JPH01267906A - Dielectric porcelain compound - Google Patents

Abstract

PURPOSE:To obtain a dielectric porcelain compound of high quality characterized by high level of dielectric constant, insulation resistance, and dielectric breakdown voltage by adding 0.1 to 10.0 weight part of Nb2O5 as a subcomponent to a compound which is primarily composed of SrO, CaO, TiO2 and ZrO. CONSTITUTION:In a compound whose primary components fall in the region of mole ratio in which x, y, z in an expression I are encircled by (a) (x=0.27, y=0.21, z=0.52), (b) (x=0.31, y=0.20, z=0.49), (c) (x=0.33, y=0.16, z=0.51), (d) (x=0.29, y=0.17, z=0.54) respectively, 0.1 to 10.0 weight part of Nb2O5 is contained as a subcomponent. These materials are mixed together for example in a wet process and after drying, they are Calcined for 2hours at 1100degrees centigrade. After being ground into powder and then molded the material is put in a mortar that is made of high purity alumina with ZrO2 powder spread on the bottom and then is calcined for 2hours at 1380degrees Centigrade, thus a dielectric porcelain being obtained. Thereby a dielectric porcelain compound of high quality which is characterized by high level of dielectric constant, insulation resistance and dielectric breakdown voltage and by a small coefficient of temperature can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to dielectric porcelain that has a high dielectric constant, insulation resistance, and breakdown voltage, has an excellent quality Q, has a small temperature coefficient, and is not easily affected by firing temperature fluctuations. The present invention relates to a composition.

BACKGROUND OF THE INVENTION The following systems have been known as dielectric ceramic compositions.

La20. -2TiO2-CaTiO, -2Mg0-T
ie2 system Tie2-BaTiO, -Bi20. -La2
05 series BaTi05 series 5rTiO, series CaTi0. System 5rTiO5-CaTi0. System MgTi0. System 5rTiO, -CaTi0. The problem that the -Nb2O5-based invention seeks to solve, however, is that one of these compositions has a high dielectric constant.

It is impossible to satisfy all of the requirements, such as a small temperature coefficient, excellent quality, and low sensitivity to firing temperature fluctuations.

Furthermore, a capacitor containing Bi□03 has the problem that Pd cannot be used as an internal electrode of a multilayer ceramic capacitor.

The present invention has high dielectric constant, insulation resistance, and breakdown voltage, excellent quality, and temperature coefficient? The object of the present invention is to obtain a dielectric ceramic composition that is small and hardly affected by fluctuations in firing temperature.

Means for Solving the Problems In order to solve this problem, the present invention provides
), where x+7+z==1. o.

00o1≦m≦o, 20 ” + 3' * z is each point a, b, c,
The composition is characterized in that it contains 0.1 to 10.0% by weight of Nb2O5 as a subcomponent to a composition whose main component is in the molar ratio range surrounded by d.

FIG. 1 is a triangular diagram showing the composition range of the main components of the composition according to the present invention, and the reason for limiting the composition range of the main components will be explained with reference to the diagram. That is, the temperature coefficient becomes too large on the (-) side in the M region and the C region, making it impractical. In addition, sintering becomes difficult in the B region and D region, and the dielectric constant and good quality Q.

Insulation resistance decreases.

Figures 2 and 3 are graphs showing the effect of the ratio m of ZrO2 that replaces a part of Tie2 in the main component;
The reason for limiting the replacement range of □ will be explained with reference to the graph. First, by replacing a portion of Tie with ZrO, the insulation resistance is increased as shown in FIG.
In addition, as shown in Figure 3, it has the effect of reducing temperature coefficient fluctuations due to the firing temperature, and if the substitution rate l is less than 0.01, there is no substitution effect, while if it exceeds 0.2, sintering becomes difficult. , dielectric constant, quality Q, and insulation resistance decrease.

FIG. 4 is a graph showing the effect of containing Nb2O5 as a subcomponent added outside to the main component.
, 05 will be explained with reference to the graph. First, as shown in Fig. 4, the inclusion of Nb2O5 has the effect of increasing the breakdown voltage, but if the content is less than 0.1% by weight with respect to the main component, there is no effect of the inclusion; If it exceeds 0.0% by weight, the goodness Q will decrease and the temperature coefficient will increase toward the (-) side, making it impractical.

The present invention further provides manganese, chromium, iron, and nickel for the composition consisting of the above main components and subcomponents.

At least one selected from the group consisting of cobalt and silicon oxides is MnO□.

The composition contains 0.06 to 1.00% by weight of Or, O, FeO, NiO, Coo, and Sin. These additives have the effect of improving the sinterability of porcelain, but if the amount added is less than 0.06% by weight, there is no addition effect, and if it exceeds 1,00% by weight, the dielectric constant will decrease. Become.

Effect The dielectric ceramic composition of the present invention has a high dielectric constant, insulation resistance, and dielectric breakdown voltage, has an excellent quality Q, has a small temperature coefficient, and is hardly affected by sintering temperature fluctuations. can be obtained.

Example The present invention will be explained below using specific examples.

(Example 1) Chemically highly purified 5rCO, CaCO3 was used as the starting material.
゜Tie2. ZrO, and Wb20. Weigh the powder so that it has the composition shown in Table 1 below, place it in a rubber-lined ball mill equipped with an agate ball together with pure water, and
Wet mixing was carried out for 0 hours. After dehydrating and drying this mixture, 11
Temporary firing was performed at 00°C for 2 hours. After coarse pulverization, the mixture was again placed in a rubber-lined ball mill equipped with agate balls together with pure water, and wet pulverized for 20 hours. After the pulverized product was dehydrated and dried, 9% by weight of an aqueous polyvinyl alcohol solution with a concentration of 5% was added to the powder as a binder to make it homogeneous, and the powder was sized through a 32-mesh sieve. Next, the sized powder was molded using a mold and a hydraulic press at a pressure of 1 to
The molded product was molded to a diameter of 15 mm, thickness of 4 g, and then placed in a high-purity alumina sagger lined with ZrO2 powder, and heated in air at the temperature shown in Table 1 below.
Firing was performed for a period of time to obtain dielectric porcelain having the composition shown in Table 1 below.

The electrical properties of these samples were determined by baking silver electrodes on both sides of the samples, and measuring the dielectric constant, goodness Q, and temperature coefficient using a digital LCR meter model 42 manufactured by Yokogawa-Heuret Paracard Co., Ltd.
Using 76A, measurement temperature: 2°C2 measurement voltage: 1. o
Vrms was determined by measurement at a measurement frequency of 1 MHz.

The temperature coefficient was determined from the following formula using the capacitance value at 20°C as a reference.

Temperature coefficient = (Css℃−C2o℃)/(020℃×65
)X 10 (1) pm/℃) Insulation resistance was measured using HR meter model 4329 manufactured by Yokogawa-Heuret Paracard Co., Ltd., and the measurement voltage was C,so V, and the measurement time was 1 minute. I asked for it. Furthermore, the dielectric breakdown voltage was determined by using a type 13 high voltage power supply PH536 manufactured by Kikusui Electronics Co., Ltd., and a boosting speed of 50 V.
/ 3510 was divided by the element thickness to obtain the dielectric breakdown voltage value per unit length. These test conditions and results are also shown in Table 1.

(Left below) (Example 2) Starting materials include chemically highly purified SrCO3, CaC0,
lTi02, ZrO2, Wb 205. MnO2,C
r 203jeo, Nip, Co.

and 5102 powder were weighed to have the compositions shown in Table 2 below, and thereafter treated in the same manner as in Example 1 above to obtain dielectric ceramics having the compositions shown in Table 2.

The test methods for these samples were the same as in Example 1, and the test conditions and results are also shown in Table 2.

(Left below) Effects of the Invention As described above, according to the present invention, the dielectric constant, insulation resistance and dielectric breakdown voltage are high, the quality Q is excellent, the temperature coefficient is small, and it is not affected by firing temperature fluctuations. In addition, the firing temperature can be lowered by adding oxides of manganese, chromium, iron, nickel, iron, and arsenic.

Furthermore, since the obtained dielectric ceramic has a high dielectric constant, the element body can be made extremely small, and it is effective for miniaturizing circuits. Suitable for uses such as 0

[Brief explanation of the drawing]

Figure 1 shows 1% by weight Nb2O as a subcomponent related to the present invention.
Fig. 2 is a triangular diagram showing the composition range of the main component containing 5, which contains 1% by weight Nb2O5 as a subcomponent related to the present invention, and the general formula of the main component is expressed as 0.30, Y20.19, m=0.5
1, and the graph showing the change in characteristics when the substitution ratio m of Zr02 is changed up to 0.26. Figure 3 shows a graph containing 1% by weight Nb2O5 as a subcomponent related to the present invention, and a general formula of the main component. When expressed as % formula %)), x=0.30, 7==0.19, z=0
．． 51, the substitution ratio m of ZrO□ was changed to 0.26, and the calcination temperature was further changed from 1340 to 1380° Ct. Figure 4 shows the changes in temperature characteristics of the main components according to the present invention. General formula % formula %): ] When expressed as ! =0.30, 7=0.19, m=0.51
, is a graph showing changes in characteristics when m=0.06 and the content of subcomponent Nb2o5 is changed up to 16% by weight. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure J component NtnOsllll for principal component: amount 2 content (T
iO2)fl-mXZPQ2)m
((7t02)I+-+++i'ZrOz)mノ! True partial pressure example; 9Nbt05 Zr (h during replacement m Figure 3 Z, 021 replacement m

Claims (2)

[Claims] (1) General formula xSrO-yCaO-z [(TiO_2)_(_1_-
_m)・(ZrO_2)_m], where x+y+z=1.00 0.01≦m≦0.20 x, y, and z are surrounded by the points a, b, c, and d shown below. A dielectric ceramic composition characterized in that it contains 0.1 to 10.0% by weight of Nb_2_O_5 as a subcomponent with respect to the composition having a molar ratio of 0.1 to 10.0% by weight as a main component. (2) At least one selected from the group consisting of oxides of manganese, chromium, iron, nickel, cobalt and silicon is added to the dielectric ceramic composition according to claim 1, respectively. , NiO. C
A dielectric ceramic composition characterized in that it contains 0.05 to 1.00% by weight in terms of oO and SiO_2.