JP2009203110A - Dielectric ceramic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric ceramic composition in which a QXf value is improved, and further, a sufficiently high dielectric constant εr can be obtained as well. <P>SOLUTION: The dielectric ceramic composition is composed of an oxide dielectric substance expressed by compositional formula (1): a-CaO-b-LiO<SB>1/2</SB>-c-BiO<SB>3/2</SB>-d-REO<SB>3/2</SB>-e-TiO<SB>2</SB>[wherein, RE denotes at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Dy, Yb and Y, and further, a to e denote the ratio (mol%) of each component, and are values satisfying 26<a≤45, 0<b≤12, 0<c≤(a+d)/4, 0≤d≤12.5, 50≤e≤60, 0.65≤b/(c+d)<1.0, (a+b+d)/e<1.0, b≥0.9×d in the case d is not 0, and a+b+c+d+e=100]. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dielectric ceramic composition.

  In an electronic device such as a cellular phone, the frequency band used has shifted to a high frequency, and it is required to use a dielectric material having excellent dielectric characteristics in the high frequency band for a dielectric filter used in the electronic device. As such dielectric characteristics, there are mainly Q × f values (Q: quality factor, f: resonance frequency). The quality factor Q is the reciprocal of the dielectric loss tangent tan δ. The Q × f value represents the loss characteristic of the dielectric material, and the larger the value, the smaller the loss. Therefore, a dielectric filter with a small loss can be obtained by using a dielectric material having a large Q × f value.

  In recent years, electronic devices such as mobile phones are required to be downsized, and accordingly, dielectric filters are also required to be downsized. For this purpose, it is generally effective to use a dielectric material having a high relative dielectric constant εr. This is because the wavelength of the electromagnetic wave transmitted through the dielectric is shortened to 1 / √εr times according to the relative dielectric constant εr.

  From the above viewpoint, a dielectric material having a high Q × f value and a high relative dielectric constant εr is suitable for realizing a small dielectric filter having a high dielectric property. However, there is usually a trade-off relationship between the Q × f value and the relative dielectric constant εr, where one increases and the other decreases. Accordingly, development of dielectric materials has been promoted in order to realize both of these values.

For example, the applicant has the following composition formula:
_{a · CaO-b · LiO 1/2} -c · BiO 3/2 -d · REO 3/2 -e · TiO 2 ... (1)
[However, in the above formula (1), RE represents at least one rare earth element selected from the group consisting of La, Ce, Pr, Nd, Sm, Dy, Yb and Y. A to e represent the ratio (mol%) of each component, 10 ≦ a ≦ 25, 10 ≦ b ≦ 20, 8 ≦ c ≦ 15, 2 ≦ d ≦ 10, 50 ≦ e ≦ 60, 0. The relationship of 65 ≦ b / (c + d) <1.0 and a + b + c + d + e = 100 is satisfied. It is proposed to realize a dielectric ceramic having a large Q × f value, a small temperature change coefficient τf of the resonance frequency, and a high relative dielectric constant εr. (See Patent Document 1 below).
JP 2006-273703 A

  According to the dielectric ceramic composition described in Patent Document 1 described above, a dielectric material having a high Q × f value to some extent and a high relative dielectric constant εr can be provided. In recent years, however, dielectric materials may be required to have a higher Q × f value than before in order to be used at specific locations in the device. In order to meet this requirement, there is a need for a dielectric porcelain composition capable of further increasing the Q × f value and obtaining a sufficiently high relative dielectric constant εr. Yes.

  Therefore, the present invention has been made in view of such circumstances, and provides a dielectric ceramic composition capable of improving the Q × f value and obtaining a sufficiently high relative dielectric constant εr. Objective.

  In order to achieve the above object, the present inventors have further studied the ratio of the components constituting the dielectric ceramic composition represented by the composition formula (1). In particular, the composition has a large ratio of CaO. The inventors have found that a high Q × f value and a relative dielectric constant εr can be obtained by adjusting the ratio of each component to an appropriate range, and the present invention has been completed.

That is, the dielectric ceramic composition of the present invention is characterized by comprising an oxide dielectric represented by the following composition formula (1).
_{a · CaO-b · LiO 1/2} -c · BiO 3/2 -d · REO 3/2 -e · TiO 2 ... (1)
[However, in the above formula (1), RE represents at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Dy, Yb and Y. A to e represent the ratio (mol%) of each component;
26 <a ≦ 45,
0 <b ≦ 12,
0 <c ≦ (a + d) / 4,
0 ≦ d ≦ 12.5,
50 ≦ e ≦ 60,
0.65 ≦ b / (c + d) <1.0,
(A + d + b) / e <1.0,
a + b + c + d + e = 100, and
If d is not 0, b ≧ 0.9 × d,
Is a value that satisfies the relationship ]

  In addition, the composition of each element in the composition formula (1) is expressed as an analysis value obtained by performing dielectric coupling plasma emission spectroscopic analysis and fluorescent X-ray analysis on the oxide dielectric alone.

  According to the dielectric ceramic composition of the present invention having such a composition, it is possible to obtain a larger Q × f value than in the prior art and to obtain a high relative dielectric constant εr. In addition, the dielectric ceramic composition having the above composition also has a characteristic that it can be sufficiently sintered even at a lower temperature (for example, 1200 ° C. or lower) than before. Therefore, according to such a dielectric ceramic composition, when an element such as a dielectric filter is formed, efficient firing can be performed at a low temperature, and a conventional electrode material that is fired simultaneously with the dielectric ceramic composition can be used. Instead of expensive Pd and Pt, it is possible to use an Ag—Pd alloy or the like that could not be fired at a conventional high temperature because the melting point is low. As a result, the manufacturing process of elements and the like can be simplified, and it is also possible to realize cost reduction and high performance by using an Ag—Pd alloy or the like that is cheaper and has low conductor resistance.

  In the dielectric ceramic composition of the present invention, a to e in the formula (1) are more preferably values satisfying the relationship represented by 0 <c ≦ (a + d) / 5. In formula (1), a to e are more preferably values that further satisfy the relationship represented by 0.93 ≦ (a + b + c + d) / e <1. By satisfying these relationships, the Q × f value and the relative dielectric constant εr can be made compatible at a higher level.

  In the above formula (1), RE preferably contains at least Nd. In this case, at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Dy, Yb and Y is part of Nd. May be substituted. When Nd is included as RE, a particularly high Q × f value is easily obtained with a high relative dielectric constant εr.

  Furthermore, in the formula (1), a part of Ca may be substituted with at least one selected from the group consisting of Ba, Sr and Mg.

  According to the present invention, it is possible to provide a dielectric ceramic composition capable of improving the Q × f value and obtaining a sufficiently high relative dielectric constant εr.

  Hereinafter, preferred embodiments of the present invention will be described.

[Dielectric porcelain composition]
The dielectric ceramic composition of the present embodiment is made of an oxide dielectric represented by the following composition formula (1). This oxide dielectric mainly has a perovskite structure.
_{a · CaO-b · LiO 1/2} -c · BiO 3/2 -d · REO 3/2 -e · TiO 2 ... (1)
[However, in the above formula (1), RE represents at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Dy, Yb and Y. A to e represent the ratio (mol%) of each component;
26 <a ≦ 45,
0 <b ≦ 12,
0 <c ≦ (a + d) / 4,
0 ≦ d ≦ 12.5,
50 ≦ e ≦ 60,
0.65 ≦ b / (c + d) <1.0,
(A + b + d) / e <1.0,
If d is not 0, 0.9 × b> d,
a + b + c + d + e = 100,
Is a value that satisfies the relationship ]

  Ca in the oxide dielectric has an effect of improving the relative dielectric constant εr and an effect of increasing the temperature change coefficient τf of the resonance frequency to the plus side. Here, τf represents the stability of the resonance frequency f, and the smaller the absolute value of τf is, the smaller the change in dielectric characteristics with respect to temperature change is. In the oxide dielectric, when the Ca ratio is 26 mol% or less in terms of CaO, it is difficult to achieve both a high Q × f value and a high relative dielectric constant εr. On the other hand, if it exceeds 45 mol%, τf becomes too large, which is not preferable. Therefore, the content a of Ca in terms of CaO is more than 26 mol% and 45 mol% or less. In order to obtain a higher Q × f value and a relative dielectric constant εr, and to obtain a more stable temperature characteristic, the content a of Ca in terms of CaO is preferably more than 26 mol% and 40 mol% or less. preferable.

  In the oxide dielectric, part of Ca in CaO may be substituted with an alkaline earth metal element (one or more selected from Sr, Ba, and Mg). By substituting a part of Ca with an element having an ionic radius larger than Ca, such as Sr or Ba, the relative dielectric constant εr can be increased. Further, when a part of Ca is replaced with an element having an ion radius smaller than Ca, such as Mg, the Q × f value can be increased.

Li in the oxide dielectric affects the relative permittivity εr and the temperature change coefficient τf of the resonance frequency. The content b of Li in terms of LiO _1/2 is greater than 0 mol% and 12 mol% or less. When Li is not included, the temperature change coefficient τf of the resonance frequency becomes too large on the plus side. On the other hand, when it exceeds 12 mol%, the relative dielectric constant εr becomes too low.

  Bi in the oxide dielectric preferably has at least Bi since it has the effect of increasing the relative dielectric constant εr. However, if there is too much Bi, the relative dielectric constant εr rather decreases, and the Q × f value also decreases. Therefore, it is necessary to determine an appropriate amount range from the balance of εr and Q × f value.

  On the other hand, the rare earth element RE in the oxide dielectric contributes to the control of the temperature change coefficient τf of the resonance frequency, and as the amount of RE increases, the absolute value of τf tends to increase in the negative direction. However, in the composition of the present embodiment, a high Q × f value can be achieved by including a certain amount of RE.

In order to increase the Q × f value, obtain a sufficient dielectric constant εr, and obtain the temperature change coefficient τf of the minimum resonance frequency, the amounts of Ca, Bi, and RE are respectively CaO, BiO _3/2. It is desirable that the ratio of a, c and d, which is an amount converted to REO _3/2 , satisfies 0 <c ≦ (a + d) / 4, and the molar ratio of d satisfies 0 ≦ d ≦ 12.5. .

Here, in REO _3/2 , RE is preferably Nd, and a part thereof is selected from one or more of lanthanide group elements (La, Ce, Pr, Sm, Y, Yb, Dy) ) May be substituted. By setting RE to Nd, the balance between the relative dielectric constant εr, Q × f value and temperature characteristics (temperature stability) is improved, and the balance between characteristics and material cost is also improved. Further, by substituting a part of Nd with an element having an ionic radius larger than Nd, such as La, Ce, or Pr, the relative dielectric constant εr can be increased. On the other hand, by replacing a part of Nd with an element having an ion radius smaller than Nd, such as Sm, Y, Yb, and Dy, the Q × f value can be increased.

Further, when the Ti in the oxide dielectric is too much, a heterogeneous phase containing a large amount of Ti such as TiO ₂ is likely to be generated due to an excessive amount of Ti more than that required for the formation of the perovskite crystal phase. On the other hand, if the Ti content is too small, a heterogeneous phase containing a large amount of other metal elements that should enter the A site of the perovskite tends to be generated. In either case, there is a risk that the characteristics will be greatly deteriorated due to the occurrence of heterogeneous phases. Therefore, the content e of Ti in terms of TiO ₂ needs to be 50 mol% or more and 60 mol% or less.

In the oxide dielectric, the molar ratio b / (c + d) between the monovalent element Li and the sum of the trivalent element Bi and the rare earth element RE needs to be controlled within an appropriate range. First, by setting b / (c + d) <1.0, an oxide dielectric having a substantially single-phase perovskite structure can be obtained. If b / (c + d) ≧ 1, the relative dielectric constant εr decreases due to the generation of a heterogeneous phase composed of Li ₂ O.TiO ₂ . On the other hand, when Li becomes too small, that is, b / (c + d) <0.65, a heterogeneous phase such as Bi ₂ Ti ₂ O ₇ or Bi ₄ Ti ₃ O ₇ is generated, and thereby the relative dielectric constant εr and The Q × f value decreases, and the temperature change coefficient τf increases in absolute value in the plus direction. Therefore, by setting 0.65 ≦ b / (c + d) <1, a high-quality oxide dielectric is realized.

In the oxide dielectric, in the above formula (1), a, b, d and e satisfy (a + b + d) / e <1.0, and b ≧ 0.9 when d is not 0. It is preferable to satisfy xd. When b and d satisfy the relationship of b ≧ 0.9 × d, the oxide dielectric contains an excessive amount of Li that can react with Bi, and when the dielectric ceramic composition is fired, Li and Bi Since the sintering proceeds while producing a low melting point compound such as LiBiO ₂ (melting point is about 700 ° C.), low temperature firing can be achieved. Therefore, by satisfying this requirement, for example, even when the firing temperature is less than 1200 ° C., the density of the sintered body can be improved and the relative dielectric constant εr can be increased.

  In the oxide dielectric having a perovskite structure, the molar ratio A / B between A site atoms and B site atoms is greatly related to the dielectric characteristics. In the oxide dielectric contained in the dielectric ceramic composition of the present embodiment, A / B smaller than 1 is suitable for reducing the occurrence of different phases and improving the characteristics. The A site is mainly composed of Ca, Li, and RE, the B site is mainly composed of Ti, and Bi is mainly coordinated to the A site. Therefore, as described above, a, b, d, and e in the formula (1) preferably satisfy (a (Ca) + b (Li) + d (RE)) / e (Ti) <1.0.

  The dielectric ceramic composition of the present embodiment is mainly composed of the above-described oxide dielectric, but the Q × f value, the relative permittivity εr, the temperature change coefficient τf of the resonance frequency, the design firing temperature, etc. Other components may be included as long as is not significantly changed. However, from the viewpoint of obtaining sufficient characteristics, it is preferable that 90% by mole or more of the dielectric ceramic composition is composed of the oxide dielectric, and the entire amount excluding inevitable mixed components is composed of the oxide dielectric. It is particularly preferred that

[Dielectric Porcelain Composition and Dielectric Porcelain Manufacturing Method]
The dielectric ceramic composition described above and the dielectric ceramic using the same can be manufactured, for example, according to the manufacturing process shown in FIG. FIG. 1 shows a series of manufacturing processes from the production of an oxide dielectric to the production of a dielectric ceramic, and includes a mixing step 1, a pre-baking step 2, a pulverizing step 3, a granulating step 4, a molding step 5, And firing step 6. The oxide dielectric powder is produced by the steps from the mixing step 1 to the pulverizing step 3 in the manufacturing process shown in FIG.

  In manufacturing the oxide dielectric, first, a predetermined amount of the raw material powder is weighed and mixed (mixing step 1). As the raw material powder of the main component, oxide powders and compounds that become oxides upon heating, such as carbonates, hydroxides, oxalates, nitrates, and the like can be used. In this case, the raw material powder is not limited to one type of metal oxide (compound), and for example, a composite oxide powder containing two or more types of metals may be used as the raw material powder. What is necessary is just to select the average particle diameter of each raw material powder suitably in the range of 0.1 micrometer-3.0 micrometers, for example. As a mixing method, for example, wet mixing using a ball mill can be employed.

After the mixing step 1, the mixed raw material powder is appropriately dried, pulverized, and sieved. Then, the temporary baking process 2 is performed with respect to this raw material powder. In the pre-baking step 2, for example, using an electric furnace or the like, the pre-baking is performed by holding for a predetermined time in a temperature range of 900 ° C. to 1200 ° C. The atmosphere at this time may be a non-reducing atmosphere such as O ₂ , N ₂ or air. Moreover, what is necessary is just to select the holding time in calcination suitably in the range of 0.5 to 5.0 hours, for example.

  After calcination, in the pulverization step 3, the obtained calcined body is pulverized until the average particle size becomes, for example, about 0.1 μm to 2.0 μm. As the pulverizing means, for example, a ball mill or the like can be used. The oxide dielectric is obtained by the steps up to here, and the dielectric ceramic composition is obtained by using the oxide dielectric as it is or by adding other components as necessary.

  In addition, in the manufacture of the oxide dielectric, the timing of adding the raw material powder of each component is not limited only to the mixing step 1 described above. For example, only the raw material powders of some of the necessary raw material powders are weighed, mixed and calcined, pulverized, and then added with a predetermined amount of raw material powders of other components and mixed. Also good.

  After obtaining the dielectric ceramic composition in this way, the dielectric ceramic composition obtained as described above is granulated in the granulation step 4 and the granulated granules are molded in the molding step 5. Then, after obtaining a molded body having a desired shape, a dielectric ceramic can be obtained by further firing the molded body in firing step 6.

  In the granulating step 4, it is desirable to add a small amount of an appropriate binder, such as polyvinyl alcohol (PVA) or an acrylic resin, to the dielectric ceramic composition. In addition, the particle size of the obtained granule is desirably about 80 μm to 200 μm. In the molding step 5, for example, granules granulated at a pressure of 100 MPa to 300 MPa are pressure molded to obtain a molded body having a desired shape.

  And in the baking process 6, the obtained molded object is heat-held at predetermined temperature and time, the binder added at the time of shaping | molding is removed, and a sintered compact is obtained. Thereby, dielectric ceramics applied to various dielectric elements can be obtained.

Here, since the dielectric ceramic composition of the present invention has the composition of the above-described embodiment, the dielectric ceramic composition has a lower temperature than that of a dielectric material having the same Q × f value and εr. Can be fired. Therefore, the firing temperature in the firing step 6 can be performed, for example, under a temperature condition of 1200 ° C. or lower, which is a temperature lower than the melting point of the Ag (70) -Pd (30) alloy. Further, the firing atmosphere in the firing step 6 may be a non-reducing atmosphere such as O ₂ , N ₂ or air. The heating and holding time may be appropriately selected within a range of 0.5 to 6 hours, for example.

  Since the above-described dielectric ceramic composition of the present invention is composed of an oxide dielectric having a specific composition as in the above-described embodiment, although a higher Q × f value can be obtained compared to the conventional case. In addition, a sufficiently high relative dielectric constant εr can be obtained. Further, the temperature change coefficient τf of the resonance frequency can be obtained within a practical range. Furthermore, firing at 1200 ° C. or lower is also possible. Therefore, the dielectric ceramic composition of the present invention constitutes a resonator for high frequency, particularly microwaves, and a laminated dielectric filter (band-pass filter, low-pass filter, high-pass filter) using an Ag-Pd alloy as a conductor, Furthermore, in a multilayer circuit board having a configuration functioning as a dielectric filter, it is extremely suitable for a portion of a dielectric layer particularly when a high Q × f value is required.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.

[Production of Dielectric Porcelain Composition and Dielectric Porcelain]
First, high-purity CaCO ₃ , Li ₂ CO ₃ , Bi ₂ O ₃ , Nd (OH) ₃ , TiO _{2 and the} like were prepared as raw material powders. Each raw material powder had an average particle size of 0.1 to 1.0 μm.

  A predetermined amount of these raw material powders were weighed and wet mixed in ion-exchanged water for 16 hours using a ball mill. The obtained slurry was sufficiently dried, and then calcined at 1000 ° C. for 4 hours in the air to obtain a calcined body. This calcined body is wet pulverized in ion-exchanged water using a ball mill so that the average particle size is in the range of 0.5 to 1.5 μm, dried, and finely pulverized calcined powder (dielectric) A porcelain composition) was obtained. In addition, the measurement of the average particle diameter was performed using the laser diffraction type particle size distribution measuring apparatus (the Nikkiso Co., Ltd. make, MICROTRAC model 9320-X100).

  Then, after adding and granulating the obtained calcined powder with an acrylic resin as a binder, press molding was performed at a pressure of 150 MPa to obtain a cylindrical molded body. Next, this molded body was fired at 1150 ° C. for 2 hours and processed to obtain a cylindrical sintered body sample (dielectric ceramic) having a diameter: height = 2: 1. The composition of the dielectric ceramic thus produced was confirmed by an X-ray fluorescence analyzer (manufactured by Rigaku Corporation, ZSX-100e) and an inductively coupled plasma emission spectrometer (ICP-AES) apparatus (ICPS-8000, manufactured by Shimadzu Corporation). .

Tables 1 and 2 show a list of compositions of various dielectric ceramics obtained by the above manufacturing method. In Tables 1 and 2, the element symbol described in the column of REO _3/2 indicates the type of element blended as RE. The meanings of the symbols “<” and “>” attached to the columns “(a + d) / 5” and “(a + d) / 4” are as follows. That is, when the amount of BiO _3/2 shown on the left side of the column (that is, the value of c) is smaller than “(a + d) / 5” or “(a + d) / 4”, it is indicated by “<”. If it is large, it is indicated by “>”.

Furthermore, in Table 2, for B1 to B7, the “replacement” column on the right side of CaO is blank, which means that a part of Ca is not replaced by Ba, Sr, Mg, or the like. To express. For B8 to B10, the right column of REO _3/2 is blank. This is because all of RE is Nd, and part of RE is La, Ce, Pr, Sm, Dy, It is not substituted by Yb, Y or the like.

[Characteristic evaluation]
The dielectric properties (relative permittivity εr and Q × f value) of the various dielectric ceramics obtained were measured. Dielectric characteristics were measured by the Hakki-Coleman method. The measuring instrument used is a network analyzer (manufactured by Hewlett-Packard Company, 8510C). In addition, the resonant frequency at the time of measurement was 3-5 GHz.

Regarding the relative density, among the sintered body samples fired at 1000 to 1400 ° C. for 2 hours, the density of the most dense sample is defined as 100%, and the density obtained from the weight and dimensions of the actual sintered body Were compared to calculate the relative density. The obtained results are summarized in Tables 3 and 4.

  As shown in Table 3 and Table 4, obtained using the dielectric ceramic composition of A3 to A6, A8 to A13, A15 to A20, A22 to A27, B1 to B10 of Examples included in the composition range of the present invention. Compared with the case of using the dielectric ceramic composition of the comparative example which is outside the composition range of the present invention, the obtained dielectric ceramic can obtain a high Q × f value as a whole and has a sufficiently high relative dielectric constant εr. It was confirmed that When the dielectric ceramic compositions of A1, A2, A7, A14, and A21 were used, sintering was insufficient, and a dielectric ceramic that could sufficiently exhibit dielectric characteristics was not obtained.

  In addition, the dielectric ceramic compositions of A20, A26 and A27, that is, those in which c exceeds (a + d) / 5 have a Q × f value as compared with the case of using the dielectric ceramic composition of other examples. From this, it was found that particularly excellent Q × f values can be obtained when c is (a + d) / 5 or less. Furthermore, from the results of Table 4, even if a part of Ca is replaced with another alkaline earth metal element and a part of Nd is replaced with another rare earth element, a high Q × f value and a high relative dielectric constant εr Was confirmed to be sufficiently obtained.

It is a flowchart which shows a series of manufacturing processes from preparation of an oxide dielectric material to preparation of a dielectric ceramic.

Claims (6)

A dielectric ceramic composition comprising an oxide dielectric represented by the following composition formula (1):
_{a · CaO-b · LiO 1/2} -c · BiO 3/2 -d · REO 3/2 -e · TiO 2 ... (1)
[However, in the above formula (1), RE represents at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Dy, Yb and Y. A to e represent the ratio (mol%) of each component;
26 <a ≦ 45,
0 <b ≦ 12,
0 <c ≦ (a + d) / 4,
0 ≦ d ≦ 12.5,
50 ≦ e ≦ 60,
0.65 ≦ b / (c + d) <1.0,
(A + b + d) / e <1.0,
If d is not 0, b ≧ 0.9 × d,
a + b + c + d + e = 100
Is a value that satisfies the relationship ] In the formula (1), a to e are represented by the following formula:
0 <c ≦ (a + d) / 5
The dielectric ceramic composition according to claim 1, wherein the dielectric ceramic composition satisfies a relationship represented by: In the formula (1), a to e are represented by the following formula:
0.93 ≦ (a + b + c + d) / e <1
The dielectric ceramic composition according to claim 1, wherein the dielectric ceramic composition further satisfies a relationship represented by:   The dielectric ceramic composition according to any one of claims 1 to 3, wherein RE in the formula (1) includes at least Nd.   5. The RE according to claim 4, wherein a part of the Nd is substituted with at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Dy, Yb, and Y in the RE. Dielectric ceramic composition.   In said Formula (1), a part of Ca is substituted by at least 1 sort (s) chosen from the group which consists of Ba, Sr, and Mg, As described in any one of Claims 1-5 characterized by the above-mentioned. Dielectric ceramic composition.

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