JPH03165403A - Dielectric porcelain composition material - Google Patents

Abstract

PURPOSE:To obtain a high-performance dielectric porcelain by selecting composition ratios x, y, and z within the specific region in a composition range determined by three compounds of BaO, [(TiO2)1-m(SnO2)m)], and [Re1-nMen] (composition ratio m and n), and adding a prescribed sub-component. CONSTITUTION:Formulas of three compounds are as follows: x+y+z=1.00, 0.01<=m<=0.20, and 0.10<=C<=0.20, where Re is one or more kinds of rare earth elements selected from La, Pr, Nd, and Sm, and Me is one or more kinds of rare earth elements selected from rare earth elements except La, Pr, Nd, and Sm. Here two or more selected kinds, composed of Nb2O3, Ta2O3, and V2O3, of 0.001-0.010mol part in total are contained as a sub-component to a main component of 100 weight parts composed of a range of a mol ratio in which composition ratios x, y, and z are surrounded with each point (a), (b), (c), (d), (e), and (f). This increases a dielectric constant, insulation resistance, and dielectric breakdown voltage, sharply improves good Q, and reduce an electrostatic capacity temperature coefficient to permit miniaturization, large capacity, and characteristic improvement of products.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention has high dielectric constant, insulation resistance, and dielectric breakdown voltage, greatly improves the quality Q, has a small capacitance quality factor, and has a low density. The present invention relates to a dielectric ceramic composition capable of producing large dielectric ceramics.

BACKGROUND OF THE INVENTION Conventionally, the following systems have been known as dielectric ceramic compositions that have high dielectric constant and insulation resistance, excellent quality Q, and small temperature coefficient of capacitance.

・Ba0-Ti 02-Nd2O3 system ・Ba0-Ti
Problems to be solved by the O2-3m203-based invention However, these compositions are, for example, 0.098aO-0,557i02-〇, 36Nd03
When a disk-shaped ceramic capacitor is manufactured using a dielectric material with a composition ratio of 72, the average value of insulation resistance: 8.0 x 1012 Ω, and the average value of dielectric breakdown strength: 30 kv/
mm, which is not a satisfactory value.

The density of this dielectric ceramic is 5.6 g/cJ, but it is generally used for glue flow soldering, especially paper reflow soldering, of multilayer ceramic capacitors with a length (L) of 3.2 mm and a width (W) of 1.6 mm or less. In order to prevent this problem, the density of the dielectric porcelain must be increased to prevent chipping (also known as tombstone phenomenon or tombstone phenomenon). was there.

Means to solve problems In order to solve these problems, the present invention develops the general formula %formula%) (However, X+Y+Z=1.OO.

0.01≦m≦0.20, 0.01≦C≦0.20゜x
BaO-y [(TiO2) (One or more rare earth elements selected from 1-m. Me is one or more rare earth elements selected from rare earth elements excluding La, Pr, Nd, and Sm.), x, y, and z are Each point a, b, c, d shown below.

Nb2O5, Ta205゜v as subcomponents to 100 parts by weight of the main component consisting of the molar ratio range enclosed by e and f.
Two or more types selected from 2o5 with a total of 0.001 to 0.
Figure 1 is a ternary diagram showing the composition range of the main components of the composition according to the present invention, and the reasons for limiting the composition and range of the main components are shown in Figure 1. This will be explained with reference to. That is, sintering is extremely difficult in the region. Furthermore, in region B, the quality Q decreases, making it impractical. Furthermore, in regions C and D, the capacitance temperature coefficient becomes too large on the negative side, making it impractical. In region E, the temperature coefficient of capacitance shifts to a positive direction, but the dielectric constant is too small to be practical. Furthermore, by selecting Re from La, Pr, Nd, and Sm, it is possible to shift the capacitance temperature coefficient in the positive direction without significantly lowering the dielectric constant in the order of La, Pr, Nd, and Sm. , La, Pr, Nd, and Sm, or a combination thereof, the capacitance temperature coefficient can be adjusted. Furthermore, a part of one or more rare earth elements selected from La, Pr, Nd, and Sm is La, Pr.

Substitution with one or more rare earth elements selected from rare earth elements other than Nd and Sm has the effect of significantly improving the quality Q, but if the amount of substitution is less than 0.01, there is no substitution effect. On the other hand, if it exceeds 0.20, the dielectric constant decreases and becomes impractical.

In addition, by replacing TlO2 with 5n02, it has the effect of increasing the density of dielectric ceramic without significantly changing the values of dielectric constant, goodness Q, temperature coefficient of capacitance, insulation resistance, and dielectric breakdown strength. However, the substitution rate m′b<o
, less than 0.01, there is no substitution effect; on the other hand, if it exceeds 0.20, the dielectric constant and goodness Q decrease, and the temperature coefficient of capacitance becomes too large on the negative side, making it impractical.

In addition, with respect to the main component, the subcomponent Nb2O5°Ta205.
Containing V2O5 has the effect of improving insulation resistance and dielectric breakdown strength, but Nb2O5, Ta2
05. If the total content of V2O5 is less than 0.001 parts by mole based on 100 parts by weight of the main component, the dielectric breakdown strength is not so high and it is excluded from the scope of the present invention. On the other hand, Nb
205Ta205. If the total content of V2O5 exceeds 0.010 mole part based on the main components, the quality Q and insulation resistance will decrease, and the temperature coefficient of capacitance will become large on the negative side, making it impractical. Also, Nb2O5゜T a 20
5, V205, Nb2O6, Ta205. Compared to those containing one selected from V2O5, the dielectric constant, insulation resistance, and dielectric breakdown voltage are higher, the quality Q is excellent, and the temperature coefficient of capacitance is smaller.

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

(Example 1) The starting material was B a C03°TiO of relatively high purity.
2,5n02. La2O3, Pr60Ce○2. Gd2
O3, D V2O3, Nd2O3゜Sm2Ch, Nb2
O5, Ta205 and V2o5 powders were weighed to have the composition ratio shown in Table 1 below, placed in a rubber-lined ball mill equipped with an agate ball together with pure water, wet mixed, and then dehydrated and dried. This dry powder was placed in a high alumina crucible and calcined in air at 1100°C for 2 hours.

This calcined powder was put into a rubber-lined ball mill equipped with agate balls together with pure water, wet-pulverized, and then dehydrated and dried. After adding an organic binder to this pulverized powder and making it homogeneous, it was sized through a 32-mesh sieve, and molded into a diameter of 15 mm and a thickness of 0.4 mm using a mold and a hydraulic press at a molding pressure of 1 ton/cJ. did. Next, this molded disk was placed in an alumina pod covered with zirconia powder and fired in air at the temperature shown in Table 1 below for 2 hours to obtain dielectric porcelain having the composition ratio shown in Table 1. Ta.

The thickness, diameter, and weight of the dielectric ceramic disc thus obtained were measured, and one weight was divided by the volume calculated from the thickness and diameter to determine the density of the dielectric ceramic.

In addition, the samples for measuring dielectric constant, quality Q, and capacitance temperature coefficient are made of dielectric ceramic disks with silver electrodes baked on the entire surface of both sides, and the samples for measuring insulation resistance and dielectric breakdown strength are made of dielectric ceramic disks. A 1 mm wide part without a silver electrode was provided inside the outer periphery, and a silver electrode was baked onto it.

Then, the dielectric constant, goodness Q, and capacitance temperature coefficient are YH
Using a digital LCR meter model 4275A manufactured by Company P, the measurement temperature was 20°C, 71111 constant voltage 1, OV
r m s , measurement frequency LM) was determined by measurement at IZ. The capacitance temperature coefficient was determined by measuring capacitance at 20° C. and 85° C. using the following formula.

TC-(C-Co)/CoX l/65X 106TC
: Temperature coefficient of capacitance (ppm/'C) CO・Capacitance at 20° C. (pF) C: Capacitance at 85° C. (pF) Further, the dielectric constant was determined from the following formula.

K = 143.8 Co , was determined by measurement using HR meter model 4329A manufactured by YHP Co., Ltd. at a measurement voltage of 50V, D, C, and a measurement time of 1 minute.

The dielectric breakdown strength is determined by using the Kikusui Electronics High Voltage Power Supply P) (Type 13 for 335, placing the sample in Ginocon oil, and calculating the dielectric breakdown voltage with a boost rate of 50 V/see. The dielectric breakdown strength was expressed as dielectric breakdown strength per 1 mm.

The test conditions are also shown in Table 1, and the test results are shown in Table 2 below.
Shown in the table.

(Margins below) In addition, in the method for producing dielectric ceramic in the example, Ba
CO3, TiO2, Sn○2. La2O3゜P r
s O+ + , N d 203 , S m 20
3. CeO2゜Gd2O3, Dy2O3, Nb2O5,
Although Ta205, V, and Os were used, the method is not limited to this method, and so as to obtain a desired composition ratio.
Compounds such as BaTiO3, carbonates, hydroxides, etc. can be converted to BaO by heating in air.

TiO2,5n02. La2O3,Pr(HONdx0
3. Sm2O3, CeO2, Gd2O3゜Dy2O3,
Even if compounds such as Nb2O5, Ta205 and V2O5 are used, properties comparable to those of the examples can be obtained.

Further, even if the main component is calcined in advance and the subcomponents are added, properties comparable to those of the examples can be obtained.

In addition to the basic composition mentioned above, SiO2MnO2, F
Salts, oxides, etc. that are generally considered to be fluxes, such as e2O3 and ZnO, can also be added to the extent that they do not impair the properties.

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 greatly improved, and the temperature coefficient of capacitance is small, so that the product can be made smaller and have a larger capacity. It is possible to improve emotions and characteristics. In addition, since it is a dielectric porcelain with a higher density, when small surface-mount chip components are made with this composition, it is possible to obtain products with high mounting performance, such as improving chip standing during reflow soldering. be.

[Brief explanation of the drawing]

FIG. 1 is a ternary diagram illustrating the composition range of the main components of the composition according to the present invention.

Claims (1)

[Claims] General formula xBaO-y[(TiO_2)_(_1_-_m_)(
SnO_2)_m]-z(Re_(_1_-_n_)M
e_n) When expressed as O_3_/_2 (however, x+y+
z=1.00, 0.01≦m≦0.20, 0.01≦C
≦0.20, Re is one or more rare earth elements selected from La, Pr, Nd, and Sm. Me is La, Pr, Nd, S
One or more rare earth elements selected from rare earth elements excluding m. ), Nb_2O_5, Ta_2O_5, V as subcomponents to 100 parts by weight of the main component consisting of a range of molar ratios where x, y, z are surrounded by each point a, b, c, d, e, f shown below.
Two or more types selected from _2O_5 total of 0.001~
A dielectric ceramic composition characterized in that it contains 0.010 mole part.