JPS63289709A - Nonreducible dielectric ceramic constituent - Google Patents

Abstract

PURPOSE:To aim at reduction in electrode cost with the promotion of large capacity in a laminated condenser by containing a specific amount of Mn and SiO2 in a main component to be expressed with a formular (Sr1-xCax)m(Ti1-yZry) O3 as a subcomponent. CONSTITUTION:A main component is expressed with formular (Sr1-xCax)m (Ti1-yZry)O3, and x, y and m are of 0.30<=x<=0.50, 0.92<=y<=0.98 and 0.95<=m<=1.08, respectively. And, Mn is converted into MnO2 and its 0.01-4pts. wt. and a 2.00-8.00pts.wt. of SiO2 are contained in this main component 100pts. wt. as a subcomponent. A nonreducible dielectric ceramic constituent of suchlike composition is used as material for a laminated condenser and, what is more, a base metal such as Ni, Fe, Cr or the like is usable as an internal electrode, thus reduction in cost of the electrode with the promotion of large capacity in the laminated condenser can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a non-reducible dielectric ceramic composition, and more particularly to a non-reducible dielectric ceramic composition suitable as a dielectric material for laminated capacitors and the like.

(Prior art) Conventionally, when manufacturing a multilayer capacitor, a metal layer that will become an internal electrode is formed by printing on the top surface of a dielectric green sheet, and after stacking a plurality of layers and crimping and integrating them, A firing process is used.

(Problems to be Solved by the Invention) Conventional dielectric ceramic materials have the property of being reduced and turned into semiconductors when fired under neutral or reducing low oxygen partial pressure. Therefore, materials such as palladium and platinum, which do not melt at the sintering temperature of the dielectric ceramic material and do not oxidize even when fired under high oxygen partial pressures that do not convert the dielectric ceramic material into a semiconductor, can be used as materials for the internal electrodes. This required the use of noble metals, which was a major hindrance to making multilayer capacitors smaller, larger in capacity, and lower in price.

Therefore, in order to solve the above-mentioned problems, it has been desired to use an inexpensive base metal such as nickel as a material for the internal electrodes. However, when such base metals are used as internal electrode materials and fired under conventional conditions,
The electrode material will oxidize or melt. Therefore, in order to use such base metals as materials for internal electrodes, they do not turn into semiconductors even when fired at low temperatures in a neutral or reducing atmosphere with low oxygen partial pressure, and are used as dielectric ceramic materials for capacitors. There was a need for dielectric porcelain materials with sufficient resistivity and excellent dielectric properties.

Therefore, the main object of the present invention is to sinter at a temperature of 1.360°C or lower in a neutral or reducing atmosphere with a low oxygen partial pressure, and to achieve a temperature coefficient of capacitance without being reduced. The absolute value of is below 100 pp ma℃,
The dielectric constant is 40 or more, the dielectric loss is 0.1% or less,
It is an object of the present invention to provide a non-reducible dielectric ceramic composition having a specific resistance at 20°C of 1X10''Ω- or more.

(Means for Solving the Problems) This invention provides a general formula (S r+-x Ca, )S
It is represented by (Ti1-, Zry)03, and the molar ratios x, y and m of this general formula are 0.30≦x≦0.
50, 0.92≦y≦0.98, and 0.95≦m≦
For the main component in the range of 1.08, 100 parts by weight of the main component, as a subcomponent, Mn converted to Mn0z is 0.
．． 01 to 4.00 parts by weight, and 2.00 to 5i02
This is a non-reducible dielectric ceramic composition containing 8.00 parts by weight.

(Effect of the invention) According to this invention, in a reducing atmosphere, 1.36
Sintered at 0°C or lower, the absolute value of the temperature coefficient of capacitance versus temperature is 1100 pp/'c or lower, the dielectric constant is 40 or higher, the dielectric loss is 0.1% or lower, and the specific resistance at 20°C is A non-reducible dielectric ceramic composition having a characteristic of 1×10'3 ΩCm or more can be obtained. Therefore, if this non-reducible dielectric ceramic composition is used as a material for a multilayer capacitor, base metals such as Ni, Fe, and Cr can be used as internal electrodes. Therefore, it is possible to eliminate the increase in cost of electrodes due to an increase in the capacity of a multilayer capacitor, and it is possible to provide a low-cost multilayer capacitor.

The above objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments.

(Example) First, industrial 3rCOz and CacO3 were used as starting materials.
, Zr0z, Ti0z, Mn0z and Sin were prepared. Then, these raw materials are given the composition formula (Srl-x
Cax )m (Tl+-y Zry)0, +M
In nO2+SiO2, the compositions were blended to have the blending ratio shown in Table 1.

Next, these blended raw materials were wet mixed in a ball mill, pulverized, and then evaporated to dryness.
It was calcined at ℃ for 2 hours. Then, 5 parts by weight of a vinyl acetate binder was added as a binding material to the calcined raw materials, and wet-mixed in a ball mill. Furthermore, this mixture was evaporated to dryness and then sized to obtain a powder raw material. 2.5 tons of the obtained powder raw material
on/CII! It was molded into a disk shape with a diameter of 20mm and a thickness of 1.2mm under a pressure of .

Next, this disc-shaped molded product was placed in an alumina box lined with zirconia powder, and left in a natural atmosphere for 500 min.
The vinyl acetate binder was burned for 2 hours at .degree. Thereafter, in a reducing gas atmosphere with a volume ratio of H2:Nz=3:100, the disc-shaped molded product was heated to 1,300 to 1,440
The device was baked at ℃ for 2 hours to obtain a device. An In-Ga alloy was applied to both sides of the obtained element to form electrodes, thereby creating a sample (capacitor).

Then, the dielectric constant ε, dielectric loss tan δ,
Temperature coefficient of capacitance α (ppm/”C) and specific resistance ρ
(Ω mark) was measured.

Note that the dielectric loss tan δ is 1kHz, IVrms, 2
Measurement was performed at 0°C.

Furthermore, the temperature coefficient α (ppm/”C) of capacitance is 2
It was determined from the capacitance CtO at 0°C and the capacitance C115 at 85°C using the following equation.

In addition, the specific resistance ρ (Ωcm) is 500■ at 20°C.
It was determined from the current value that flows when a DC voltage of .

These results are shown in Table 2.

Next, the reason for limiting the numerical values of the main components of the non-reducible dielectric ceramic composition according to the present invention will be explained.

In other words, if X is smaller than 0.30 as in Sample No. 1, or larger than 0.50 as in Sample No. 5, the firing temperature will exceed 1,360°C and the temperature coefficient of capacitance will increase. The absolute value of is greater than 1100 pp/°C, which is not preferable.

Also, if y is smaller than 0.92 as in sample number 9,
The absolute value of the temperature coefficient of capacitance is 100 ppm/”
C, and the specific resistance becomes less than 1×10'3 Ω■, which is not preferable. Furthermore, as in sample number 6, when y is larger than 0.98, the firing temperature is 1,360
℃ and the absolute value of the temperature coefficient of capacitance is 1100
pp/'C, which is undesirable.

Further, as in sample number 10, if m is smaller than 0.95, the specific resistance becomes smaller than 1×10 13 Ωcm and the dielectric loss becomes larger than 0.1%, which is not preferable. Furthermore, as in sample number 14, when m is larger than 1.08, the firing temperature exceeds 1,360°C, which is not preferable.

Next, the reason for limiting the content of subcomponents will be explained.

As in sample number 15, M per 100 parts by weight of the main component.
If the content of nO is less than 0.03 parts by weight, the firing temperature will exceed 1.360°C, the dielectric loss will be greater than 0.1%, and the resistivity will also be smaller than 1 x 10'3 Ω. I don't like it.

In addition, as in sample number 19, the content of M n O2 is 4
．． If the amount is more than 0.00 parts by weight, the specific resistance becomes less than 1×10'3 Ω, which is not preferable.

Furthermore, if the content of Sin is less than 2.00 parts by weight with respect to 100 parts by weight of the main component, as in sample number 20,
It is not preferable that the firing temperature exceeds 1.360°C.

In addition, as in sample number 24, the content of SiO□ is 8.0
If the amount is more than 0 parts by weight, the dielectric constant will be less than 40 and the resistivity will be less than 1X10'' Ωcm, which is not preferable.

In contrast, for samples within the scope of this invention, 1.36
Sintered at temperatures below 0°C, with an absolute value of temperature coefficient of capacitance of 11
00pp/'C or less, dielectric constant is 40 or more, dielectric loss is 0.1% or less, and resistivity at 2°C is 1×
It is 10'3Ω or more.

In this example, the disc-shaped molded product was fired in a reducing atmosphere consisting of N z Hz, but Ar, Co
, Cot , Hz , Nz , or a mixed gas atmosphere thereof, the disc-shaped molded product may be fired.

Claims (1)

[Claims] General formula (Sr_1_−_xCa_x)_m(Ti_1_
−_yZr_y)O_3, and the molar ratios x, y, and m of this general formula are 0.30≦x≦0.50, 0.92≦y≦0.98, and 0.95≦m≦, respectively. 1.08 parts by weight of the main component, as subcomponents, Mn is 0.01 to 4.00 parts by weight converted to MnO_2, and SiO_2 is 2.00 to 4.00 parts by weight. A non-reducible dielectric ceramic composition containing 8.00 parts by weight.