TWI547961B - Dielectric ceramics and laminated ceramic capacitors - Google Patents

Description

Dielectric ceramics and multilayer ceramic capacitors

The present invention relates to a dielectric ceramic and a laminated capacitor. More specifically, the present invention relates to a dielectric ceramic used in an environment in which a DC (direct current) bias is applied.

The laminated ceramic capacitor which is the main use of the present invention is generally produced by the following method.

First, a ceramic green sheet containing a dielectric ceramic raw material is prepared, which has a desired pattern on its surface and is supplied with a conductive material as an internal electrode.

Next, a plurality of ceramic green sheets including ceramic green sheets having the above-mentioned conductive materials are laminated and thermocompression bonded to form an integrated unprocessed laminate.

Again, the unprocessed laminate is calcined, whereby a laminated body after sintering is obtained. An internal electrode made of the above-mentioned conductive material is formed inside the laminated body.

Then, an external electrode is formed on the outer surface of the laminated body to be electrically connected to a specific one of the internal electrodes. The external electrode is formed, for example, by applying a conductive paste containing a conductive metal powder and a glass frit to the outer surface of the laminate and sintering it. The laminated ceramic capacitor is completed in this way.

In recent years, the demand for miniaturization and large capacity of laminated ceramic capacitors has become increasingly demanding, thereby promoting thinning of the dielectric ceramic layer. With the development of the thinning of the dielectric ceramic layer, the electric field applied to the dielectric ceramic layer is relatively high, so that the insulation and reliability under high applied electric field become heavy. Want.

Patent Document 1 discloses a laminated ceramic capacitor having a dielectric constant of 3,000 or more, a room temperature of 2 kV/mm and 20 kV/mm, and a CR (capacitor resistor) product at 125 ° C. The insulation resistance (MΩ.μF) is high, 6000 is 2000 or more, and 2000 is 500 or more, and the temperature characteristics of the electrostatic capacity satisfy each standard, and the weather resistance is excellent, low cost, small size, large capacity, and reveal There is a dielectric ceramic suitable for the above, which is relative to the general formula (1-α-β-γ) [BaO] _m . TiO ₂ +αM ₂ O ₃ +βRe ₂ O ₃ +γ(Mn _1-x-y Ni _x Co _y )O (wherein M ₂ O ₃ is at least one selected from the group consisting of Sc ₂ O ₃ and Y ₂ O ₃ , Re ₂ O ₃ is at least one selected from the group consisting of Sm ₂ O ₃ and Eu ₂ O ₃ , and α, β, γ, m, x, y are 0.0025 ≦ α + β ≦ 0.025, 0 < β ≦ 0.0075, 0.0025 ≦ γ ≦0.05, γ/(α+β)≦4, 0≦x<1.0, 0≦y<1.0, 0≦x+y<1.0, 1.000<m≦1.035)

The main component is 100 mol, and the magnesium oxide as a subcomponent is converted into Mg0 and added in an amount of 0.5 to 5.0 m. Further, cerium oxide as a subcomponent is converted into SiO ₂ and 0.2 to 5.0 mol is added.

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-199748

Depending on the application of the multilayer capacitor, a fixed DC bias is always applied to the build-up capacitor. In recent years, due to the thinning of the dielectric ceramic layer, the electric field strength of the DC bias is relatively large, thereby causing a problem that the dielectric constant of the dielectric ceramic is lowered. Even for the laminated ceramic electric battery in the above Patent Document 1. In the case where the thinning is developed, the electrostatic capacitance value of the multilayer ceramic capacitor when the DC bias is applied is also lower than that without the bias voltage.

The present invention has been made in view of the above problems, and an object thereof is to provide a dielectric ceramic which exhibits a sufficient dielectric constant even under a large DC bias and a laminated ceramic capacitor using the same.

That is, the dielectric ceramic of the present invention has a composition in which a perovskite compound represented by the general formula ABO ₃ (A must contain Ba and contains at least one selected from the group consisting of Ba, Ca, and Sr; It contains Ti and contains at least one selected from the group consisting of Ti, Zr, and Hf as a main component, and contains R1 as a subcomponent (R1 is at least one selected from the group consisting of La, Nd, Sm, Gd, and Dy) and R2 ( R2 is at least one selected from the group consisting of Y, Ho, Er, and Yb, and the dielectric ceramic has crystal grains and grain boundaries, and is characterized in that it is a total of R1 of the above ABO ₃ with respect to 100 moles. When the content is set to α mol parts, and the total content of R2 is set to β mol parts, when the cross section of the crystal grains is observed, R1 is at a distance of 10 nm or more from the surface of the crystal grains toward the inside of the crystal grains. The crystal grains having a concentration of α/2 or more and a concentration of R2 of less than β/5 (including 0) are 60% or more of the total.

Further, when observing the cross section of the crystal grain, it is preferable that R2 is substantially absent from a surface of the crystal grain toward a distance of 10 nm or more from the inside of the crystal grain, and R2 exists only in the grain boundary. .

Further preferably, the above ABO ₃ is of the formula: (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y )O ₃ , and further contains M1 as a subcomponent (M1 is selected from the group consisting of V, Cr, and Mn). At least one of the types), M2 (M2 is at least 1 selected from the group consisting of Mg, Ni, Mo, and W) and Si, and the M1, M2, and Si are a moles, b, respectively, with respect to 100 moles of ABO ₃ Ears, c moles, the above x, y, m, α, β, a, b, c satisfy 0≦x≦0.05, 0≦y≦0.02, 0.99≦m≦1.03, 0.2≦α≦3.0, 0.2 ≦β≦3.0, 0.01≦a≦0.5, 0.5≦b≦2.0, 0.5≦c≦3.0.

Furthermore, the present invention is also applicable to a multilayer ceramic capacitor comprising a plurality of laminated dielectric ceramic layers, internal electrodes disposed between the dielectric ceramic layers, and external electrodes electrically connected to the internal electrodes The multilayer ceramic capacitor is characterized in that the dielectric ceramic layer is formed by the dielectric ceramic composition of the present invention.

According to the dielectric ceramic of the present invention, since the rare earth element R1 is sufficiently dissolved in the crystal grains, the rare earth element R1 is hardly dissolved in the crystal grains, and therefore, even if it is applied, the rare earth element R1 is sufficiently dissolved in the crystal grains. With a high DC bias, the dielectric constant does not decrease, thereby maintaining a high dielectric constant.

Further, in the preferred composition range of the dielectric ceramic of the present invention, a temperature change rate of a good electrostatic capacity and a high-temperature load reliability can be obtained.

Further, according to the laminated ceramic capacitor using the dielectric ceramic of the present invention, a high electrostatic capacity can be maintained even under a high DC bias.

First, a laminated ceramic capacitor which is a main application of the dielectric ceramic of the present invention will be described. Fig. 1 is a cross-sectional view showing a general laminated ceramic capacitor 1.

The multilayer ceramic capacitor 1 has a ceramic laminate 2 having a rectangular parallelepiped shape. The ceramic laminate 2 is provided with a plurality of dielectric ceramic layers 3 stacked, and along a plurality of A plurality of internal electrodes 4 and 5 formed by the interface between the dielectric ceramic layers 3. The internal electrodes 4 and 5 are formed so as to reach the outer surface of the ceramic laminate 2, and the internal electrode 4 led to the end face 6 of one of the ceramic laminates 2 and the internal electrode 5 led to the other end face 7 are attached to the ceramic laminate. The internals of 2 are alternately arranged so that the electrostatic capacitance can be obtained via the dielectric ceramic layer 3.

The conductive material of the internal electrodes 4 and 5 is preferably a low-cost nickel or nickel alloy.

In order to obtain the above electrostatic capacitance, external electrodes 8 and 9 are formed on the outer surfaces of the ceramic laminate 2 on the end faces 6 and 7, respectively, and are electrically connected to any one of the internal electrodes 4 and 5. As the conductive material contained in the external electrodes 8 and 9, a conductive material similar to the case of the internal electrodes 4 and 5 can be used, and silver, palladium, a silver-palladium alloy or the like can be used. The external electrodes 8 and 9 are formed by giving a conductive paste obtained by adding a glass frit to the metal powder as described above and sintering it.

Further, on the external electrodes 8 and 9, the first plating layers 10 and 11 made of nickel, copper, or the like are formed as needed, and the second plating layers 12 and 13 made of solder, tin, or the like are formed thereon. .

Next, the details of the dielectric ceramic of the present invention will be described.

The dielectric ceramic of the present invention has crystal grains and grain boundaries. Here, the term "grain" mainly means a crystal grain containing a main component composition, and does not correspond to a particle in which a heterophase component is precipitated. Here, the grain boundary also includes a triple point.

The main component in the composition of the dielectric ceramic of the present invention contains a perovskite compound represented by ABO ₃ , and in the detail of A, Ba is in a dominant position, and in the detail of B, Ti is in a dominant position, so BaTiO is exemplified. ₃ as a representative example. The Ba may be replaced by an element such as Sr or Ca as needed, and Ti may be substituted by an element such as Zr or Hf.

The subcomponent is characterized in that it contains two kinds of rare earth elements, that is, R1 (R1 is at least one selected from the group consisting of La, Nd, Sm, Gd, and Dy) and R2 (R2 is selected from Y, Ho, and Er). At least one of Yb). R1 is solid-solubilized in the crystal grains and has a concentration of α/2 or more. If it exists in the crystal grain at this concentration, R1 may exist in a grain boundary. On the other hand, R2 is hardly present in the crystal grains, and it mainly exists in the grain boundaries. When the concentration in the crystal grains does not reach β/5, the so-called "almost non-existent" is sufficient. If the above is satisfied, most of the R2 component added to the main component exists in the grain boundary and hardly dissolves in the crystal grains. When R1 and R2 have the above relationship at the same time, the effect of increasing the dielectric constant under the DC bias can be exhibited.

Further, when the concentration of the R2 component in the crystal grains becomes substantially zero, the decrease in the dielectric constant due to the application of the DC bias is further suppressed, which is more preferable.

Next, an example of a manufacturing method for efficiently obtaining the above dielectric ceramics will be described.

First, the raw material of the main component is synthesized. When it is assumed that the main component is BaTiO ₃ , a preferred method at this time is to mix a Ba source such as BaCO ₃ or a Ti source such as TiO ₂ , and to simultaneously mix the R 1 source such as Sm ₂ O ₃ . This was heat-treated and synthesized to form a BaTiO ₃ powder modified by R1. As a starting material and a mixing method at this time, it is generally a usual solid phase method, but it may be a wet synthesis method.

To the BaTiO ₃ powder modified by the R1, an R2 source such as Y ₂ O ₃ or the like and other auxiliary components are added and mixed, and this is used as a ceramic raw material.

Using this ceramic raw material, a ceramic slurry was produced in the same manner as before, and sheet forming was carried out to obtain a ceramic green sheet. The ceramic green sheet and the metal film were alternately laminated to obtain a molded body. Further, the metal film may be formed by coating a metal paste or may be formed by a vacuum film forming method, and thus the form thereof is not particularly limited. Then, after removing the binder from the obtained molded body in a heated environment such as the atmosphere or a nitrogen atmosphere, the molded body is fired at a temperature of about 1,000 to 1,250 °C. At this time, when the composition of the internal electrode is a base metal, it is calcined in a reducing atmosphere.

In the above calcination, since the R1 component is already present in the crystal grains containing BaTiO ₃ , the R 2 component added thereafter is hardly dissolved in the crystal grains, and is mainly present in the grain boundaries after the completion of the sintering. The R1 component already present in the crystal grains is calcined to precipitate a little in the grain boundary, but remains mainly inside the crystal grains after the completion of the sintering.

Next, better conditions in the composition of the dielectric ceramic of the present invention will be described.

First, the main component is (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y )O ₃ , and further contains M1 as a subcomponent (M1 is at least one selected from the group consisting of V, Cr, and Mn), M2. (M2 is at least one selected from the group consisting of Mg, Ni, Mo, and W) and Si, and the M1, M2, and Si are a moles, b moles, and c moles, respectively, relative to 100 moles of ABO ₃ . And x, y, m, α, β, a, b, c satisfy 0≦x≦0.05, 0≦y≦0.02, 0.99≦m≦1.03, 0.2≦α≦3.0, 0.2≦β≦3.0, 0.01≦a≦0.5, 0.5≦b≦2.0, 0.5≦c≦3.0. Within this range, the dielectric constant under the DC bias electric field is higher, and the temperature change rate of the electrostatic capacity is also good, and the high-temperature load reliability is also high.

The Ba constituting the A site of the main component may be substituted by Ca within a range satisfying 0 ≦ x ≦ 0.05. However, if x exceeds 0.05, the dielectric constant at DC bias is low.

The Ti constituting the B site of the main component may be substituted by Zr within a range satisfying 0 ≦ y 0.02. For example, when a zirconia ball is used for stirring the starting material, even if the Zr component is mixed by abrasion of the zirconia ball, there is no particular problem as long as it is within the range of 0 ≦ y 0.02.

Further, the molar ratio m of the total amount of the A component of the main component to the total amount of the B site is preferably 0.99 to 1.03. If the value of m is outside the range, the temperature change rate of the electrostatic capacity is large.

The total content α of the rare earth element R1 is preferably 0.2 ≦ α ≦ 3.0 with respect to 100 mol parts of ABO ₃ . If α is outside this range, the dielectric constant under DC bias is slightly lower.

On the other hand, the total content β of the rare earth element R2 is preferably 0.2 ≦β≦3.0 with respect to 100 mol parts of ABO ₃ . If β is outside this range, the dielectric constant under DC bias is slightly lower.

The content a of M1 relative to 100 moles of ABO ₃ is preferably 0.01 ≦ a ≦ 0.5. If a is less than 0.01, the dielectric ceramic has low reduction resistance. Further, when a exceeds 0.5, the temperature change rate of the electrostatic capacitance is large.

The content b of M2 relative to 100 moles of ABO ₃ preferably satisfies 0.5 ≦b ≦ 2.0. If b does not reach 0.5, the high temperature load reliability is low. Further, if b exceeds 2.0, the dielectric constant under DC bias is slightly lower.

Further, it is preferable that the content c of Si with respect to 100 mol parts of ABO ₃ satisfies 0.5 ≦c ≦ 3.0. If c is less than 0.5, the sintering of the dielectric ceramic is insufficient. Further, if c exceeds 3.0, the dielectric constant under DC bias is slightly lower.

[Examples]

[Experimental Example 1] This experimental example is to produce a laminated ceramic capacitor with a specific composition, and can be used as a dielectric constant state of the crystal grains of R1 and R2 to affect the dielectric constant under DC bias. The experimental composition was 100 Ba _1.00 TiO ₃ + 0.5 Sm + 1.0 Y + 0.1 Mn + 1.2 Mg + 1.2 Si. The sample is sample number 1 to 4 and 4 on it.

First, a method of producing a sample of sample No. 1 is presented. BaCO ₃ , TiO ₂ , and Sm ₂ O _{3 were} weighed as a starting material, and thoroughly mixed in a ball mill using an aqueous solvent to obtain a mixed powder. The mixed powder was calcined in the air at a temperature of 1050 ° C to obtain a main component powder.

Y ₂ O ₃ , MnCO ₃ , MgCO ₃ , and SiO _{2 were} weighed in comparison with the obtained main component powder, and were similarly mixed in a ball mill to obtain a ceramic raw material powder.

An ethanol-based organic solvent and a polyvinyl butyral-based adhesive were added to the ceramic raw material powder, and wet-mixed to obtain a ceramic slurry.

The obtained ceramic slurry was subjected to sheet forming by a doctor blade forming method to obtain a ceramic green sheet.

The obtained ceramic green sheet is cut into a specific rectangular shape, and a conductive paste containing Ni metal powder is coated on the surface thereof to have a specific pattern. The ceramic green sheets coated with the conductive paste are laminated in a plurality of pieces so that the lead-out sides are different from each other, and pressure-bonded, thereby obtaining a laminated body.

The obtained laminate is heated at a temperature of 300 ° C in a nitrogen atmosphere for debonding treatment, and is subjected to H ₂ -N ₂ -H ₂ O gas at a partial pressure of oxygen of 10 ^-9 to 10 ^-12 MPa. The composition was reduced in a reducing atmosphere at 1200 ° C for 2 hours to obtain a ceramic laminate.

Thereafter, an Ag paste containing a B ₂ O ₃ —SiO ₂ —BaO-based glass powder is applied to both end faces of the ceramic laminate, and sintered at a temperature of 600° C. in an N ₂ gas atmosphere to form a The external electrode is electrically connected to the external electrode.

For the multilayer ceramic capacitor of the sample No. 1 obtained by the above method, the outer dimension is 2.0 mm in length, 1.2 mm in width, and 1.0 mm in thickness, and the thickness of each layer of the dielectric ceramic layer is 1.5 μm, which contributes to formation. In the portion where the internal electrodes of the electrostatic capacitance are opposed, the average area per layer is 1.8 × 10 ^-6 m ² , and the number of layers of the dielectric ceramic layer contributing to the formation of the electrostatic capacity is 100.

Next, a method of producing the sample of sample numbers 2 to 4 will be described.

In the sample of sample No. 2, the calcination temperature at the time of obtaining the main component powder by calcining the mixed powder was set to 1000 °C. Except for this, the same manufacturing method as that of sample No. 1 was used.

In the sample of sample No. 3, Sm ₂ O ₃ was not mixed therein when the starting material was weighed, and Y ₂ O ₃ , MnCO ₃ , MgCO ₃ , and SiO _{2 were} mixed to a main component containing Ba _1.00 TiO ₃ . Simultaneously mixing Sm ₂ O _{3 in the} powder. Except for this, the same manufacturing method as that of sample No. 1 was used.

In the sample of sample No. 4, Y ₂ O ₃ and Sm ₂ O _{3 were} simultaneously mixed therein while weighing the starting material, and MnCO ₃ , MgCO ₃ , and SiO _{2 were} mixed to a main component containing Ba _1.00 TiO ₃ . The above mixing is not carried out in the powder. Except for this, the same manufacturing method as that of sample No. 1 was used.

The dielectric constant and high-temperature load reliability under DC bias were measured for the samples of the multilayer ceramic capacitors of the sample numbers 1 to 4 obtained, and the results are shown in Table 1. Further, the dielectric constant was measured under the conditions of a DC bias of 1.25 kV/mm and an alternating current (AC) electric field of 0.1 kV _rms / mm (at a frequency of 1 kHz). Further, the index of the high-temperature load reliability is an average failure time (h) at a temperature of 150 ° C and an AC electric field of 8 kV _rms / mm.

Then, the cross section of the sample of the multilayer ceramic capacitor of sample numbers 1 to 4 was mirror-polished. In this section, any crystal grain is selected, and TEM-EDX (using an energy-dispersive X-ray trace with a transmission electron microscope) is used for any 5 points from the grain boundary to the inside of the grain at a distance of 10 nm. Analyzer) quantitative analysis of Sm and Y. Here, when the average concentration of Sm at the measurement point of 5 points with respect to 100 moles of BaTiO ₃ is 1/2 or more of the total content α, that is, 0.25 moles or more in the present experimental example, and when 5 when the point of the measurement points in the Y relative to 100 molar parts of BaTiO ₃ average concentration of less than 1/5 of the total content of β (including 0), i.e., the present experimental example less than 0.2 mole parts, the grains As "effective grain." When the above-described measurement is performed on five crystal grains in the cross section of the sample, when the number of effective crystal grains is three or more, that is, 60% or more in terms of the number, it is considered that the sample is included in the range of the present invention. The results are shown in Table 1 below.

In the sample of sample No. 1, all of the five crystal grains were effective crystal grains, so the dielectric constant under DC bias was far more than 3,000.

In the sample No. 2, the solid solution phase of Sm in the crystal grains was slightly inferior to that of sample No. 1, but even so, 60% of the crystal grains were effective crystal grains, so the dielectric constant under DC bias exceeded 3000. .

In the sample No. 3, Sm was not sufficiently present in the crystal grains, and the effective crystal grains were only 20%, so the dielectric constant under DC bias was not even 2,500.

In the sample No. 4, Sm was sufficiently present in the crystal grains, but the solid solution promotion of Y in the crystal grains made the effective crystal grains only 20%, so the dielectric constant under DC bias was not even 2,500.

[Experimental Example 2] In the present experimental example, when the types and the number of elements of the main component and the subcomponent of the dielectric ceramic are variously changed, this can affect the characteristics. In addition, the manufacturing steps of the sample were the same as the sample No. 1 in Experimental Example 1 for all the samples.

First, weigh BaCO ₃ , CaCO ₃ , TiO ₂ , ZrO ₂ , Sm ₂ O ₃ , La ₂ O ₃ , Nd ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ as starting materials to satisfy the composition of 100 ( Ba _1-x Ca _x ) _m (Ti _1-y Zr _y )O ₃ +αR1, x, y, m, α shown in Table 2, and thoroughly mixed in a ball mill using an aqueous solvent to obtain a mixed powder . The mixed powder was calcined in the air at a temperature of 1050 ° C to obtain a main component powder.

Weighing Y ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Yb ₂ O ₃ , MnCO ₃ , Cr ₂ O ₃ , V ₂ O ₃ , MgCO ₃ , NiO, MoO ₃ with respect to the obtained main component powder , WO ₃ , SiO ₂ such that it satisfies β, a, b, c shown in Table 2 of 100(Ba _1-x Ca _x ) _m (Ti _1-y Zr _y )O ₃ +αR1+βR2+aM1+bM2+cSi, and is similarly The ball mill was mixed to obtain a ceramic raw material powder.

Using the ceramic raw material powder, samples 101 to 153 of the laminated ceramic capacitor were obtained by the same production method as the sample of the sample No. 1 of Experimental Example 1.

With respect to the samples of the multilayer ceramic capacitors of the sample numbers 101 to 153 obtained, the dielectric constant under DC bias, the temperature change rate of the electrostatic capacitance, and the high-temperature load reliability were measured, and the results are shown in Table 1. Further, the conditions of the dielectric constant and the high-temperature load reliability were the same as in Experimental Example 1. The DC bias is 1.25 kV/mm and the AC electric field is 0.1 kV _rms /mm (at a frequency of 1 kHz). The temperature change rate of the electrostatic capacity is a rate of change in electrostatic capacitance at a DC bias at -25 ° C and 85 ° C based on the electrostatic capacity at a DC bias at 20 ° C. These results are shown in Table 3.

Further, in the cross section of the sample of the multilayer ceramic capacitor of Sample Nos. 101 to 153, the concentration inside the crystal grains of R1 and R2 was quantitatively analyzed by TEM-EDX in the same manner as in Experimental Example 1. The ratio of the effective crystal grains was the same as that of the sample No. 1 of Experimental Example 1, and was 100%.

In the sample No. 101, m was less than 0.99, so the temperature change rate of the electrostatic capacity was ±30% or more, and the average failure time was less than 50 h, which was not preferable. Further, in the sample of sample No. 105, since m exceeds 1.03, the temperature change rate of the electrostatic capacitance is ±30% or more, which is not preferable.

In the samples of sample numbers 108 and 109, the substitution amount x of Ca exceeded 0.05, so the dielectric constant under DC bias was 2500 or more but less than 3,000, which was not preferable.

Samples Nos. 124 to 126 do not contain the rare earth element R1, so the dielectric constant under DC bias is less than 2,500. In the sample of sample No. 119, since the above α exceeded 3.0, the dielectric constant under DC bias was 2,500 or more but less than 3,000, which was not preferable.

In the sample Nos. 127 to 128, the total content β of the rare earth element R2 was less than 0.2, so the dielectric constant under DC bias was less than 2,500. In the sample of sample No. 131, since the above β exceeded 3.0, the dielectric constant under DC bias was 2,500 or more but less than 3,000, which was not preferable.

In the sample of sample No. 136, since the content a of M1 exceeded 0.5, the temperature change rate of the electrostatic capacity was ±30% or more, which was not preferable.

In the sample No. 142, the content b of M2 did not reach 0.5, so the average failure time was less than 50 h, which was not preferable. In the sample of sample No. 146, since the content b of M2 exceeded 2.0, the dielectric constant under DC bias was 2,500 or more but less than 3,000, which was not preferable.

In the sample of sample No. 153, since the content c of Si exceeded 3.0, the dielectric constant under DC bias was 2,500 or more but less than 3,000, which was not preferable.

Above, sample numbers 102~104, 106, 107, 110~118, The samples of 120~123, 129, 130, 132~135, 137~141, 143~145 and 147~152 show that the dielectric constant under DC bias is more than 3000, and the temperature change rate of electrostatic capacitance is less than ±30%. Moreover, the average failure time in the high temperature load test is 50 h or more, which is preferable.

1‧‧‧Laminated ceramic capacitors

2‧‧‧Ceramic laminate

3‧‧‧Dielectric ceramic layer

4, 5‧‧‧ internal electrodes

8, 9‧‧‧ external electrodes

Fig. 1 is a cross-sectional view showing a multilayer ceramic capacitor 1 according to an embodiment of the present invention.

1‧‧‧Laminated ceramic capacitors

2‧‧‧Ceramic laminate

3‧‧‧Dielectric ceramic layer

4, 5‧‧‧ internal electrodes

6, 7‧‧‧ end face

8, 9‧‧‧ external electrodes

10, 11‧‧‧1st plating

12, 13‧‧‧2nd plating

Claims (3)

A dielectric ceramic having a composition of a perovskite compound represented by the general formula ABO ₃ (A must contain Ba and contain at least one selected from the group consisting of Ba, Ca, and Sr; B must contain Ti And containing at least one selected from the group consisting of Ti, Zr, and Hf as a main component, and R1 (wherein R1 is at least one selected from the group consisting of La, Nd, Sm, Gd, and Dy) and R2 (R2 is And at least one selected from the group consisting of Y, Ho, Er, and Yb; and the dielectric ceramic has crystal grains and grain boundaries; and is characterized in that a total content of R1 of the above ABO ₃ is set relative to 100 moles When the total content of R2 is β molar, when the cross section of the crystal grains is observed, the concentration of R1 in the point from the surface of the crystal grains to the inside of the crystal grains at a distance of 10 nm or more is The crystal grains of α/2 or more and the concentration of R2 not exceeding β/5 (including 0) are 60% or more of the total, wherein the above ABO ₃ is of the formula: (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y )O ₃ and further comprising M1 (M1 is at least one selected from the group consisting of V, Cr, and Mn) and M2 (M2 is selected from the group consisting of Mg, Ni, Mo, and W) as a subcomponent of the dielectric ceramic. At least 1) and Si, the M1, M2 and Si are relative to 100 moles AB O ₃ is a molar, b molar, c molar, and the above x, y, m, α, β, a, b, and c satisfy 0≦x≦0.05, 0≦y≦0.02, 0.99. ≦m≦1.03, 0.2≦α≦3.0, 0.2≦β≦3.0, 0.01≦a≦0.5, 0.5≦b≦2.0, and 0.5≦c≦3.0. The dielectric ceramic of claim 1, wherein, when the cross section of the crystal grain is observed, substantially no R2 exists in a point from the surface of the crystal grain to the inside of the crystal grain at a distance of 10 nm or more, and R2 exists only in Grain boundaries. A multilayer ceramic capacitor comprising a plurality of laminated dielectric ceramic layers, internal electrodes disposed between the dielectric ceramic layers, and external electrodes electrically connected to the internal electrodes, wherein: The dielectric ceramic layer is formed by the dielectric ceramic of claim 1 or 2.