JPS6050005B2 - dielectric porcelain composition - Google Patents

Description

[Detailed description of the invention] The present invention produces a dielectric material with high insulation resistance and dielectric constant and low dielectric loss by sintering in a reducing or neutral atmosphere and then heat-treating in an oxidizing atmosphere. Regarding reduction and reoxidation dielectric ceramic compositions, more specifically, dielectric ceramic compositions that are ideal for manufacturing ceramic multilayer capacitors by coating a green sheet with a conductor paste containing nickel as a main component and sintering it. Regarding.

Conventional multilayer ceramic capacitors are made by stacking and compressing multiple dielectric green sheets (green sheets) printed with conductor pastes of precious metals such as platinum and palladium, and then firing them at high temperatures of 1100 to 1400 degrees Celsius in an oxidizing atmosphere. After that, an external extraction electrode is provided.

However, since electrode materials such as platinum and palladium are expensive, they are not suitable for consumer products. H→Frr
j-ear R maπμn low,, 1゛,j,l゛,”
It was impossible to provide. In order to solve this type of problem, attempts have been made to form the internal electrodes of multilayer ceramic capacitors using a conductive paste containing nickel as a main component. However, nickel oxidizes when heated at around 300°C in an oxidizing atmosphere, making it impossible to use as an electrode. Or it must be fired in a reducing atmosphere. Therefore, a dielectric ceramic composition that can be sintered in a neutral or reducing atmosphere is required. On the other hand, when manufacturing a multilayer ceramic capacitor, it is necessary to form external lead-out electrodes by applying silver paste, etc., and it may also be necessary to form thick film resistors.

When forming external lead-out electrodes, etc., it is generally necessary to perform heat treatment at 800 to 1000° C. in an oxidizing atmosphere. Therefore, for dielectric ceramic compositions as well, two processes are required: firing at about 1100 to 14000C in a neutral or reducing atmosphere and heat treatment at about 800 to 1000C in an oxidizing atmosphere. administered. Therefore, there is a need for a dielectric ceramic composition that can stably obtain a dielectric ceramic with desired characteristics through the above two heat treatments. Therefore, an object of the present invention is to provide a dielectric ceramic composition that satisfies the above requirements.

The present invention for achieving the above object includes ((Bal-0Sr0)0)5・Til-YZry)0
．． It is represented by the compositional formula of X. ．． y,. k is 0.02
≦X≦0.30s0.01≦y≦0.26N1.001
The present invention relates to a dielectric ceramic composition characterized in that the value is in the range of ≦k≦1.03.

According to the above invention, in a neutral or reducing atmosphere, about 110
Approximately 800 to 1 when fired at 0 to 1400°C and in an oxidizing atmosphere
By heat treatment at 000℃, the relative dielectric constant ε5 becomes 5.
500 or more, it becomes possible to obtain a dielectric material with a dielectric loss Tan δ of 2% or less.

Further, within a preferable range, it is possible to obtain a dielectric material in which ε9 is 20,000 or more and Tan δ is 2%. Further, it becomes possible to stably and mass-produce dielectrics. Therefore, it is possible to provide a dielectric ceramic composition particularly suitable for a laminated ceramic capacitor in which internal electrodes are formed from a conductive paste containing nickel as a main component. Next, examples of the present invention will be described. Example 1 BacO3, SrcO3, T with a purity of 99% or more
Prepare iO2 and ZrO2 powders as starting materials,
Composition formula ((Bal-0Sr0)0)1・(TIl-YZ
r,)02 Kll-X. ．． xll-Y,. Each raw material was weighed and wet-mixed so that y had the values shown in Table 1 A and B.

Next, this mixture was dehydrated and dried, polyvinyl alcohol was added and granulated, and the granulated product was pressure molded at 1000 k9/d. Next, it is fired in an oxidizing atmosphere at 600°C using an electric furnace, and then the volume ratio *'l'H2/N2=1.
In a reducing atmosphere of 5/100, the temperature was raised to a temperature in the range of 1330°C to 1380°C as shown in the sintering temperature column of Table 1, and this temperature was maintained for 3 hours to obtain a diameter of 13.2Wr! R
1 thickness 0.84T! A disk-shaped sintered body of Rln was manufactured.
Next, an In-Ga alloy was applied to both sides of this sintered body to form an electrode on the entire surface, and this was used as a sample for measuring the specific resistance of the sintered body in a reducing atmosphere. The voltage was applied for a minute, the insulation resistance was measured, and the specific resistance ρ1 before the oxidation treatment was determined by conversion.

As a result, ρ1 of each sample was the value shown in Table 1. In addition, a sintered body produced in the same manner as above (a sintered body before oxidation without an In-Ga electrode) was placed in an electric furnace, and all samples were oxidized and fired at 800°C in an oxidizing atmosphere for 1 hour. In-Ga alloy electrodes were formed on both main surfaces of this oxidized sintered body, and this was used as a sample for measuring the specific resistance ρ2 after oxidation. The insulation resistance was measured, and the specific resistance (ρ2) was determined by conversion.

As a result, the specific resistance ρ2 of each sample was the value shown in Table 1. In addition, silver paste was applied to both main surfaces of the sintered body after firing in the same reducing atmosphere as above (the sintered body before oxidation), and heat treatment was performed at 800°C for 1 hour in an oxidizing atmosphere. All samples were subjected to the same process to form an electrode of 11 TI$Lφ, which was used as a measurement sample for relative permittivity Es and dielectric loss Tanδ, and ε5 and Tanδ were measured at a frequency of 1 kHz. The results are shown in Table 1. The results were obtained. As is clear from Table 1 above, sample numbers 2-6, 8, 12-15, 17-2
According to the composition according to No. 0, dielectric porcelain having a relative permittivity ε5 of 5500 or more and a Tan δ of 2% or less can be obtained by both firing in a reducing atmosphere and firing in an oxidizing atmosphere. I can do it. On the other hand, as shown in sample number 9, x is 0.
When 0.01 is smaller than 02, that is, when Sr is 0.1 mole, ρ2 is as low as 1.2×1 CfMΩ·G and cannot be used as a dielectric ceramic composition. Therefore, E5 and Tan δ of this sample were not measured. In addition, as shown in sample number 1, when x is 0.32, which is larger than 0.3 (when Sr is 0.32 (when Sr is 0.32 mol), both ρ2 and Tanδ have good values. However, Es is 3
300, which makes it impossible to achieve the purpose of the present invention. Furthermore, as shown in sample number 10, when y is O (Z
When r is not added), ρ2 is 1.5×1σMΩ・a
This is so low that it cannot be used as a dielectric ceramic composition. Therefore, ε9 and Tanδ of this sample were not measured. Further, as shown in sample number 7, when y becomes 0.27, which is 0.26 or more, ε8 becomes low and the object of the present invention cannot be achieved. Also, as shown in sample number 11, when the value of k becomes 1.00, which is smaller than 1.001, ρ2
is 1.5×10 MΩ●d, and cannot be used as a dielectric ceramic composition. Moreover, as shown in sample number 16, when the value of k becomes 1.04, which is larger than 1.03,
Sintering becomes impossible. Therefore, X. y,. The preferred range of k is x=0.02-0.30, y=0.01-0.26
, k=1.001 to 1.03. That is,
The preferred component range of Sr is 0.02 to 0.30 mol, Z
It can be seen that the preferred component range of r is 0.01 to 0.26 mol, and the preferred component range of k is 1.001 to 1.03. Further, especially according to the compositions of sample numbers 6 and 12, it is possible to obtain an extremely excellent dielectric material with a high ε5 of 20,000 or more and a low Tan δ of 2% or less.

Therefore, a more preferred range for x is about 0.1-0.2, and a more preferred range for y is about 0.1-0.2.
Regarding sample number 4, the temperature was varied in the range of -25 to +85 using a constant temperature bath, and the specific resistance ρ after oxidation was
2. When the changes in relative dielectric constant ε8 and Tan δ were investigated, the results were as shown in FIGS. 1 to 3. However, Es is shown in FIG. 2 as a rate of change. As is clear from this result, ρ2 tends to decrease as the temperature increases. However, ρ2 at +85° C. is 9.1×101 MΩ·d, which is a practically sufficient value. ε5 peaks at 17C and rapidly decreases around this point. However, -25℃~+85℃
The change therebetween is in the range of +20% to -80%, which is a practically usable characteristic. Furthermore, Tan δ tends to increase as the temperature decreases. However, since it is 3% at -25°C, this is a practically sufficient characteristic. Also, for samples other than sample number 4 within the scope of the present invention, ρ2 was 1 at +85°C.
CPM Ω・Tan or higher, and Tan δ is 3% at -25℃
It was below. Furthermore, although the temperature characteristics of ε5 differ slightly depending on the composition, it was confirmed that it can be used for various purposes. Example 2 A sintered body was produced in the same manner as in Example 1, except that the same composition as Sample No. 4 of Example 1 was used, and only the firing conditions were changed as shown in Table 2. Similarly, ρ1 ε5,
When Tanδ and ρ2 were measured, the results shown in Table 2 were obtained.

The sintering temperature in a neutral or 5:8 reducing atmosphere was 1340° C. for each sample, and the heating temperature in an oxidizing atmosphere was 800° C. for each sample. Also, the firing atmosphere H2/ in Table 2
N2 indicates the volume ratio in a neutral or reducing atmosphere. As is clear from the results in Table 2, the specific resistance ρ1 before oxidation firing becomes smaller as the reducing atmosphere becomes stronger, but after oxidation firing it becomes more than 3.0 The effects of strength and weakness can be erased. Also, ρ2,
Both Tan δ also have good values. Therefore, according to the dielectric ceramic composition of the present invention, it is possible to obtain a sintered body without being affected by variations in sintering conditions due to a reducing atmosphere, and mass production of capacitors with uniform characteristics is possible. become. Example 3 The same composition as Sample No. 4 of Example 1 was calcined, and 15% by weight of an aqueous solution of an acrylic acid ester polymer water-soluble binder, glycerin, and condensed phosphate was added to the calcined raw material. (4) Grind and mix with water in a ball mill to prepare a slip, and after defoaming treatment, prepare a ceramic green sheet with a thickness of 60 μm using the doctor blade method, and dry. After that, it was punched out into a rectangular shape using a press, and one side of the punched ceramic green sheet was coated with 91% by weight of Ni powder, 1.0% by weight of MnO powder, and P.
A conductive paste consisting of 8.0% by weight of bO-BaO-SiO2 glass was printed so that the printed parts faced each other. Two of the above green sheets were stacked together and bonded together under heat.

The thus integrated product is heated in air to 600°C to burn off the binder, and then H2/N2
=1.5/100 in a reducing atmosphere up to 1340℃1
The temperature was raised at a rate of 00° C./h, maintained at this temperature for 2 hours, and then cooled to 800° C. at a rate of 1000 C/hr, and then allowed to cool naturally while maintaining this atmosphere to room temperature. Next, silver paste is applied to the laminated sintered body as an electrode for external extraction, and fired at 800°C for about 1 hour in an oxidizing atmosphere to bake the silver paste and oxidize the sintered body.
Width 4.8w1n1 length! Size 5.6Tn1 thickness 1.07wt
completed a ceramic multilayer capacitor.

When we measured the characteristics of this capacitor, we found that the capacitance C was 1.34μF (1kHz), and the dielectric loss (Tanδ
) is 2.50% (1kHz), specific resistance is 4 x 103MΩ
●c! n (200C). As described above, according to the composition of the present invention, it is possible to use a conductive paste containing nickel as a main component, to obtain a sintered body by heat treatment at the same time as this paste, and to form an external lead-out electrode. At the same time, the sintered body is oxidized during heat treatment, making it possible to complete a ceramic multilayer capacitor. Therefore, it is an optimal composition for multilayer capacitors having internal electrodes mainly composed of nickel. Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and can be modified in various ways without departing from the gist of the present invention.

For example, the same effects as in Example 1 can be obtained by using a combination of Ar and H2 or a combination of CO2 and CO as the neutral or reducing atmosphere. In addition, within the range that satisfies the characteristics aimed at in the present invention, a trace amount of MnO2,
Fe2O3, Ae2O3, SiO2, clay, etc. may be added as mineralizers. For example, for the composition of the invention, M
rO2 0.1-0.05% by weight, clay 0.2-0
．． By adding it within the range of heel weight %, it is possible to improve the sinterability which affects the electrical properties.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are characteristic diagrams showing changes in ρ2, E5, and Tanδ due to temperature in sample number 4 of the example of the present invention. In the symbols used in the drawings, ρ2 is the specific resistance after reoxidation, ε8 is the relative permittivity, and Tanδ is the dielectric loss.

Claims (1)

[Claims] 1 {(Ba_1_−_xSr_x)O}_k・Ti_
1_-_yZr_y)O_2 and where x, y, and k are in the range of 0.02≦x≦0.30 0.01≦y≦0.26 1.001≦k≦1.03 1. A dielectric ceramic composition characterized in that: