JPH06103604B2 - Dielectric ceramic composition for temperature compensation - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dielectric ceramic composition for temperature compensation, and in particular,
The present invention relates to a temperature-compensating dielectric ceramic composition used as a dielectric ceramic of a multilayer capacitor.

(Prior Art) Conventionally, as this type of temperature-compensating dielectric ceramic composition,
The MgTiO ₃ —CaTiO ₃ system porcelain was used.

(Problems to be Solved by the Invention) However, in the MgTiO ₃ —CaTiO ₃ system porcelain, the sintering temperature is as high as 1300 ° C. or higher, so the firing cost is high,
Further, when used as a dielectric ceramic of a multilayer capacitor, expensive Pd and Pt, which have a high melting point and are difficult to oxidize at high temperature, must be used as internal electrodes, which is an obstacle to cost reduction of the multilayer capacitor. Further, when fired in a non-oxidizing atmosphere, there is a problem that the porcelain is reduced and the insulation resistance value is significantly lowered.

Therefore, the main object of the present invention is a dielectric ceramic composition for temperature compensation, which can be sintered at 1000 ° C. or lower, and has a high non-resistance value of 10 ¹² Ωcm or more even when fired in a non-oxidizing atmosphere. Is to provide.

(Means for Solving Problems) The present invention contains barium oxide, calcium oxide, silicon oxide and zirconium oxide as main components, and barium oxide is converted into BaO to be X · (1-a) parts by weight, When calcium oxide is converted to CaO to be X · a parts by weight, silicon oxide is converted to SiO ₂ to be Y parts by weight, and zirconium oxide is converted to ZrO ₂ to be Z parts by weight, X, Y, Z And the value of a is 50 ≧ X ≧ 15, 84 ≧ Y ≧ 20, 65 ≧ Z ≧ 1, X
A temperature-compensating dielectric porcelain composition contained within the range of + Y + Z = 100 and 0.9 ≧ a> 0.

(Effect of the Invention) According to the present invention, for example, N ₂ gas,
Dielectric material for temperature compensation, which can be fired in a non-oxidizing atmosphere formed of gas, CO ₂ gas or H ₂ gas, has a high non-resistance of 10 ¹² Ωcm or more, and has a high Q value of 1000 or more. A porcelain composition can be obtained.

Further, if this temperature-compensating dielectric ceramic composition is used as a dielectric ceramic of a multilayer capacitor, the sintering temperature is as low as 1000 ° C. or lower, so the firing cost can be reduced, and
Since copper, a copper-based alloy, or another base metal having a low resistance value and low cost can be used as the internal electrodes, the cost of the multilayer capacitor can be reduced as compared with the conventional one.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

(Example) _{material, BaCO 3, CaCO 3, SiO} 2, ZrO 2 and Al ₂ O
₃ is weighed so that it has the composition shown in Attached Table 1 and 1 with a ball mill.
After wet-mixing for 6 hours, it was evaporated and dried to obtain a mixed powder.
Then, this mixed powder was calcined at 850 ° C. for 2 hours, 5 parts by weight of vinyl acetate as a binder was added thereto, and the mixture was wet-mixed and pulverized again in a ball mill for 16 hours. The pulverized product was evaporated to dryness, passed through a sieve and sized to obtain a fruit-like powder. The granular powder thus obtained was pressed with a dry press at a pressure of ² ton / cm ² to form a disk having a diameter of 22 mm and a thickness of 1.0 mm. Then, the disc was baked in an N ₂ gas atmosphere under the respective temperature conditions shown in Appendix 2 for 2 hours. Then, in order to avoid the characteristics of the porcelain from being changed in the characteristics of the porcelain when forming the electrodes, an In-Ga alloy was applied to the fired products to form the electrodes, which were used as samples.

Then, with respect to these samples, the following characteristics were measured under respective conditions and measuring methods, and the results are shown in Appendix 2.

(1) Firing temperature (2) Non-dielectric constant: condition of frequency 1MHz, temperature 25 ° C (3) Q value (quality factor): condition of frequency 1MHz, temperature 25 ° C (4) Capacity temperature coefficient (ppm / ° C): Based on the capacity of 25 ° C, the capacity was calculated from the capacity of 125 ° C by the following formula.

(However, capacity at C ₁ : 25 ℃, capacity at C ₂ : 125 ℃) (5) Specific resistance: Value calculated by applying a DC voltage of 500V at 25 ℃ and measuring the current value. Also, those marked with * in Appendix 2 are outside the scope of the present invention, and the others are within the scope of the present invention.

Furthermore, the results of the experimental examples shown in Appendix 1 and Appendix 2 are shown in the principal component composition diagram. In this drawing, the numbers with circles indicate the sample numbers. In this drawing, the region showing the composition ratio of the main components within the scope of the invention is
It is shown as a square with vertices A, B, C and D. That is, in the composition ratio of the above three components, BaO and CaO
And X parts by weight, SiO ₂ by Y parts by weight, and ZrO ₂ by Z parts by weight, the range of the main component of the present invention (X, Y, Z)
Is A (50,49,1), B (50,20,30), C (15,20,65), D (1
5,84,1) corresponds to the composition ratio in the region surrounded by the four vertices. However, in this principal component composition diagram, Ba
It is not shown that the relationship of 0.9 ≧ a> 0 holds when O is X. (1-a) parts by weight and CaO is X.a parts by weight.

Hereinafter, the reasons for limiting the composition of the temperature-compensating dielectric ceramic composition of the present invention will be described with reference to Attached Tables 1 and 2 and the main component composition diagram.

(1) In the principal component composition diagram, the composition outside the line segment AB connecting the vertices A and B (see sample number 6) has a Q value of 10
It is not preferable because it becomes 00 or less and the temperature coefficient of capacity becomes +100 ppm / ° C. or more, and furthermore, the glass material floats on the surface of the sintered porcelain body.

(2) In the principal component composition diagram, the composition outside the line segment AD connecting the vertices A and D (see sample number 5) has a Q value of 10
It is not preferable because it becomes 00 or less and the temperature coefficient of capacity becomes +100 ppm / ° C. or more, and furthermore, the glass material floats on the surface of the sintered porcelain body.

(3) In the main component composition diagram, the composition outside the line segment BC connecting the vertices B and C (see Sample No. 7) cannot obtain a dense sintered body even if fired at a temperature of 1150 ° C. Not preferable.

(4) In the main component composition diagram, with the composition outside the line segment CD connecting the vertices C and D (see sample number 8), a dense sintered body cannot be obtained even if fired at a temperature of 1150 ° C. Not preferable.

(5) When barium oxide is not contained in the main component, that is, when a = 1 (see sample number 14), a dense sintered body cannot be obtained even if fired at a temperature of 1150 ° C., which is not preferable. .

(6) When Al ₂ O ₃ is added in an amount of 20 parts by weight or less based on 100 parts by weight of the main component, variations in the characteristics of the porcelain are reduced and the characteristics are uniform at a certain level. However, the addition of Al ₂ O ₃
If it exceeds 0 parts by weight (see sample number 11), the sintering temperature will be 115
It is not preferable because it becomes as high as 0 ° C or higher.

[Brief description of drawings]

The drawing is a main component composition diagram showing the main component composition ratio of the composition of the present invention.

Claims (2)

[Claims] 1. Barium oxide, calcium oxide, silicon oxide and zirconium oxide are contained as main components, the barium oxide is converted into BaO to be X. (1-a) parts by weight, and the calcium oxide is converted into CaO. X.a parts by weight, the silicon oxide is converted into SiO ₂ to be Y parts by weight, and the zirconium oxide is converted into ZrO ₂ to be Z parts by weight, the values of X, Y, Z and a are A temperature-compensating dielectric porcelain composition contained within a range of 50 ≧ X ≧ 15 84 ≧ Y ≧ 20 65 ≧ Z ≧ 1 X + Y + Z = 100 0.9 ≧ a> 0. 2. The composition according to claim 1, further comprising 20 parts by weight or less (not including 0 parts by weight) of aluminum oxide converted to Al ₂ O ₃ with respect to 100 parts by weight of the main component. A dielectric ceramic composition for temperature compensation as described above.