KR101624080B1 - Dielectric ceramic composition and electronic device - Google Patents

Abstract

Disclosed is a dielectric ceramic composition exhibiting a high AC breakdown voltage while satisfactorily maintaining various characteristics, and providing an electronic part in which the dielectric ceramic composition is applied to a dielectric layer.
(Solution) A dielectric ceramic composition containing a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ and an oxide of Zn. X in the composition formula is 0.970 to 0.996, and y is 0.050 to 0.130. Zn oxide is 1.5 to 8.0 parts by weight in terms of ZnO based on 100 parts by weight of the compound. The dielectric ceramic composition is preferably added with respect to Nb-containing oxide, and Nb oxide content of this compound in 100 parts by weight of not more than 0.6 parts by weight as Nb ₂ O ₅ basis.

Description

[0001] Dielectric ceramic composition and electronic device [0002]

The present invention relates to a dielectric ceramic composition and an electronic component in which the dielectric ceramic composition is applied to a dielectric layer. Specifically, the present invention relates to a dielectric ceramic composition exhibiting a high AC breakdown voltage while maintaining various characteristics well, and an electronic component to which the dielectric ceramic composition is applied.

BACKGROUND ART [0002] Ceramic capacitors as an example of ceramic electronic components are widely used as small-sized, high-performance, and highly reliable electronic components, and many of them are used in electric devices and electronic devices. 2. Description of the Related Art Recently, with the miniaturization and high performance of devices, there has been a growing demand for miniaturization, high performance, and high reliability of ceramic capacitors.

For example, high-voltage ceramic capacitors used at high voltage are mainly used in power transmission and distribution facilities and facilities for processing pulse energy.

As the high-voltage ceramic capacitor, for example, a through-type ceramic capacitor is exemplified. The through-type ceramic capacitor is used to cut off high-frequency noise leaking from the magnetron provided in the microwave oven. Since the element body of the capacitor continuously receives charges generated by the high voltage, insulation breakdown may occur in the dielectric layer of the element body. If such an insulation breakdown occurs, the microwave oven may fail and there is a risk of fire or electric shock.

Therefore, in order to prevent dielectric breakdown of the dielectric layer, it is necessary to apply a dielectric ceramic composition having a good withstand voltage property to the dielectric layer. In order to suppress the heat generation of the capacitor, a dielectric ceramic composition having a low dielectric loss is required. Furthermore, a dielectric ceramic composition requires a high relative dielectric constant in order to increase the effect of blocking high-frequency noise or to meet the demand for miniaturization.

In respect to such requirements, for example, Patent Document 1 has a composition formula _{(Ba 1- xCa x) (Ti} 1-y Zr y) O ₃ as a main component indicates, the addition of rare earth element and, Fe, Ni and Zn ceramic capacitor . In the example of Patent Document 1, a sample having a relative dielectric constant of 10000 or more is described. However, the samples described in the examples often have a dielectric loss exceeding 1% and an AC breakdown voltage of 5 kV / mm or so.

Patent Document 2 discloses a ceramic capacitor in which a rare earth element, Mg, Fe, Ni and Zn are added as a subcomponent to the main component represented by the composition formula (1-α) BaTiO _{3 -} αBaZrO ₃ . The relative dielectric constant of the sample described in the example of Patent Document 2 is about 3500. In addition, the dielectric loss of many samples exceeds 1%, and the AC breakdown voltage is also about 6 kV / mm.

Patent Document 3 discloses a dielectric ceramic composition in which BaTiO ₃ is mainly composed of a composition containing Bi, Sn, Zr, Al, Si, and Mn as main components and Li, Fe, Ni, Zn, Sr, La, Compositions are described.

However, in the case of using at a higher voltage, the capacitors described in Patent Documents 1 and 2 have a problem that the AC breakdown voltage is insufficient. The dielectric ceramic composition disclosed in Patent Document 3 is not for high voltage but for temperature compensation and has not been evaluated at all for AC breakdown voltage.

Patent Document 1: JP-A-2006-96576 Patent Document 2: JP-A-2005-67941 Patent Document 3: JP-A-52-92400

It is an object of the present invention to provide a dielectric ceramic composition exhibiting a high AC breakdown voltage while keeping various characteristics satisfactory in view of the above fact and to provide an electronic component in which the dielectric ceramic composition is applied to a dielectric layer .

That is, the present invention for solving the above problems is as follows.

(1) A dielectric ceramic composition containing a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ and an oxide of Zn,

X in the composition formula is 0.970 to 0.996, y is 0.050 to 0.130,

The dielectric ceramic composition according to claim 1, wherein the oxide content of Zn is 1.5 to 8.0 parts by weight in terms of ZnO based on 100 parts by weight of the compound.

(2) The dielectric ceramic composition according to 0.6 parts by weight or less of (1) the Nb ₂ O ₅ equivalent with respect to the dielectric ceramic composition is added to the oxide content of the Nb above compound 100 parts by weight of an oxide of Nb, and a.

(3) The dielectric ceramic composition according to (2), wherein the dielectric ceramic composition further contains an oxide of Si, and the oxide content of Si is 2.0 parts by weight or less in terms of SiO _{2 based} on 100 parts by weight of the compound.

(4) The dielectric ceramic composition as described in (2) above, wherein the dielectric ceramic composition further contains an oxide of Al, and the oxide content of Al is 0.8 parts by weight or less in terms of Al ₂ O _{3 based} on 100 parts by weight of the compound.

(5) The dielectric ceramic composition according to (2), wherein the dielectric ceramic composition further contains an oxide of Ga, and the oxide content of the Ga is 0.4 parts by weight or less in terms of Ga ₂ O _{3 based} on 100 parts by weight of the compound.

(6) A dielectric ceramic composition containing a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ , a composite oxide of Zn and Si, and an oxide of Nb,

X in the composition formula is 0.970 to 0.996, y is 0.050 to 0.130,

The content of the composite oxide of Zn and Si is 0.5 to 4.2 parts by weight in terms of Zn ₂ SiO _{4 based} on 100 parts by weight of the compound,

The oxide content of the Nb based on 100 parts by weight of the compound greater than 0.6 parts by weight as Nb ₂ O ₅ in terms of the dielectric ceramic composition.

(7) A dielectric ceramic composition containing a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ , a composite oxide of Zn, Ba and Si, and an oxide of Nb,

X in the composition formula is 0.970 to 0.996, y is 0.050 to 0.130,

And a composite oxide content of the Zn and Ba and Si 1.5~9.8 parts by weight in terms BaZnSiO ₄ with respect to 100 parts by weight of the compound,

The oxide content of the Nb based on 100 parts by weight of the compound greater than 0.6 parts by weight as Nb ₂ O ₅ in terms of the dielectric ceramic composition.

(8) A dielectric ceramic composition containing a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ , a composite oxide of Zn and Al, and an oxide of Nb,

X in the composition formula is 0.970 to 0.996, y is 0.050 to 0.130,

The content of the composite oxide of Zn and Al is 1.5 to 9.8 parts by weight in terms of ZnAl ₂ O _{4 based} on 100 parts by weight of the compound,

The oxide content of the Nb based on 100 parts by weight of the compound greater than 0.6 parts by weight as Nb ₂ O ₅ in terms of the dielectric ceramic composition.

(9) A dielectric ceramic composition containing a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ , a composite oxide of Zn and Ga, and an oxide of Nb,

X in the composition formula is 0.970 to 0.996, y is 0.050 to 0.130,

And a composite oxide content of the Zn and Ga 1.5~9.8 parts by weight of the ZnGa ₂ O ₄ in terms of, based on 100 parts by weight of the compound,

The oxide content of the Nb based on 100 parts by weight of the compound greater than 0.6 parts by weight as Nb ₂ O ₅ in terms of the dielectric ceramic composition.

(10) An electronic component having a dielectric layer composed of the dielectric ceramic composition according to any one of (1) to (9).

In the present invention, a dielectric ceramic composition having various characteristics can be obtained by setting x and y in the above composition formula within the above range, and further adjusting the content of Zn oxide or the complex oxide of Zn given above within the above range . A dielectric ceramic composition exhibiting a particularly high breakdown voltage can be obtained.

The dielectric ceramic composition according to the present invention can further improve the characteristics by further containing the above components.

The electronic component according to the present invention has a dielectric layer composed of the dielectric ceramic composition described in any of the above. The electronic component related to the present invention is preferable as an electronic component for high voltage. Specifically, a through-type ceramic capacitor, a single plate ceramic capacitor, a multilayer ceramic capacitor, and the like are exemplified.

Fig. 1 (A) is a front view of a ceramic capacitor according to an embodiment of the present invention, and Fig. 1 (B) is a side sectional view of a ceramic capacitor according to an embodiment of the present invention.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.

First Embodiment

(Ceramic capacitor 2)

1 (A) and 1 (B), a ceramic capacitor 2 according to the present embodiment includes a dielectric layer 10, a pair of terminal electrodes 12 and 14 formed on the surface of the dielectric layer 10, Lead terminals 6 and 8 connected to the terminal electrodes 12 and 14, respectively, and a protective resin 4 covers the terminals. The shape of the ceramic capacitor 2 may be suitably determined in accordance with the purpose or use. In this embodiment, a single plate capacitor in which the dielectric layer 10 has a disk shape is exemplified. In addition, the size thereof may be suitably determined in accordance with the purpose or use.

(Dielectric layer 10)

The dielectric layer 10 is composed of the dielectric ceramic composition according to the present embodiment. The dielectric ceramic composition has a compound represented by the composition formula Ba _x (Ti _1-y Sn _y ) O ₃ and an oxide of Zn.

The compound has a perovskite type crystal structure. In addition, Ba may not necessarily be located at the A site of the perovskite-type crystal structure, and Ti and Sn may not always be located at the B site of the perovskite-type crystal structure.

In the above formula, x is 0.970 to 0.996, preferably 0.975 to 0.988. x represents Ba / (Ti + Sn) which represents the molar ratio of the Ba atom to the Ti atom and Sn atom, and x is in the above range, the dielectric loss is further lowered.

In the above formula, y is 0.050 to 0.130, preferably 0.090 to 0.100. y represents the ratio of Sn in the B-site atoms, and y is in the above-mentioned range, which has the advantage of further increasing the relative dielectric constant.

The oxide content of Zn is 1.5 to 8.0 parts by weight, preferably 3.5 to 8.0 parts by weight, in terms of ZnO, based on 100 parts by weight of the compound. In this embodiment, the oxide content of Zn to the compound is relatively large. By doing so, it is possible to improve the AC breakdown voltage, in particular, while maintaining the relative dielectric constant, dielectric loss and capacitance-temperature characteristics well.

It is preferable that the dielectric ceramic composition according to the present embodiment further contains an oxide of Nb.

The oxide content of Nb is 0.6 parts by weight or less, preferably 0.2 to 0.5 parts by weight, calculated as Nb ₂ O _{5 based} on 100 parts by weight of the compound. By containing the oxide of Nb in the above range, the relative dielectric constant can be increased, and further, the dielectric loss can be reduced.

The dielectric ceramic composition according to the present embodiment preferably contains an oxide of any of Si, Al, and Ga.

The oxide content of Si is 2.0 parts by weight or less, preferably 0.5-1.0 parts by weight in terms of SiO _{2 based} on 100 parts by weight of the compound. By containing the Si oxide within the above range, the dielectric loss can be reduced while maintaining the relative dielectric constant.

The oxide content of Al is 0.8 parts by weight or less, preferably 0 to 0.1 parts by weight, more preferably 0 parts by weight or more and 0.1 parts by weight or less, based on 100 parts by weight of the above compound, in terms of Al ₂ O ₃ . By containing an oxide of Al within the above range, the relative dielectric constant can be increased.

The oxide content of Ga is 0.4 parts by weight or less, preferably 0 to 0.1 parts by weight, more preferably 0 parts by weight or more and 0.1 parts by weight or less, based on 100 parts by weight of the above compound, in terms of Ga ₂ O ₃ . By containing an oxide of Ga in the above range, the relative dielectric constant can be increased.

The thickness of the dielectric layer 10 is not particularly limited and may be suitably determined in accordance with the use or the like.

(The terminal electrodes 12 and 14)

The terminal electrodes 12 and 14 are made of a conductive material. The conductive material used for the terminal electrodes 12 and 14 includes, for example, Cu, a Cu alloy, Ag, an Ag alloy, an In-Ga alloy, or the like as a main component. Of these, Cu and Cu alloys are preferable. The terminal electrodes 12 and 14 may be a single layer made of these metals or alloys or may be composed of a plurality of conductive materials.

(Manufacturing Method of Ceramic Capacitor)

Next, a manufacturing method of the ceramic capacitor according to the present embodiment will be described. First, a dielectric material used for forming the dielectric layer 10 shown in FIG. 1 is prepared after firing.

First, a raw material for each component constituting the dielectric ceramic composition is prepared. The raw materials to be used are not particularly limited, and oxides and complex oxides of the above-mentioned respective components, or compounds which become these oxides or composite oxides by firing can be used. Examples of the compound include carbonates, nitrates, hydroxides, organometallic compounds and the like. In the present embodiment, an oxide such as a carbonate such as BaCO ₃ or an oxide such as SnO ₂ , TiO ₂ , ZnO, Nb ₂ O ₅ , SiO ₂ , Al ₂ O ₃ , or Ga ₂ O ₃ or the above- Can be used.

Subsequently, the raw material of the compound represented by the composition formula Ba _x (Ti _1-y Sn _y ) O ₃ is compounded so as to have the above-mentioned predetermined composition, and wet-mixed using a ball mill or the like. The obtained mixture is assembled, and the granulated product is molded to obtain a molded product. The preform is fired in air to obtain a preliminary fired component (fired powder). Subsequently, the obtained preheater component is roughly pulverized, a predetermined amount of the remaining raw material is further added, and wet mixed to obtain a dielectric raw material. The prebaking condition is, for example, a prebaking temperature of preferably 900 to 1200 占 폚 and a prebaking time of preferably 0.5 to 4 hours.

Subsequently, a binder or the like is added to the obtained dielectric material to assemble it, and the obtained granulated material is molded into a disk having a predetermined size to obtain a molded article. Then, the obtained molded body is fired to obtain a dielectric ceramic composition as a sintered body. The firing conditions are not particularly limited, but it is preferable to set the holding temperature to 1200 to 1340 DEG C, and it is preferable to set the firing atmosphere to air.

Then, the terminal electrodes are printed on the main surface of the obtained sintered body, and baked as necessary to form the terminal electrodes 12 and 14. [ Thereafter, the lead terminals 6 and 8 are joined to the terminal electrodes 12 and 14 by soldering or the like and finally the element body is covered with the protective resin 4, To obtain a veneer ceramic capacitor.

The ceramic capacitor of the present embodiment manufactured in this way is mounted on a printed board or the like via the lead terminals 6 and 8 and is used in various electronic apparatuses and the like.

Second Embodiment

The dielectric ceramic composition according to the present embodiment is the same as the first embodiment except that it has a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ , a composite oxide of Zn and Si, and an oxide of Nb , And redundant explanations are omitted.

In the above formula, x is 0.970 to 0.996, preferably 0.975 to 0.988. x represents Ba / (Ti + Sn) which represents the molar ratio of the Ba atom to the Ti atom and Sn atom, and x is in the above range, the dielectric loss is further lowered.

In the above formula, y is 0.050 to 0.130, preferably 0.090 to 0.100. y represents the ratio of Sn in the B-site atoms, and y is in the above-mentioned range, which has the advantage of further increasing the relative dielectric constant.

The composite oxide content of Zn and Si is 0.5 to 4.2 parts by weight, preferably 0.5 to 3.7 parts by weight, in terms of Zn ₂ SiO _{4, based} on 100 parts by weight of the above compound. By setting the content of the composite oxide of Zn and Si within the above-mentioned range, it is possible to improve the AC breakdown voltage, while keeping the dielectric constant, the dielectric loss and the temperature-temperature characteristics satisfactorily.

The oxide content of Nb is 0.6 parts by weight or less, preferably 0.2 to 0.5 parts by weight, calculated as Nb ₂ O _{5 based} on 100 parts by weight of the compound. By containing the oxide of Nb in the above range, the relative dielectric constant can be increased, and further, the dielectric loss can be reduced.

Third Embodiment

The dielectric ceramic composition according to the present embodiment has the same composition as that of the first embodiment except that the compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ , the composite oxide of Zn, Ba and Si, And redundant descriptions are omitted.

In the above formula, x is 0.970 to 0.996, preferably 0.975 to 0.988. x represents Ba / (Ti + Sn) which represents the molar ratio of the Ba atom to the Ti atom and Sn atom, and x is in the above range, the dielectric loss is further lowered.

In the above formula, y is 0.050 to 0.130, preferably 0.090 to 0.100. y represents the ratio of Sn in the B-site atoms, and y is in the above-mentioned range, which has the advantage of further increasing the relative dielectric constant.

A composite oxide content of Zn and Ba, and Si is the compound to 100 parts by weight of 1.5 to 9.8 parts by weight with respect to terms BaZnSiO _4, preferably from 4.9 to 7.4 parts by weight. By setting the content of the composite oxide of Zn and Ba and Si within the above range, it is possible to improve the AC breakdown voltage particularly while maintaining the dielectric constant, the dielectric loss, and the capacity-temperature characteristics.

The oxide content of Nb is 0.6 parts by weight or less, preferably 0.2 to 0.5 parts by weight, calculated as Nb ₂ O _{5 based} on 100 parts by weight of the compound. By containing the oxide of Nb in the above range, the relative dielectric constant can be increased, and further, the dielectric loss can be reduced.

Fourth Embodiment

The dielectric ceramic composition according to the present embodiment is the same as the first embodiment except that it has a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ , a composite oxide of Zn and Al, and an oxide of Nb , And redundant explanations are omitted.

In the above formula, x is 0.970 to 0.996, preferably 0.975 to 0.988. x represents Ba / (Ti + Sn) which represents the molar ratio of the Ba atom to the Ti atom and Sn atom, and x is in the above range, the dielectric loss is further lowered.

In the above formula, y is 0.050 to 0.130, preferably 0.090 to 0.100. y represents the ratio of Sn in the B-site atoms, and y is in the above-mentioned range, which has the advantage of further increasing the relative dielectric constant.

The content of the complex oxide of Zn and Al is 1.5 to 9.8 parts by weight, preferably 4.9 to 7.4 parts by weight, in terms of ZnAl ₂ O ₄ , relative to 100 parts by weight of the compound. By setting the content of the composite oxide of Zn and Al within the above range, it is possible to improve the AC breakdown voltage particularly while maintaining the relative dielectric constant, dielectric loss and capacity-temperature characteristics.

The oxide content of Nb is 0.6 parts by weight or less, preferably 0.2 to 0.5 parts by weight, calculated as Nb ₂ O _{5 based} on 100 parts by weight of the compound. By containing the oxide of Nb in the above range, the relative dielectric constant can be increased, and further, the dielectric loss can be reduced.

Fifth Embodiment

The dielectric ceramic composition according to the present embodiment is the same as the first embodiment except that it has a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ , a composite oxide of Zn and Ga, and an oxide of Nb , And redundant explanations are omitted.

In the above formula, x is 0.970 to 0.996, preferably 0.975 to 0.988. x represents Ba / (Ti + Sn) which represents the molar ratio of the Ba atom to the Ti atom and Sn atom, and x is in the above range, the dielectric loss is further lowered.

In the above formula, y is 0.050 to 0.130, preferably 0.090 to 0.100. y represents the ratio of Sn in the B-site atoms, and y is in the above-mentioned range, which has the advantage of further increasing the relative dielectric constant.

A composite oxide content of Zn and Ga is, the compound to 100 parts by weight of 1.5 to 9.8 parts by weight of the ZnGa ₂ O ₄ for the conversion, preferably from 4.9 to 7.4 parts by weight. By setting the content of the composite oxide of Zn and Ga within the above range, it is possible to improve the AC breakdown voltage, while maintaining the relative dielectric constant, dielectric loss and capacity-temperature characteristics favorably.

The oxide content of Nb is 0.6 parts by weight or less, preferably 0.2 to 0.5 parts by weight, calculated as Nb ₂ O _{5 based} on 100 parts by weight of the compound. By containing the oxide of Nb in the above range, the relative dielectric constant can be increased, and further, the dielectric loss can be reduced.

Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to these embodiments at all and can be carried out in various different modes within the scope of the present invention.

For example, in the above-described embodiment, a single-plate ceramic capacitor is exemplified as an electronic component according to the present invention. However, the electronic component related to the present invention is not limited to a single-plate ceramic capacitor, and a dielectric paste And a multilayer ceramic capacitor manufactured by a typical printing method or sheet method using an electrode paste.

[Example]

Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

(Example 1)

First, BaCO ₃ powder, SnO ₂ powder and TiO ₂ powder were prepared as raw materials of a compound represented _{by the} composition formula Ba _x (Ti _{1 -y} Sn _y ) O ₃ . In addition, ZnO powder was prepared as an oxide raw material of Zn.

Next, the raw material powder of the compound prepared above was weighed, wet-mixed, pulverized and dried for 8 hours by a ball mill using a ball made of zirconia to obtain a raw material mixture. 5 wt% of water was added to the obtained raw material mixture and granulated to prepare granules, and the granules were molded. Then, the obtained molded product was prefired in air at 1150 캜 for 2 hours. The powder after the pre-firing was roughly pulverized by a pulverizer, passed through a mesh pass, and then the remaining raw material ZnO powder was weighed and added to perform wet pulverization. This was dried to obtain a dielectric material.

Next, 10% by weight of a polyvinyl alcohol aqueous solution was added to 100% by weight of the obtained dielectric material, assembled, and passed through a mesh pass. Thereafter, the resulting granules were molded at a pressure of 396 MPa to obtain a molded article having a diameter of 16.5 mm and a thickness of about 1.2 mm.

Subsequently, the obtained molded body was fired in air at a temperature of 1200 to 1350 占 폚 for 2 hours to obtain a sintered body on a disk. Then, Ag electrode was coated on the main surface of the obtained sintered body, and the Ag electrode was further baked in the air at 800 DEG C for 10 minutes to obtain a sample of the ceramic capacitor on the disk shown in Fig. 1 (Sample Nos. 1 to 28 ).

The composition of the obtained sintered body was confirmed to be the composition shown in Table 1 by a glass bead method by using a fluorescent X-ray analyzer (Semaritix 12 manufactured by Rigaku Corporation). The thickness of the dielectric layer 10 of the obtained capacitor sample was about 1 mm, and the diameter of the electrode was 12 mm. Then, relative dielectric constant, dielectric loss, AC breakdown field and capacity-temperature characteristics of each of the obtained capacitor samples were evaluated by the following methods.

(Relative dielectric constant epsilon)

The relative dielectric constant epsilon was measured for a capacitor sample under a condition of a frequency of 1 kHz and an input signal level (measurement voltage) of 1.0 Vrms using a digital LCR meter (4284A, manufactured by Agilent Technologies) . The relative dielectric constant is preferably high, and in the present embodiment, 4000 or more is good. The results are shown in Table 1.

(Dielectric loss)

The dielectric loss (tan delta) was measured for a capacitor sample under a condition of a frequency of 1 kHz and an input signal level (measurement voltage) of 1.0 Vrms using a digital LCR meter (4284A, manufactured by Agilent Technologies) at a reference temperature of 25 ° C . The dielectric loss is preferably low, and in the present embodiment, 0.80% or less is good. The results are shown in Table 1.

(Temperature characteristic of capacitance)

The capacitor samples were measured for electrostatic capacities in the temperature range of -25 to 85 캜 and the rate of change ΔC for electrostatic capacitance at 20 캜 was calculated to evaluate whether or not the E characteristics of the JIS standard were satisfied. That is, it was evaluated whether or not the rate of change? C in the temperature range was within -55 to + 20%. The results are shown in Table 1.

(AC breakdown voltage)

The AC breakdown voltage (ACVB) was measured by applying an alternating electric field at a rate of about 184 V / s using a SM20051 type AC internal pressure gauge (Tamadensoku) on both end faces of a capacitor sample, and when a leakage current flowing therethrough reached 100 mA Was measured, and the measured value was taken as an AC breakdown voltage. In this embodiment, 7.0 kV / mm or more is good. The results are shown in Table 1.

It can be seen from Table 1 that in the dielectric ceramic composition (sintered body), when the "x" in the composition formula, the "y" in the composition formula and the oxide content of Zn are within the above-described ranges (Sample Nos. 2 to 8, 14 to 17 and 22 to 27), it was confirmed that a dielectric ceramic composition exhibiting a high AC breakdown voltage can be obtained while satisfactorily maintaining the relative dielectric constant, dielectric loss and capacity-temperature characteristics.

In contrast, when "x" in the composition formula was too small (sample number 1), it was confirmed that the dielectric loss and the capacity temperature characteristics deteriorated. When "x" in the composition formula is excessively large (sample Nos. 9 to 12), the dielectric ceramic composition is deformed and the characteristics can not be evaluated, or at least one of the dielectric constant, dielectric loss, AC breakdown voltage, .

From Table 1, it was confirmed that the relative dielectric constant and dielectric loss deteriorated when "y" in the composition formula was excessively small (Sample No. 13). In addition, when "y" in the composition formula was too large (Sample Nos. 18 and 19), it was confirmed that the relative dielectric constant and the capacity-temperature characteristics deteriorated.

From Table 1, it was confirmed that when the oxide content of Zn is too small (Sample Nos. 20 and 21), the relative dielectric constant deteriorates and the AC breakdown voltage decreases. When the content of Zn oxide was too large (Sample No. 28), it was confirmed that the relative dielectric constant deteriorated.

(Example 2)

Except that Nb ₂ O ₅ powder as an oxide raw material of Nb was prepared and Nb ₂ O ₅ powder was weighed and added to the pre-baked powder together with ZnO powder to perform wet pulverization. (Samples Nos. 30 to 35) were obtained.

The composition of the obtained sintered body was confirmed to be the composition shown in Table 2 by the same method as in Example 1. The relative dielectric constant, dielectric loss, AC breakdown field and capacity-temperature characteristics of each of the obtained capacitor samples were evaluated in the same manner as in Example 1, respectively. The results are shown in Table 2.

From Table 2, it was confirmed that the relative dielectric constant and dielectric loss can be improved while maintaining the AC breakdown voltage and the capacity-temperature characteristic by further containing an oxide of Nb (Sample Nos. 30 to 34). In addition, when the oxide content of Nb was excessively large (Sample No. 35), it was confirmed that the relative dielectric constant deteriorated.

(Example 3)

As oxide raw material of Si prepare a Ga ₂ O ₃ powder as the oxide material of the Al ₂ O ₃ powder, and Ga as the oxide material of SiO ₂ powder, Al, respectively, with respect to the powder after the calcination ZnO powder and Nb ₂ O ₅ powder (Sample Nos. 40 to 51) of ceramic capacitors were prepared in the same manner as in Example 1, except that SiO ₂ powder, Al ₂ O ₃ powder or Ga ₂ O ₃ powder was weighed and added and wet pulverized, .

The composition of the obtained sintered body was the composition shown in Table 3 by the same method as in Example 1. Dielectric constant, dielectric loss, AC breakdown field and capacity-temperature characteristics of each of the obtained capacitor samples were evaluated in the same manner as in Example 1, respectively. The results are shown in Table 3.

From Table 3, it was confirmed that the dielectric loss can be improved while maintaining the AC breakdown voltage, the capacity-temperature characteristic, and the relative dielectric constant by further containing an oxide of Si (Sample Nos. 40 to 43). In addition, when the content of the oxide of Si was excessively large (Sample No. 44), it was confirmed that the relative dielectric constant deteriorated.

From Table 3, it was confirmed that the relative dielectric constant can be improved while maintaining the AC breakdown voltage, the capacity-temperature characteristic, and the dielectric loss by further containing an oxide of Al (Sample Nos. 45 to 47). In addition, when the content of the oxide of Al was excessively large (Sample No. 48), it was confirmed that the dielectric loss deteriorated.

From Table 3, it was confirmed that the relative dielectric constant can be improved while maintaining the AC breakdown voltage, the capacity-temperature characteristic, and the dielectric loss by further containing an oxide of Ga (Sample Nos. 49 and 50). In addition, when the content of the oxide of Ga was excessively large (Sample No. 51), it was confirmed that the dielectric loss deteriorated.

(Example 4)

Zn ₂ SiO ₄ powder as a composite oxide material of Zn and Si, BaZnSiO ₄ powder as a composite oxide material of Zn and Ba and Si, ZnAl ₂ O ₄ as a composite oxide raw material of Zn and Al, And ZnGa ₂ O ₄ powder as a composite oxide raw material of Zn and Ga were prepared respectively and Zn ₂ SiO ₄ powder, BaZnSiO ₄ powder, ZnAl ₂ O ₄ powder and ZnO ₂ O ₄ powder were mixed together with Nb ₂ O ₅ powder for pre- , Or ZnGa ₂ O ₄ powder were each weighed and added so as to have the compositions shown in Table 4, and subjected to wet pulverization, to obtain samples of ceramic capacitors (Sample Nos. 60 to 79) in the same manner as in Example 1.

The composition of the obtained sintered body was confirmed to correspond to the composition shown in Table 4 by the same method as in Example 1. [ The relative dielectric constant, dielectric loss, AC breakdown field and capacity-temperature characteristics of each of the obtained capacitor samples were evaluated in the same manner as in Example 1, respectively. The results are shown in Table 4.

From Table 4, it can be seen from Table 4 that even when a composite oxide of Zn and Si, a complex oxide of Zn, Ba and Si, a complex oxide of Zn and Al, or a composite oxide of Zn and Ga is contained instead of Zn oxide, It was confirmed that a dielectric ceramic composition exhibiting a high AC breakdown voltage can be obtained while maintaining good dielectric constant, dielectric loss and capacity-temperature characteristics in the same manner as in the case of containing an oxide (Samples 22 to 27).

On the other hand, when the content of the complex oxide of Zn and Si, the complex oxide of Zn, Ba and Si, the complex oxide of Zn and Al, and the complex oxide of Zn and Ga is excessively large (Sample Nos. 63, 64, 69, 74 and 79 ), It was confirmed that the relative dielectric constant deteriorates.

(Example 5)

(Zn ₂ SiO ₄ powder), a composite oxide of Zn and Ba and Si (BaZnSiO ₄ powder), a composite oxide of Zn and Al (ZnAl ₂ O ₄ powder), a composite oxide of Zn and Si ) Or a composite oxide of Zn and Ga (ZnGa ₂ O ₄ powder) was used in place of the composite oxide (ZnGa ₂ O ₄ powder), respectively, to obtain a sample of a ceramic capacitor. .

As a result, even when a complex oxide of Zn and Si, a complex oxide of Zn and Ba and Si, a complex oxide of Zn and Al, and a complex oxide of Zn and Ga are contained in place of the oxide of Zn, Y " and the oxide content of Nb is the same as that in the case of containing an oxide of Zn (Samples 2 to 8, 14 to 17 in Table 1, and Samples 30 to 34 in Table 2) It was confirmed that the relative dielectric constant and the dielectric loss can be improved while maintaining the temperature characteristics.

2 … Ceramic Capacitors
4 … Protective resin
Six, eight ... Lead terminal
10 ... Dielectric layer
12, 14 ... Terminal electrode

Claims (4)

As a dielectric ceramic composition containing a compound represented _{by the} composition formula Ba _x (Ti _1-y Sn _y ) O ₃ and an oxide of Zn,
X in the composition formula is 0.970 to 0.996, y is 0.050 to 0.130,
Wherein the Zn oxide content is 1.5 to 8.0 parts by weight in terms of ZnO based on 100 parts by weight of the compound. The method according to claim 1,
Said dielectric ceramic composition further contains an oxide of Nb, the Nb content of the oxide is less than 0.6 parts by weight in terms of Nb ₂ O _5, based on 100 parts by weight of the compound the dielectric ceramic composition. 3. The method of claim 2,
Wherein the dielectric ceramic composition further contains an oxide of Si and the oxide content of Si is 2.0 parts by weight or less in terms of SiO _{2 based} on 100 parts by weight of the compound. An electronic part having a dielectric layer composed of the dielectric ceramic composition according to any one of claims 1 to 3.

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