JPH03263706A - Dielectric porcelain composition - Google Patents

Abstract

PURPOSE:To obtain a dielectric porcelain composition with a high dielectric constant, high insulation resistance, high dielectric breakdown voltage, excellent quality Q, and a small static capacity temperature coefficient by specifying the mole rations of elements of a composition made of oxides of Ba, Ca, Ti, Zr and rare earth elements. CONSTITUTION:A dielectric porcelain composition is expressed by a general formula x [(BaO)(1-m)(CaO)m]-y[(TiO2)(1-n)(ZrO2)n]-ZReO3/2, where x+y+z=1.00, 0.01<=m<=0.30, 0.001<=n<=0.200, and Re is one or more kinds of rare earth elements selected among La, Pr, Nd, and Sm. (x), (y), and (z) are within the range of mole ratios surrounded by points (a), (b), (c), (d), (e), and (f) in the figure. When Re is selected among La, Pr, Nd, and Sm, the static capacity temperature coefficient can be moved in the plus direction in the order of La, Pr, Nd, and Sm without largely reducing the dielectric constant, and the static capacity temperature coefficient can be adjusted by one kind or the combination of La, Pr, Nd, and Sm.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a dielectric ceramic composition that has a high dielectric constant, high insulation resistance, high dielectric breakdown voltage, excellent Q quality, and low temperature coefficient of capacitance.

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.

・BaOTi0z Nd'tOs system・[laOTi
However, these compositions, for example, 0.09BaOO, 5
When a disk-shaped ceramic capacitor is manufactured using a dielectric material with a composition ratio of 6TiOz 0.35NdOzzx, the dielectric constant is 267, the goodness Q: 3000, the capacitance temperature coefficient: N40ppm/''c, and the insulation resistance: 8
．． 0XlO''Ω, and the crystal grain size is large, 1 to 5 μm, so the porosity in the element body increases and the electric field strength applied to each crystal grain increases, resulting in a dielectric breakdown strength of 30 kv/m. , not a satisfactory value.

Means for Solving the Problems In order to solve these problems, the present invention provides a general formula % (ZrOz)al zRe037g when expressed as (
However, X + y + z-1-rn 0.30, O, 0
01$n≦0.200, Re is La, Pr, Nd
, Swa - species or more of rare earth elements selected from Swa.

), x, y-z are shown in Table 1'□ Each point a, b, c, d
, e, and ff.

FIG. 1 is a binary diagram showing the composition range of the four precepts of the composition according to the present invention, and the principle of determining the composition range of the main components will be explained with reference to FIG. Zuna Saitsuchi,
Sintering is marked and difficult in the hole region. In the j, ta, and 3 areas, the quality Q decreases and becomes impractical. Furthermore, C,
In region D, the temperature coefficient of the electrostatic field becomes too large on the negative side, making it impractical.

In the R region, the electrostatic field temperature coefficient shifts to a positive force direction, but the dielectric constant is too small to be practical. Also, R
eZLa, Pr, Ni1. By selecting from Sm, it is possible to shift the capacitance temperature coefficient toward brass J without significantly lowering the class C permittivity of La, Pr, Nd, S-41, a, Pr, Nd
, the electrostatic field temperature coefficient can be adjusted by one type of axis or a combination thereof.

In addition, by replacing BaO with CaO, the degree of goodness Ω can be reduced to 1iil, 1iil, hsaou, insulation, without significantly changing the dielectric constant, static 1, capacity JHX degree coefficient, and dielectric breakdown strength. Although the effect of increasing the resistance IA is good, if the tolerance n1 is less than 0.01, there is no substitution effect;
．． If it exceeds 30, the degree of goodness Ω and the insulation resistance will decrease, and the temperature coefficient of the 4 electrostatic field M will also become too large on the negative side, making it impractical.

Furthermore, by replacing Tie with ZrOz, the dielectric constant, goodness Q, capacitance temperature coefficient, and insulation resistance tJ'14
It has the effect of reducing crystal grain size and increasing dielectric breakdown strength without significantly changing the value of
Replacement wheel Less than 7' There is no conversion effect, and if it exceeds 0.200, the dielectric constant, length Ω, and insulation resistance will decrease.

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

(Example 1) First, the starting material is chemically high-purity BJI COs.
rCaCOs+DingLog, ZrO*+ La=03
．． PF*0+t+ Ndz03, S, and m1O1 powders were pressed into 11 ratios as shown in Table 1, and placed in pure water εε in a rubber-lined pole fountain equipped with an agate ball, and wet mixed. After that, it was dehydrated and dried. Put this dry powder into a high-aluminum J/quality crucible C, and use an air cloth to
Calcined at 0°C for 2 hours.

Calcined powder, $:, i:, Agate poles were placed in a brazed rubber-lined bowl with pure water, wet-pulverized, and then dehydrated and dried. 0) Add an organic binder to the crushed fruit powder to make χJW, and then pass it through a sieve to Vt1 (,, acid form pressure l t using a metal and oily breather.
on/eJ-diameter 15mm, PI: diameter 0.4m
Mold into m. Next, the formed disk was placed in an alumina pod lined with silk: -7 powder, and the σ below ゛ζ was placed in the air.
] Baking for 2 hours at the temperature shown in Table 1J2, Not shown in Table 1L
A dielectric porcelain of 1 prestige was obtained.

20) The diameter of the electric field test disk obtained in the above manner was measured, and the sample for measuring the dielectric constant, goodness Q, and temperature coefficient of Ill charge was dielectric magnetic! [iiP] Burn a silver electrode over the entire opening of the plate, and the sample for measuring insulation resistance and absolute U breakdown strength should be placed 1m inward from the outer periphery of the dielectric porcelain disk! ! The silver electrode was burnt (4 times) by setting the part of the electrode (named).
Dielectric constant, degree of goodness Ω, electrostatic field temperature coefficient center, side/hysteresis
L/Tuto Bunker 1' wholesale digital i,, cr,
'Using meter model 4275 Yakan.

It was determined by measurement at a measurement temperature of 20''C5, a measurement voltage of 1, OVrms, and a measurement frequency of IMHz.The capacitance temperature coefficient was determined by measuring the capacitance at 20°C and 85°C and using the following formula. .

TC= (C-Co)/CoX1/65X10″TC:
Temperature coefficient of capacitance (ρpm/''C) Co: Capacitance at 2Q°C (pF) C: Capacitance at 85°C (pF) The dielectric constant was determined from the following formula.

K = 143.8XCoXt/D” K: Dielectric constant Co: Capacitance at 20°C (pP) D: Diameter of dielectric porcelain (III) t: Thickness of dielectric porcelain (Kaku) Furthermore, the insulation resistance is It was determined by measurements using an HR meter model 4329 A made by Horizontal/Hyulet/Paracard ■ at a measurement voltage of 50V, D, C, and a measurement time of 1 minute.

The dielectric breakdown strength was determined by using a type 13 high voltage power supply PH535 manufactured by Kikusui Electronics Co., Ltd., placing the sample in silicone oil, and dividing the dielectric breakdown voltage determined by a voltage increase rate of 50 V/see by the dielectric thickness. , the dielectric breakdown strength per 1 yen.

Further, the crystal grain size was determined by optical microscope observation at a magnification of 400.

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

(Left below) Table 1〉〈Table 2〉 In addition, in the method for producing dielectric porcelain in the example, Ba
COx, CaC0! + Tilt, Zr01. L
at, 1Pr*O+++NdO0. and 5mg02 were used, but the method is not limited to this method, and by heating in air a compound such as BaTi0), carbonate, hydroxide, etc., to obtain the desired m-acid ratio.
ad, Cab, Ti01ZrOz+ LazOz+
Characteristics comparable to those of the examples can be obtained even by using the compounds Pr1O+++ Nd*Os and Ss@02.

In addition to the basic composition mentioned above, SiO□MnO□Pe
Salts, oxides, etc., which are generally considered to be fluxes, such as gOz and ZnO, can also be added to the extent that the properties are not impaired.

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, and the temperature coefficient of capacitance is small, so that the product can be made smaller, have a larger capacity, and have better characteristics. Improvement is possible.

[Brief explanation of drawings]

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

Claims (1)

[Claims] General formula x [(BaO)_(_1_-_m_)(CaO)_m]
−y[(TiO_2)_(_1_-_n_)(ZrO_
2)_n]-zReO_3_/_2 (where x+y+z=1.00, 0.01≦m≦0.30, 0
．． 001≦n≦0.200, Re is La, Pr, Nd,
One or more rare earth elements selected from Sm. ), x, y,
A dielectric ceramic composition characterized in that z consists of a molar ratio range surrounded by points a, b, c, d, e, and f shown below.