JPS59214105A - 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 the Invention The present invention relates to dielectric ceramic compositions used as high stability ceramic capacitor materials.

Prior Art and its Problems Various dielectric ceramic compositions have been known as high stability ceramic capacitor materials. When manufacturing, for example, temperature-compensating multilayer ceramic capacitors using these conventional dielectric ceramic compositions, it is necessary to keep the firing temperature as low as possible, considering the negative thermal effects on the internal electrodes formed of Ag-Pd alloys, etc. sea bream. However, conventional dielectric ceramic compositions have a firing temperature of about 1300 to 1400°C;
If the firing temperature is lower than this, the dielectric constant decreases, loss increases, and the temperature coefficient of the dielectric constant increases, making it impossible to obtain satisfactory characteristics. For this reason, there has been a limit to the improvement of characteristics in, for example, temperature-compensating multilayer ceramic capacitors.

Purpose of the Invention Therefore, the present invention solves the above-mentioned conventional problems, and makes it possible to lower the firing temperature by as much as 200 to 300°C while maintaining a high dielectric constant, low loss, and a low temperature coefficient of dielectric constant. The object of the present invention is to provide a dielectric ceramic composition with good sinterability.

Structure of the Present Invention In order to achieve the above object, the dielectric ceramic composition according to the present invention has an X molar type BaO-V mol%TiOλ-2 mol%N
In the ternary composition of d2O3, the main component is a composition in which X, y, and 2 are expressed as 5≦X≦25 55≦y≦80 10≦2≦30 x+y+z=100, and as a subcomponent, a weight %pbo-bwt%Bizlhcwt%SiO
In λ-8 wt% ZnO, a, b, c and d are 0≦
It is characterized by containing 5% by weight to 20% by weight of a sintering aid expressed as a≦95 0≦b≦95 5≦C≦20 0≦d≦20 a+b+c+d=100.

A dielectric ceramic composition having such a composition can be fired at a firing temperature of around 1100°C, which is 200 to 300°C lower than conventional methods, while maintaining high electrical conductivity, low loss, and a low temperature coefficient of dielectric constant. For example, 70% Ag-30% P
It has been found that a dielectric ceramic composition suitable for manufacturing a temperature-compensating multilayer chip capacitor using a d-alloy as an internal electrode can be obtained.

The content of the present invention will be specifically explained below with reference to Examples.

Examples As a starting material for obtaining the dielectric ceramic composition of the present invention, Ba
CO3, TiO2, Nd, -OB, PbO, Bi2O
5, 5iO1, and ZnO powders were used. Note that all of the raw material powders used here had a purity of 98% or higher, except for 95% Ndz OB .

Next, the main components are BaZO3, Ti0z, and NdzOs.
Each powder was weighed so as to have the composition range shown in Table 1, and subjected to four-combining treatment in a ball mill. Then filter and dry
After pressure molding into a cylindrical shape with a diameter of 601 mm and a height of 50 mm,
2 hours at a temperature of 1150°C to 1250°C.
It was calcined in air and pulverized.

On the other hand, sintering aids PbO, si, o3, S+Ol
, ZnO were weighed to have the composition range shown in Table 1, added to the pulverized powder of the previous δ Tosei component, and mixed in a ball mill. Next, it is filtered and dried, and the diameter is 16.5ff1.
After pressure forming into a disc of 1050°C to 1150°C
It was baked for 2 hours at a temperature of °C. Silver electrodes were baked on both sides of the dielectric ceramic thus obtained to produce a ceramic capacitor. This ceramic capacitor is N002~N0.10
As shown in Table 1. Next, the dielectric constant ε, dielectric loss tan δ, and temperature coefficient of dielectric constant ppm/'C of these ceramic capacitor samples were measured under the conditions of a temperature range of -55°C to +125°C and a frequency of IMΩ. Table 1 shows typical examples of the results obtained. In addition, in Table 1, the samples of NO, 1 are BaCO3, TiO2, Nd2
This is a ceramic capacitor manufactured using a dielectric ceramic composition having a composition of only 0a, and is a comparative example to the present invention.

(Additional blank space) As is clear from Table 1, sample N011, which is a comparative example,
shows a certain level of dielectric property, but when the firing temperature is increased to 1
It is necessary to maintain the temperature at a high value of 360°C.

On the other hand, as sintering aids PbO, Bi2O3, S
Samples NO2 to 10 manufactured using the dielectric ceramic composition according to the present invention containing i 02 and ZnO had a firing temperature of 1100-1140°C, which was 20°C compared to the comparative example.
Although it is as low as 0 to 300'O, it has a high dielectric constant, a very small dielectric loss tan δ of 0.01, and a low temperature coefficient of dielectric constant.

The range that exhibits excellent dielectric properties and temperature characteristics at such a low firing temperature is 7 mol%BaO-'1 mol%TiOλ-Z mol%Nde0! In the ternary composition of x, y and U
'z is within the composition range expressed as 5≦X≦25 55≦y≦80 10≦Z≦30) (+y+Z=100, and the subcomponents and -c weight%5i02
d In the nail part % ZnO, a, b, C and d are 0≦a≦95 0≦b≦95 5≦C≦20 0≦d≦20 a + b + c + d = l OO The composition is limited to a composition containing 5% to 20% by weight of the binder.

If the values of x, y, and z are outside the above ranges, the dielectric constant becomes small, the dielectric loss becomes large, or the temperature characteristic of the dielectric constant becomes large, and practicality is lost.

Next, if the values of a, b, C, and d are outside the above ranges, the firing temperature will become high and the object of the present invention will not be met. Further, if the content of the sintering aid is less than 5% by weight, the firing temperature will be high, and if it is more than 20% by weight, the dielectric loss will increase or the temperature coefficient of the dielectric constant will increase, making it impractical.

As described above, the dielectric ceramic composition according to the present invention has the following effects:
X molar form Ba0-y molar form Ti02-z molar form Nd2O
! In the ternary composition of l, the main component is a composition in which x, y, and 2 are selected to a limited predetermined value, and as a subcomponent, a weight % pbo - b weight % Bi20B
-c wt% 5i02d wt% ZnO, a, b,
Since it is characterized by containing 5% to 20% by weight of sintering aids that limit c and d to predetermined values, it maintains high dielectric constant, low loss, and low temperature coefficient of dielectric constant. , it is possible to provide a dielectric ceramic composition with good sinterability and which can lower the firing temperature by as much as 200 to 300°C.

Claims (1)

[Claims] (1) In a ternary composition of X molar form Ba0-7 mol% Ti02-z molar form Nd, -1o. The main component is a composition expressed as , and the subcomponents are a weight % pbo-bz- amount % Bi, (h - c weight % 5i
(In the b - d amount of ZnO, a, b, c and d are expressed as O≦a≦95 0≦b≦95 5≦C≦20 0≦d≦20 a+b+c+d=10−0 A dielectric ceramic composition characterized by containing 5% to 20% by weight of a material.