JPH04167309A - Dielectric porcelain compound - Google Patents

Abstract

PURPOSE:To heighten dielectric constant, insulation resistance and dielectric breakdown voltage as well as improving Q remarkably, make electrostatic capacity temperature coefficient small, make capacity large and improve characteristics by using vanadium oxide as a sub-gradient as well as one or more rare earth element as a main gradient. CONSTITUTION:A composition is constituted of 0.005-1.00 parts by weight of vanadium oxide (V2O5) as a sub-gradient as well as 100 parts by weight of main gradients (x, y, z) in the rang of mol ratios surrounded by respective points (a) to (f) as shown in the attached table, when expressed by a general formula: x[(BaO)1-h (SrO)h]-yTiO2-z(Re1-tMet)O3/2, where(x+y+z)=1.00, 00.1<=(h)<=0.30, 0.01<=(t)<=0.20, Re is one or more of rare earth element selected from La, Pr, Nd, Sm, and Me is one or more element selected except La, Pr, Nd, Sm. To produce porcelain by using the compound, firstly powder of which composition ratio is specified is measured and mixed with moisture, then dying same, and after an organic binder is added thereto baking is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a dielectric ceramic that has high dielectric constant, insulation resistance, and breakdown voltage, greatly improves Q, and has a small capacitance N temperature coefficient. The present invention relates to a body porcelain composition.

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

・BaOTiOz NdzOz system ・BaO-Tilt-5azos system Problems to be solved by the invention However, these compositions, for example, 0.09BaOO, 5
When a disk-shaped ceramic capacitor is made using a dielectric material with a composition ratio of 6TiOx 0.35N (rozz□), the dielectric constant: 67, the capacitance temperature coefficient: N40pp
■／'C,Q: 3000, insulation resistance: 8.0X1
01z! Q, dielectric breakdown strength = 30 ν/W, which is not a satisfactory value.

II! Means for Solving These Problems In order to solve these problems, the present invention provides that when expressed as the general formula % z (Re l+ -t+ Met) 0syx (where x+y+z-1,00,0,01≦
h≦0, 30.0.01≦t≦0.20, Re is La,
One or more rare earth elements selected from Pr, Nd+Ss; Me is one or more rare earth elements selected from rare earth elements other than La, Pr, Nd, and S■. ), X.

For 100 parts by weight of the main component, where y and z are in the molar ratio range surrounded by each point a, b, c, d, e, f shown below,
The present invention proposes a dielectric ceramic composition characterized in that it contains vanadium oxide as a subcomponent in an amount of 0.005 to 1.000 parts by weight in terms of v20°.

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. That is, sintering is extremely difficult in region A. Further, in the B region, the Q is lowered, 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.

In addition, by selecting Re from La, Pr, and Nd+ Sll, 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 and Nd+ Sv. Pr, N
The temperature coefficient of capacitance can be adjusted by one type of d, Sv+, or a combination thereof. Furthermore, La, P
One or more rare earth elements selected from r, Nd, 5g, L, a, Pr, Nd.

Substitution with one or more rare earth elements selected from rare earth elements other than S- has the effect of significantly improving Q, but if the substitution rate t is less than 0.01, there is no substitution effect; , 0.20, the dielectric constant decreases and becomes impractical. In addition, by replacing BaO with SrO, it has the effect of increasing the dielectric constant, Q, and dielectric breakdown strength without significantly changing the capacitance temperature coefficient and insulation resistance values, but the substitution rate is If it is less than 0.01, there will be no replacement effect, while if it is less than 0.30, the insulation resistance will decrease.
The capacitance temperature coefficient also increases to the negative side, making it impractical.

In addition, by including the subcomponent VzOs with respect to the main component, the insulation resistance, I! Although it has the effect of improving edge breaking strength, v20. If the content is less than 0.005 parts by weight with respect to 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, v2
0. If the content exceeds 1.000 parts by weight based on the main component, the insulation resistance will decrease and it will become impractical.

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

(Example 1) First, chemically highly purified V2O3°Laz was used as the starting material.
Oj+ PrhO+++ NdzOs, 5azOz,
CeO, GdgOs+DyzOz+ Ti0z+ 5
rC(h) and BaCO5 powder were weighed to have the composition ratio shown in Table 1 below, placed in a rubber-lined ball mill equipped with an agate pole together with pure water, wet mixed, and then dehydrated and dried. It was placed in a high alumina crucible and calcined in air at 1]00°C for 2 hours.The calcined powder was placed in a rubber-lined ball mill with an agate pole together with pure water, wet-pulverized, and dehydrated. After drying, an organic binder was added to this pulverized powder to make it homogeneous.
The particles are sized through a sieve with a mesh size of 32 mm, and are molded into a diameter of 15 mm using a mold and a hydraulic press at a molding pressure of 1 ton/cir.
It was molded to a thickness of 0.4 m. Next, the obtained molded disk was placed in an alumina pod covered with zirconia powder.
Firing was carried out in air for 2 hours at the temperature shown in Table 1 below to obtain dielectric porcelain having the composition ratio shown in Table 1.

The thickness, diameter, and weight of the dielectric ceramic disk obtained in this way were measured, and the sample for measuring the dielectric constant, Q, and capacitance temperature coefficient was measured using a dielectric material [silver electrodes were placed on both sides of the disk]. A sample for measuring insulation resistance and dielectric breakdown strength was prepared by providing a 1 m wide part without a silver electrode inside the outer periphery of a dielectric ceramic disk, and baking a silver electrode thereon. And, the dielectric constant, Q, and capacitance temperature coefficient are Yokogawa/Heuret/Paracard■
Using a digital LCR meter model 4275A made by
It was determined by measurement at a measurement temperature of 20°C, a measurement voltage of 1.0Vr+ns, and a measurement frequency of IMHz. The temperature coefficient of capacitance was determined by measuring capacitance at 20"C and 85C, and using the following formula.

T C= (C-Co)/CoX 1/65X
10'TC: Capacitance temperature coefficient (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 = 143.8X Co Further, the insulation resistance was determined by measurement using an HR meter model 4329A manufactured by Yokogawa Huuret Pancard ■ at a measurement voltage of 50V, D, C, and a measurement time of 1 minute.

And, the dielectric breakdown strength is high voltage electric f
A type 13 iPH335 was used, the sample was placed in silicone oil, and the dielectric breakdown voltage determined at a voltage increase rate of 50 V/sec was divided by the dielectric thickness to obtain the dielectric breakdown strength per 1 m.

These test conditions are also shown in Table 1, and the test results are shown in Table 2 below.

In addition, in the method for producing dielectric ceramic in the example, Vz
Os, LazO3+ PrhO+++ Ndz03.
S11!0:I, Ce0z.

GdzO3+ DVzOx+ Ti1t, 5rCOs
Although BaCOx and BaCOx were used, the method is not limited to this method, and BaTiO
Vz05.i, carbonate, hydroxide, etc. by heating in air. La*Os+ PraOs
+z NdzOs+ SmzOs+ Ce01゜Grh
Ox+ DyzOs+ Tilt, 5rCO and B
Even if a compound serving as aO is 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.

Further, in addition to the above-mentioned basic composition, salts, oxides, etc., which are generally considered to be fluxes, such as SiO2, Mn01°FezO5+ ZnO, etc. can be added to the extent that the characteristics are not impaired.

(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, Q is significantly improved, and the temperature coefficient of capacitance is small. It is possible to increase capacity and improve characteristics.

[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. Name of agent: Patent attorney Akira Okaji and two others Figure 1

Claims (1)

[Claims] General formula x [(BaO)_(_l_-_h_)(SrO)_h]
-yTiO_2-z(Re_(_l_-_t_)Me_
t) When expressed as O_3_/_2, (however, x+y+z
=1.00, 0.01≦h≦0.30, 0.01≦t≦
0.20, Re is one or more rare earth elements selected from La, Pr, Nd, and Sm. Me is La, Pr, Nd, Sm
One or more rare earth elements selected from rare earth elements excluding . ), x, y, z are the points a, b, c, d, e,
V_2O_5 vanadium oxide as a subcomponent to 100 parts by weight of the main component having a molar ratio range surrounded by f.
A dielectric ceramic composition characterized in that it contains 0.005 to 1.000 parts by weight calculated in the form of .