JPH03216911A - dielectric porcelain composition - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a dielectric ceramic composition that has 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 a high dielectric constant and insulation resistance, an excellent Q quality, and a small temperature coefficient of capacitance.・BaO TiOz
NdzOs type/BaO Tilt Sa
However, these compositions, for example, 0.09BaO -0
．． When a disk-shaped ceramic capacitor is manufactured using a dielectric material having a composition ratio of 56TiOz and 0.35NdOszg, the dielectric constant: 67 and the capacitance temperature coefficient: N40.
GIPII /°C, quality Q: 3000, insulation resistance: 8. OX10”Ω, dielectric breakdown strength = 30κV/
The price is not satisfactory. Means for Solving the Problems In order to solve these problems, the present invention provides the general x[(B
aO) 11-a) (MgO) al yTi
When expressed as ot lReo3yx (however, x+y+
z=1.00, 0<m≦0.50, ReLtLa, P
r+ One or more rare earth elements selected from Nd and Ss. ), x, y, z are the following points a, b, c, d, e
, f is proposed. FIG. 1 is a ternary 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 FIG. In other words, sintering is extremely difficult in the AfII region. In addition, in the BsJl range, the quality Q decreases, making it impractical. Furthermore, C, DiJf
In the range, the temperature coefficient of capacitance becomes too large on the negative side, making it impractical. In the EfiI region, the temperature coefficient of capacitance shifts to a positive direction, but the dielectric constant is too small to be practical. Also, Re is La, Pr. Nd+
By selecting from Sw, La, Pr, Nd,
It is possible to shift the capacitance temperature coefficient in the positive direction without significantly lowering the dielectric constant in the order of S1, and La
, Pr, Nd+ SIl, or a combination thereof, the temperature coefficient of capacitance can be adjusted. In addition, by replacing BaO with MgO, the dielectric constant,
without significantly changing the quality Q and dielectric breakdown strength values.
It has the effect of shifting the capacitance temperature coefficient in the positive direction and increasing the insulation resistance, but the substitution rate m is 0.01.
If it is less than 0.50, there will be no substitution effect, and if it exceeds 0.50, the dielectric constant will decrease and become impractical. EXAMPLES The present invention will be explained below using specific examples. (Example 1) Chemically high-purity BaCO, MgO are used as starting materials.
, TIOI, LatOs+ PrJ+++ NdxO
S and Sag (h powders were weighed to have the composition ratio shown in Table 1 below, put into a rubber-lined ball mill equipped with agate balls together with pure water, wet mixed, and then dehydrated and dried. This dry powder was It was placed in a high alumina crucible and calcined in air at 1100°C for 2 hours.The calcined powder was placed in a rubber-lined ball mill with agate balls together with pure water, wet-pulverized, and then dehydrated and dried. An organic binder was added to this pulverized powder to make it homogeneous, and then the powder was sized through a 32 mesh sieve, and molded into a diameter of 15 cm and a thickness of 0.4 mm using a mold and a hydraulic press at a molding pressure of 1 ton/cj. Next, this molded disk was placed in an alumina pod covered with zirconia powder, and the following first step was carried out in the air.
It was fired for 2 hours at the temperature shown in the table to obtain dielectric porcelain having the composition ratio shown in Table 1. The thickness and diameter of the dielectric porcelain disk thus obtained were measured, and the samples for measuring the dielectric constant, goodness Q, and capacitance temperature coefficient were prepared using silver electrodes on both sides of the dielectric porcelain disk. The samples for baking, insulation resistance, and dielectric breakdown strength measurements were made by setting a part with no silver electrode on the inside of the outer periphery of a dielectric porcelain disk and baking the silver electrode. And, the dielectric constant, goodness Q, and capacitance temperature coefficient are Yokogawa/Heuresoto/Baccard■
Using a digital LCR meter model 4275 A made by Manufacturer, the measurement temperature was 20°C and the measurement voltage was 1. OVrms, determined from measurements at a measurement frequency of 1MHz. The capacitance temperature coefficient was determined by measuring capacitance at 20°C and 85°C using the following formula. TC=(C-Co)/CoXi/65XlO”TC:
Capacitance temperature coefficient (ppm/”C) Co: Capacitance at 20°C (pF) C: Capacitance at 85°C (pF
) Also, the dielectric constant was calculated from the following formula. K= 143.8x C o X t / D”K:
Dielectric constant Co: Capacitance at 20'C (pP) D: Diameter of dielectric porcelain (1) L: Thickness of dielectric porcelain Using meter model 4329A, the measurement voltage was 50V. [l. C. , determined from measurements with a measurement time of 1 minute. The dielectric breakdown strength was determined by using a high-voltage power supply PH535K-3 manufactured by Kikusui Electronics Corporation, placing the sample in silicone oil, and dividing the dielectric breakdown voltage determined by the voltage increase rate of 5 QV/see by the dielectric thickness. It was taken as the dielectric breakdown strength per unit. The test conditions are also shown in Table 1, and the test results are shown in Table 2 below.
It is shown in the table. In the following margin, in the method for producing dielectric ceramic in the example, Ba
CO1+ MgO, TiOg+ LaxOs+ Pr
*0+++ Although Nd, o, and Sexes were used, the method is not limited to this method. Compounds such as Ba↑10, or carbonates, hydroxides, etc. in the air are used to obtain the desired composition ratio. Bad, M
gO+riot, LagOs+Pr. O+++
NToOs and Sm. Even if a compound of 01 is used, properties comparable to those of the example can be obtained. In addition to the above-mentioned basic composition, SiOgn MnOg, 'eto
3+ Salts and oxides, such as ZnO, which are generally considered Franks, 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 excellent, and the temperature coefficient of capacitance is small. Improvement is possible.

[Brief explanation of drawings]

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

Claims (1)

[Claims] General formula x [(BaO)_(_1_-_m_)(MgO)_m]
-yTiO_2-zReO_3_/_2 (where x+y+z=1.00, 0.01<m≦0.50
, Re is one or more rare earth elements selected from La, Pr, Nd, and Sm. ), x, y, z are each point a, b represented below
, c, d, e, and f.