JPS63193401A - dielectric porcelain composition - Google Patents

Abstract

(57) [Summary] 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 a high dielectric constant, a small temperature coefficient, an excellent quality Q, and a high insulation resistance.

2. Description of the Related Art A dielectric material with a small temperature coefficient has been required as a capacitor element, and the following systems are known as dielectric ceramic compositions.

M g O-T i O2-Co O-based La O-2
TiO2-CaTiO3-2M g O-T i O2
System TiO-BaTiO3-B 1203 -La203 system S rZ ro3- S ro -Nb20s-Ca
Problems to be solved by the T i O3-based invention However, these compositions have a low dielectric constant, and 5rZr
The O-3rO-Nb205-CaTiO3 system had a problem in that the quality Q was also poor.

The object of the present invention is to obtain a dielectric ceramic having a high dielectric constant, a small temperature coefficient, an excellent quality Q, and a high insulation resistance.

Means for Solving the Problem In order to solve this problem, the dielectric ceramic composition of the present invention has the following formula: .

For a composition with a range of 2 molar ratios surrounded by b, c, and d, PbO is 15% by weight excluding 0% by weight. It is a triangular diagram showing the composition range of the components, and the reason why the composition range of the main component is limited will be explained with reference to the diagram. In region A, sintering becomes difficult and the dielectric constant, quality Q, and insulation resistance decrease. In region B, the temperature coefficient becomes too large on the - (minus) side, making it impractical. In the C region, the temperature coefficient becomes large on the + (plus) side and the dielectric constant is small. In the D region, sintering becomes difficult, and the dielectric constant, quality Q, and insulation resistance decrease. Also, 0<
In the range of 1≦0.25, increasing m increases the temperature coefficient to +
By shifting to the (plus) side and selecting an appropriate composition, a composition with a large dielectric constant near the temperature coefficient NPO can be obtained.

When l exceeds 0.25, sintering becomes difficult, and the dielectric constant, quality Q, and insulation resistance decrease. Also, 0.05≦n<
In the range of 1.00, increasing n increases the temperature coefficient to +
By shifting to the (plus) side and selecting an appropriate composition, a composition with a large dielectric constant near the temperature coefficient NPO can be obtained. If n is less than O or OS, the temperature coefficient becomes large on the - (minus) side, making it impractical. Furthermore, with regard to the addition of PbO, the dielectric constant can be increased as the amount added is increased, and the temperature coefficient can be shifted to the + (plus) side. A composition with a large dielectric constant can be obtained.

The present invention further provides manganese, chromium,
At least one element selected from the group consisting of iron, nickel, cobalt and silicon is added to MnO2,
Cr2O3, Fed, Nip.

0.05 to 0.05 of the above main components in terms of Coo and SlO□
It can be configured such that 1.00% by weight is added.

These additives have the effect of improving the sinterability of porcelain,
If the amount added is less than 0.05% by weight, there is no effect of the addition.
When it exceeds 1,600% by weight, the dielectric constant decreases and becomes impractical.

Function: Using the dielectric ceramic composition of the present invention, it is possible to obtain a dielectric ceramic having a high dielectric constant, a small temperature coefficient, an excellent quality Q, and a high insulation resistance.

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

Example 1 Starting materials include chemically highly purified BaCO3, TlO2,
ZrO2, Nd2O3, Sm2O3, and PbO powders were weighed to have the composition shown in Table 1, and put into a rubber-lined ball mill equipped with an agate ball together with pure water.
After wet mixing, the mixture was dehydrated and dried. This dry powder was placed in a high alumina crucible and calcined at 1000°C for 2 hours. This calcined powder was put into a rubber-lined ball mill equipped with agate balls together with pure water, and wet-pulverized. After dehydrating and drying this pulverized material, it is added to powder with a concentration of 5% by weight as a binder.
After adding 9% by weight of a polyvinyl alcohol solution to make the mixture homogeneous, the mixture was sized through a 32-mesh sieve. The sized powder is molded using a mold and a hydraulic press at a pressure of 1 ton.
The molded product was molded to a diameter of 7 cm2, 15 Ill, and a thickness of 0.4111, and the molded product was placed in a zirconia sagger and fired in air at the temperature shown in Table 1 for 2 hours to produce dielectric porcelain having the composition shown in Table 1. I got it.

The electrical properties of these samples were determined by baking silver electrodes on both sides of the samples, and measuring the dielectric constant, quality Q, and temperature coefficient using a YHP digital LCR meter model 4275A at a measurement temperature of 25°C and a measurement voltage of 1. OV was determined by measurement using a constant frequency IMH2.The temperature coefficient was determined using the following formula using the capacitance value at 25°C as a reference.

Temperature coefficient (ppm/'C) = [(C-C) / (Cx6(1)]xlOG85℃
25° C. 25° C. Insulation resistance was determined by measurement using HR meter model 4329A manufactured by YHP Co., Ltd. at a measurement voltage of 50 V DC and a measurement time of 1 minute. The test results are shown in Table 1.

Example 2 Chemically highly purified B a CO3, TlO as starting materials
2, ZrO2, Nd2O3, Sm2O3, Pbo, Mn
O, Cr2O3, Fed, Nip.

Coo and SiO□ powders were weighed to have the compositions shown in Table 2, and thereafter treated in the same manner as in Example 1 to obtain dielectric ceramics having the compositions shown in Table 2.

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

Effects of the Invention As described above, according to the present invention, a dielectric ceramic having a high dielectric constant, a small temperature coefficient, an excellent quality Q, and a high insulation resistance can be obtained. Furthermore, the firing temperature can be lowered by adding manganese, chromium, iron, nickel, cobalt, and silicon.

Furthermore, since the obtained dielectric ceramic has a high dielectric constant, the element body can be made extremely small, which is effective for miniaturizing circuits.

[Brief explanation of the drawing]

FIG. 1 is a triangular diagram showing the composition range of the main components according to the present invention. Patent applicant Matsushita Electric Industrial Co., Ltd. (Nd203)
1-n (Sm203)n (Ele) Figure 1

Claims (2)

[Claims] (1) General formula xBaO-y[(TiO_2)_1_-_m(ZrO_
2)_m]-z[(Nd_2O_3)_1_-_n(S
m_2O_3)_n] However, when expressed as x+y+z=1.00 0<m≦0.25 0.05≦n<1.00, x, y, and z are each point a, b,
For compositions in the molar ratio range surrounded by c, d, P
A dielectric ceramic composition characterized in that bO is added in an amount of 15% by weight or less excluding 0% by weight. (2) At least one element selected from the group consisting of manganese, chromium, iron, nickel, cobalt and silicon, MnO_2, Cr_2O_3, FeO,
0 of the main components in terms of NiO, CoO and SiO_2
．． 05 to 1.00% by weight of the dielectric ceramic composition according to claim (1).