which the rare earth element is changed to europium, terbium, dysprosium, holmium, erbium, or ytterbium, and Examples 13 to 15 are examples of dielectric ceramic compositions in which two or more elements are added from the above rare earth elements.

[0206] In Examples 6 to 15, the value of Δε / °C is 2 or less, indicating that the relative dielectric constant is sufficiently stable with respect to the firing temperature. In addition, the average particle size is also 500 nm or less, and the resistivity at 150°C is also 2.0×108 Therefore, even in a short firing time using a high-speed temperature increase, mass production can be achieved and sufficient reliability can be obtained.

[0207] [Verification of the Effect of MnCO3 Addition Amount]

[0208] (Example 16)

[0209] In Example 16, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 0.2 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1280°C. Other conditions were the same as in Example 1.

[0210] (Example 17)

[0211] In Example 17, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.0 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1280°C. Other conditions were the same as in Example 1.

[0212] (Example 18)

[0213] In Example 18, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 2.0 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1230°C. Other conditions were the same as in Example 1.

[0214] (Example 19)

[0215] In Example 19, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 5.0 mol of MnCO3, and 1.0 mol of SiO2 were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1210°C. Other conditions were the same as in Example 1.

[0216] Examples 16 to 19 are examples of dielectric ceramic compositions in which the amount of MnCO3 added was varied within a range of 0.2 mol to 5.0 mol per 100 mol of BaTiO3. In Examples 16 to 19, the Δε / °C value was 12 or less. In particular, when the amount of MnCO3 added was within a range of 1.0 mol to 5.0 mol, the Δε / °C value was 4 or less. Furthermore, the average particle size was 500 nm or less, and the resistivity was 2.0 × 10 8 Ω·cm or more. Therefore, even when using a larger firing furnace than conventional ones, for example to improve productivity, the resulting relative dielectric constant, or the capacitance Cp value of the multilayer ceramic capacitor, does not exhibit large variations relative to the temperature distribution within the furnace. Consequently, even with short firing times utilizing rapid temperature increases, mass production can be achieved while ensuring sufficient reliability.

[0217] [Verification of the Effect of the Addition Amount of MgO]

[0218] (Example 20)

[0219] In Example 20, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.05 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0220] (Example 21)

[0221] In Example 21, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.2 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1290°C. Other conditions were the same as in Example 1.

[0222] (Example 22)

[0223] In Example 22, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0224] (Example 23)

[0225] In Example 23, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 1.0 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0226] (Example 24)

[0227] In Example 24, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 2.0 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1240°C. Other conditions were the same as in Example 1.

[0228] (Example 25)

[0229] In Example 25, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 5.0 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1230°C. Other conditions were the same as in Example 1.

[0230] Examples 20 to 25 are examples of dielectric ceramic compositions in which the amount of MgO added was varied within a range of 0.05 mol to 5.0 mol relative to 100 mol of BaTiO 3 .

[0231] In Examples 20 to 25, the value of Δε / °C is 2 or less, indicating that the relative dielectric constant is sufficiently stable with respect to the firing temperature. In addition, the average particle size is 500 nm or less, and the resistivity is 2.0×10 8 Ω·cm or more. Therefore, even when using a larger firing furnace than conventional ones, for example to improve production efficiency, the resulting relative dielectric constant, or the capacitance Cp value of the multilayer ceramic capacitor, does not exhibit large variations relative to the temperature distribution within the furnace. Consequently, even with short firing times utilizing rapid temperature increases, larger production volumes can be achieved while ensuring sufficient reliability.

[0232] [Verification of the Effect of Gd2O3 Addition Amount]

[0233] (Example 26)

[0234] In Example 26, 0.25 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1280°C. Other conditions were the same as in Example 1.

[0235] (Example 27)

[0236] In Example 27, 1.0 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1250°C. Other conditions were the same as in Example 1.

[0237] (Example 28)

[0238] In Example 28, 2.5 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1230°C. Other conditions were the same as in Example 1.

[0239] Examples 26 to 28 are examples of dielectric ceramic compositions in which the additive amount of Gd 2 O 3 was varied within a range of 0.25 mol to 2.5 mol relative to 100 mol of BaTiO 3 .

[0240] In Examples 26 to 28, the value of Δε / °C is 2 or less, indicating that the relative dielectric constant is sufficiently stable with respect to the firing temperature. In addition, the average particle size is also 500 nm or less, and the resistivity at 150°C is also 2.0×10 8 Therefore, even in a short firing time using a high-speed temperature increase, mass production can be achieved and sufficient reliability can be obtained.

[0241] (Example 29)

[0242] In Example 29, 0.25 mol of Eu2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1290°C. Other conditions were the same as in Example 1.

[0243] (Example 30)

[0244] In Example 30, 2.5 mol of Eu2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0245] (Example 31)

[0246] In Example 31, 0.25 mol of Tb2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1280°C. Other conditions were the same as in Example 1.

[0247] (Example 32)

[0248] In Example 32, 2.5 mol of Tb2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0249] (Example 33)

[0250] In Example 33, 0.25 mol of Dy2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0251] (Example 34)

[0252] In Example 34, 2.5 mol of Dy2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1250°C. Other conditions were the same as in Example 1.

[0253] (Example 35)

[0254] In Example 35, 0.25 mol of Y2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0255] (Example 36)

[0256] In Example 36, 2.5 mol of Y2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1240°C. Other conditions were the same as in Example 1.

[0257] (Example 37)

[0258] In Example 37, 0.25 mol of Ho₂O₃, 4.0 mol of TiO₂, 1.5 mol of MnCO₃, 1.0 mol of SiO₂, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0259] (Example 38)

[0260] In Example 38, 2.5 mol of Ho₂O₃, 4.0 mol of TiO₂, 1.5 mol of MnCO₃, 1.0 mol of SiO₂, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1240°C. Other conditions were the same as in Example 1.

[0261] (Example 39)

[0262] In Example 39, 0.25 mol of Er₂O₃, 4.0 mol of TiO₂, 1.5 mol of MnCO₃, 1.0 mol of SiO₂, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0263] (Example 40)

[0264] In Example 40, 2.5 mol of Er₂O₃, 4.0 mol of TiO₂, 1.5 mol of MnCO₃, 1.0 mol of SiO₂, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1240°C. Other conditions were the same as in Example 1.

[0265] (Example 41)

[0266] In Example 41, 0.25 mol of Yb2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1260°C. Other conditions were the same as in Example 1.

[0267] (Example 42)

[0268] In Example 42, 2.5 mol of Yb2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1240°C. Other conditions were the same as in Example 1.

[0269] (Example 43)

[0270] In Example 43, 0.125 mol of Gd2O3, 0.125 mol of Dy2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0271] (Example 44)

[0272] In Example 44, 1.25 mol of Gd2O3, 1.25 mol of Dy2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1250°C. Other conditions were the same as in Example 1.

[0273] (Example 45)

[0274] In Example 45, 0.125 mol of Eu2O3, 0.125 mol of Ho2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0275] (Example 46)

[0276] In Example 46, 1.25 mol of Eu2O3, 1.25 mol of Ho2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1240°C. Other conditions were the same as in Example 1.

[0277] (Example 47)

[0278] In Example 47, 0.08 mol of Gd2O3, 0.08 mol of Tb2O3, 0.09 mol of Y2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0279] (Example 48)

[0280] In Example 48, 0.8 mol of Gd2O3, 0.8 mol of Tb2O3, 0.9 mol of Y2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962, and the firing temperature was set to 1230°C. Other conditions were the same as in Example 1.

[0281] Examples 26 to 48 are examples of dielectric ceramic compositions in which the amount of rare earth element added was varied within a range of 0.25 mol to 2.5 mol relative to 100 mol of BaTiO 3 .

[0282] In Examples 26 to 48, the value of Δε / °C is 2 or less, indicating that the relative dielectric constant is sufficiently stable with respect to the firing temperature. In addition, the average particle size is also 500 nm or less, and the resistivity at 150°C is also 2.0×10 8 Therefore, in a short firing time using a high-speed temperature rise, larger-scale production can be achieved and sufficient reliability can be obtained.

[0283] [Verification of the effect of SiO2 addition]

[0284] (Example 49)

[0285] In Example 49, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 0.2 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1290°C. Other conditions were the same as in Example 1.

[0286] (Example 50)

[0287] In Example 50, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 0.5 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1280°C. Other conditions were the same as in Example 1.

[0288] (Example 51)

[0289] In Example 51, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 2.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1220°C. Other conditions were the same as in Example 1.

[0290] (Example 52)

[0291] In Example 52, 0.75 mol of Gd2O3, 4.0 mol of TiO2, 1.5 mol of MnCO3, 5.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.962. The firing temperature was set to 1200°C. Other conditions were the same as in Example 1.

[0292] Examples 49 to 52 are examples of dielectric ceramic compositions in which the amount of SiO 2 added was varied within a range of 0.2 mol to 5.0 mol relative to 100 mol of BaTiO 3 .

[0293] In Examples 49 to 52, the value of Δε / °C was 12 or less, indicating that the relative dielectric constant was sufficiently stable with respect to the firing temperature. In addition, the average particle size was 500 nm or less, and the resistivity at 150°C was 2.0×10 8 Therefore, even in a short firing time using a high-speed temperature increase, mass production can be achieved and sufficient reliability can be obtained.

[0294] [Verification of the Effect of the Amount of TiO2 Added When Adding MgO]

[0295] (Example 53)

[0296] In Example 53, 0.75 mol of Gd2O3, 1.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.990. The firing temperature was set to 1230°C. Other conditions were the same as in Example 1.

[0297] (Example 54)

[0298] In Example 54, 0.75 mol of Gd2O3, 2.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.980. The firing temperature was set to 1240°C. Other conditions were the same as in Example 1.

[0299] (Example 55)

[0300] In Example 55, 0.75 mol of Gd2O3, 6.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.943. The firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0301] (Example 56)

[0302] In Example 56, 0.75 mol of Gd2O3, 8.0 mol of TiO2, 1.5 mol of MnCO3, 1.0 mol of SiO2, and 0.5 mol of MgO were added to 100 mol of barium titanate powder to produce a dielectric ceramic composition. The Ba / Ti element ratio was set to 0.926. The firing temperature was set to 1270°C. Other conditions were the same as in Example 1.

[0303] [Table 3]

[0304]

[0305] [Table 4]

[0306]

[0307] Examples 53 to 56 are examples of dielectric ceramic compositions in which the amount of TiO2 added per 100 mol of BaTiO3 was varied to 1.0 mol, 2.0 mol, 6.0 mol, and 8.0 mol, respectively. These examples were conducted to determine the upper and lower limits of the TiO2 content while maintaining the TiO2 content within the range of 1.0 to 8.0 mol and fixing the amounts of the other additives, Gd2O3, MnCO3, SiO2, and MgO.

[0308] The values ​​of Δε / °C for Examples 53 to 56 and Example 22 are 2 or less, indicating that the relative permittivity is extremely stable with respect to the firing temperature. In addition, the average particle size is also 500 nm or less, and the resistivity at 150°C is also 2.0×10 8 Ω·cm or more. Therefore, even in a short-time firing process using high-speed temperature increase, larger-scale production can be achieved, and sufficient reliability can be obtained. Among them, regarding Example 56, the relative dielectric constant is 2550. In Examples 53 to 56 and Example 22, the relative dielectric constant tends to decrease with increasing addition amount, so it can be seen that when the addition amount of TiO2 is more than 8.0 mol relative to 100 mol of BaTiO3, the relative dielectric constant will further decrease, so it is judged that the addition amount greater than this is outside the scope of the present invention. The addition amounts of the additives in Examples 6 to 56 mentioned above are summarized, and the firing temperature, average particle size, ε, Δε / ℃, and resistivity at 150℃ are summarized in Tables 3 and 4.

[0309] In order to confirm whether the dielectric ceramic compositions of Examples 6 to 56 have the microstructural characteristics described in the embodiment, TEM-EDS, SEM-EDS, and XRD measurements were performed to determine whether a core-shell structure and the presence of Ba4Ti 11 O 26 The results are summarized in Table 5.

[0310] [Table 5]

[0311]

[0312] In Examples 6 to 56 in Table 5, it is judged that a core-shell structure exists, and Ba4Ti 11 O 26, and the element ratio v of barium to titanium and the element ratio w of manganese to titanium in the second crystal particles 42 are in the ranges of 0.16≤v≤0.70 and 0.02≤w≤0.10, respectively, so that the presence of the second crystal particles 42 is also clear. However, in Examples 6 to 56, as shown in Table 4, the value of Δε / °C is 12 or less, and the resistivity at 150°C is 2.0×10 8 The material has a relative dielectric constant of ε>2500 and a relative dielectric constant of Ω·cm or greater, an average particle size of 500nm or less, and is therefore considered promising for use as a multilayer ceramic capacitor.

[0313] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention as described in the claims.

[0314] Explanation of symbols

[0315] 10: Main body (element body); 11: Dielectric layer; 12: Internal electrode layer; 13: Covering layer; 14: Capacitor area; 15: End edge; 16: Side edge; 20a, 20b: External electrode; 41: First crystal particle; 42: Second crystal particle; 43: Third crystal particle; 44: Gap; 51: Ceramic green sheet; 52: Internal electrode pattern; 53: Dielectric pattern; 54: Covering sheet; 55: Side edge; 100: Stacked ceramic capacitor.

Claims

1. A dielectric ceramic composition, characterized in that have: a first crystalline particle having a perovskite structure represented by the general formula ABO 3 and comprising a core portion and a shell portion covering the core portion and containing a rare earth element and manganese; and The second crystal particles contain, as a main component, a barium titanate-based composite oxide having an element ratio of barium to titanium of 0.70 or less.

2. The dielectric ceramic composition according to claim 1, wherein: The rare earth element is at least one selected from gadolinium, europium, terbium, dysprosium, holmium, erbium, and ytterbium.

3. The dielectric ceramic composition according to claim 2, wherein: The element ratio of barium to titanium is 0.926 to 0.995, the element ratio of the rare earth element to titanium is 0.005 to 0.05, and the element ratio of manganese to titanium is 0.002 to 0.

05.

4. The dielectric ceramic composition according to claim 1, wherein: It further contains silicon in an element ratio of 0.002 to 0.05 inclusive with respect to titanium, and magnesium in an element ratio of 0.00 to 0.05 inclusive with respect to titanium.

5. The dielectric ceramic composition according to claim 1, wherein: The element concentrations of the rare earth element and manganese in the shell portion are greater than the element concentrations of the rare earth element and manganese in the core portion.

6. The dielectric ceramic composition according to claim 1, wherein: The maximum particle size of the first crystal particles is 2 μm or less.

7. The dielectric ceramic composition according to claim 1, wherein: The element ratio of barium to titanium in the second crystal particles is 0.16 or more.

8. The dielectric ceramic composition according to claim 1, wherein: The second crystalline particles are selected from BaTi2O5, BaTi4O9, BaTi5O 11 、BaTi6O 13 、Ba4Ti 11 O 26 、Ba4Ti 12 O 27 、Ba4Ti 13 O 30 or Ba6Ti 17 O 40 At least one of the following.

9. The dielectric ceramic composition according to claim 1, wherein: The second crystalline particles contain manganese, The element ratio of manganese to titanium in the second crystal particles is 0.02 or more and 0.10 or less.

10. The dielectric ceramic composition according to claim 1, wherein: The second crystalline particles contain manganese, The element ratio of manganese to titanium in the second crystal particles is 0.02 or more and 0.05 or less.

11. A dielectric ceramic composition, characterized in that: have: a first crystalline particle having a perovskite structure represented by the general formula ABO 3 and comprising a core portion and a shell portion covering the core portion and containing a rare earth element and manganese; and The second crystal particle is Ba4Ti 11 O 26 The barium titanate-based composite oxide shown contains manganese, and the element ratio of manganese to titanium is 0.02 or more and 0.10 or less.

12. The dielectric ceramic composition according to claim 11, wherein: The rare earth element is at least one selected from gadolinium, europium, terbium, dysprosium, holmium, erbium, and ytterbium.

13. The dielectric ceramic composition according to claim 12, wherein: The element ratio of barium to titanium is 0.926 to 0.995, the element ratio of the rare earth element to titanium is 0.005 to 0.05, and the element ratio of manganese to titanium is 0.002 to 0.

05.

14. The dielectric ceramic composition according to claim 11, wherein: It further contains silicon in an element ratio of 0.002 to 0.05 inclusive with respect to titanium, and magnesium in an element ratio of 0.00 to 0.05 inclusive with respect to titanium.

15. The dielectric ceramic composition according to claim 11, wherein: The element concentrations of the rare earth element and manganese in the shell portion are greater than the element concentrations of the rare earth element and manganese in the core portion.

16. The dielectric ceramic composition according to claim 11, wherein: The maximum particle size of the first crystal particles is 2 μm or less.

17. The dielectric ceramic composition according to claim 11, wherein: The element ratio of manganese to titanium in the second crystal particles is 0.02 or more and 0.05 or less.

18. A laminated ceramic electronic component, characterized in that: The dielectric ceramic composition according to claim 1 is used.

19. The multilayer ceramic electronic component according to claim 18, wherein have: a plurality of internal electrodes facing each other; a dielectric layer interposed between the plurality of internal electrodes and containing the dielectric ceramic composition according to claim 1; and An external electrode is electrically connected to the internal electrode.

Images