JPS6018082B2 - porcelain dielectric material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a porcelain dielectric material that has a high yield rate, a small dielectric gap, and excellent capacitance-temperature characteristics, as well as excellent transverse rupture strength and withstand voltage characteristics.

In recent years, with the miniaturization of various circuits, there has been a demand for capacitors that are small, have a large capacity, and have excellent capacitance-temperature characteristics.

In order to cope with the large capacitance of capacitors, it is necessary to use a material with a high dielectric constant and to reduce the thickness of the porcelain body, which requires excellent resistance strength and voltage resistance characteristics. Must be. As is well known, the transverse rupture strength is related to the grain size of the porcelain body, and in order to obtain high transverse rupture strength, it is necessary to reduce the grain size. However, in general, when the grain size is small, the ratio is low, and when trying to obtain high pile rupture strength, it has been impossible to obtain a high dielectric constant. On the other hand, dielectric constant and capacitance-temperature characteristics are also contradictory; those with commercial dielectric constant have poor temperature characteristics, and conversely, those with good temperature characteristics have low dielectric constant. It is extremely difficult to obtain a dielectric ceramic material with a high dielectric constant and good capacitance-temperature characteristics.

Conventionally, as porcelain dielectric materials, materials prepared by dissolving barium titanate with other titanates, zirconate, or stannate have been put into practical use.

However, those with a dielectric constant of 2000M have poor temperature characteristics, have a grain size of 10 to 20, and have a low transverse rupture strength of about 750K9/K. In addition, materials with good capacitance-temperature characteristics, a grain size of 4 mm, and a high transverse rupture strength of about 1000 k9' exhibit only a low dielectric constant of 12,000 to 13,000. Therefore, the main object of the present invention is to improve the material composition of dielectric ceramic material so that it has a high dielectric constant, small dielectric acidity, and excellent capacitance-temperature characteristics. The object of the present invention is to provide a dielectric ceramic material that has excellent mechanical strength, voltage resistance, and capacity change characteristics over time.

Hereinafter, the present invention will be explained in detail based on embodiments.

First, a table to be referred to in the description of the examples described below will be listed.

This table shows various examples of material compositions as porcelain dielectric materials, and also lists the measured properties of each. Each sample in the above table was created as follows. Mother C03, CaC03, Mg○ (or MgC0
3) PLO4, Ti02, Sn02, Z2, and MO were blended to the desired composition ratios shown in the table, and the blended raw materials were wet-mixed in a ball mill. After dehydrating and drying this, 10
Temporarily light at 00~1200℃, after crushing, diameter 15. The side of the ship,
It was molded into a disk with a thickness of 0.5 feet. This disc is 1300~
It was fired at 140,000° C., and a silver electrode was heated at 800° C. to prepare a sample. Measurements of the electrical characteristics, etc. of each sample were performed under the following conditions.

The dielectric constant and dielectric constant (tan6) were measured using a YHP capacitance bridge at a frequency of lk.

The capacitance temperature change rate is -120qC based on the capacity.
The rate of change in capacity at 5qo and 185oo is calculated. Further, DC breakdown voltage characteristics were measured by applying a voltage to the sample held in silicone oil. In the measurement of transverse rupture strength, 5. Enemy x20.0 side x1. A plate-shaped molded product on the side of the ship was taken as a sample.

Place this sample on a knife edge separated by a distance of 1 mm,
This was measured using a push-pull gauge. The various properties measured under these conditions are shown in the table.

In the table, the items marked with * are outside the scope of this invention, and the others are within the scope of the invention.

That is, in the table, sample numbers 1, 4, 7, 13 to 18 exhibited characteristics outside the invention range, and sample numbers 4 and 15 did not become porcelain at the normal firing temperature of 1300 to 1400 oo. None of these exceed the properties of known materials and are within the composition range (sample numbers 2, 3, 5,
6, 8-12) are significantly inferior. Furthermore, as is clear from a comparison between sample number 1017 and those within the scope of the invention, the simultaneous inclusion of Pb◯ and Ni◯ is effective in improving properties. As is clear from the above examples, the composition range of the present invention is shown by the following composition formula.

(Mother, Re-b-CCaaM & PbC) ^ (Ti, -dM
ed) B03xNi0 where a: 0.02-0.15 b: 0.001-0.005 c: 0.01-0.06 d: 0<dSO. 15 However, the sintering property deteriorates and the Akatsuki uniformity becomes unstable.

On the other hand, if a exceeds 0.15, the dielectric constant decreases, which is not preferable. Further, if b is less than 0.001, the grain size becomes large and non-uniform, and if b exceeds 0.005, the dielectric constant decreases, which is not preferable. Also, c is 0.
If it is less than 0.01, the dielectric constant becomes small, and if it exceeds 0.06, the grain size becomes large, which is not preferable.

In addition, when d is 0, it is difficult to make porcelain at a firing temperature of 1300 to 1400 qo, and the dielectric constant becomes small, 0.15
Exceeding this is not preferable because the Curie point shifts significantly to the low temperature side, the dielectric constant decreases, and the dielectric loss tangent increases.

Also, when A/B is 0.995 qo, the grain size becomes large, and when it exceeds 1.04, it becomes 1300-1400 qo.
This is not preferable because it becomes difficult to make porcelain in the temperature range of .

In addition, MnC03 and Si02 were added to the composition of the porcelain body material obtained as described above as a reduction prevention agent and a mineralizing agent.
may be included.

In addition, as other additives, Cu0 is added in the range of 0.03 to 0. Kat
%, adding 0.05 to 0.4 M% of Ce02 is effective in improving the crystallization property,
Addition of wt% is effective in improving insulation resistance. As described above, according to the present invention, it is possible to obtain a porcelain transfer body material which has a high electrolysis rate, has excellent capacity temperature characteristics, and also has excellent transverse rupture strength and withstand voltage characteristics.

Claims (1)

[Claims] 1 Compositional formula (Ba_1_-_a_-_b_-_cCa_aMg_
bPb_c)_A(Ti_1_-_dMe_d)_BO
_3+xNiO In the formula, a: 0.02-0.15 b: 0.001-0.005 c: 0.01-0.06 d: 0<d≦0.15 x: 0.05-0.20wt% Me: Sn and/or Zr A/B: 0.995-1.04 Porcelain dielectric material.