JPS63121209A - Non-reducing dielectric ceramic 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] Industrial application field> The present invention is directed to a non-oxidizing atmosphere with a low oxygen partial pressure, and
Sintered at a temperature of 360℃ or less, the rate of change in capacitance with respect to temperature is small, the dielectric constant is 200 or more, and the dielectric loss is 0.
．． 2% or less, and the specific resistance at 20°C is 1 x 101
The present invention relates to a non-reducible dielectric ceramic composition characterized in that the resistance is larger than 2Ωa.

<Conventional technology and its problems> Conventionally, small, large-capacity, and highly reliable ceramic multilayer capacitors have been obtained by using dielectric materials mainly made of barium titanate. It is used in the electronic circuits of various products such as grips, TV receivers, electronic clocks, and radio receivers.

However, these composition systems mainly composed of barium titanate require firing at 1,300 to 1,400°C in a natural atmosphere, so they have the disadvantage of requiring the use of noble metals such as platinum and palladium for the internal electrodes. had.

That is, the material for the internal electrodes should: (1) not melt or evaporate at the temperature at which the dielectric is sintered;

(2) It should not be oxidized by the firing atmosphere or react by coming into contact with the dielectric.

It was necessary to satisfy the following conditions.

Therefore, in order to reduce the cost of ceramic $A-layer capacitors, it is necessary to change the internal electrodes from negative metals to base metals. However, in order to use base metals such as nickel as the internal electrode material, it is necessary to use non-negative metals with low oxygen partial pressure. There was a need for dielectric porcelain that could be sintered at a firing temperature of 1360° C. or lower in an oxidizing atmosphere.

Means for Solving the Problems> This invention has been made to solve the above problems, and its gist is (Sr1-x C
In the compositional formula represented by a 0.020.0
．． When the range of 98≦m≦1.02 is satisfied and the above main component is 1001ffi parts, 1 is 1 as a subcomponent.
The purpose of the present invention is to provide a non-reducible dielectric ceramic composition characterized by containing 0.01 to 2.00 parts by weight of SL Ot in terms of 1n Ot, or 3.00 parts by weight or less of SL Ot. It is something to do.

<Operation> The compositional formula (Sr1-x Cax ) m (r
, 1-yM;+, )03, the coefficients x1y and m in the above formula are 0 in molar ratio.
．． 3≦x≦0.5.0.001≦y≦0.020.0.
Let's talk about the reason for limiting 98≦m≦1.02.

If the coefficient X is smaller than 0.3, the firing temperature will exceed 1360° C., and the rate of change in capacitance Ω with respect to temperature will become large, which is not preferable. Moreover, if it is larger than 0.5, the rate of change of capacitance with respect to temperature becomes large, which is not preferable.

Setting the coefficient y in the range o, ooi≦y≦0.020 is undesirable because if it is smaller than o, ooi, the firing temperature will be higher than 1360°C, and if it is larger than 0,020, it will cause dielectric loss. This is because (tan δ) becomes larger than 0.2% and the specific resistance becomes lower than 1×10 12 Ω, which is not preferable.

Regarding the coefficient m, when the value is smaller than 0.98, the firing temperature exceeds 1360°C and tan δ is 0.
．． 2% and the specific resistance is 1×1012Ωα
When m is larger than 1.02, the dielectric constant is smaller than 200 and tan δ is 0.
If it becomes larger than 2%, the specific resistance becomes lower than 1×10 12 Ωa, which is not preferable.

Next, we will talk about the reason for limiting the range of the added amount of subcomponents. When the main component is 100 parts by weight, the added amount of insects is 0.0
If it is less than 1 layered part, the firing temperature will exceed 1360℃,
And tan δ is larger than 0.2%, and the specific resistance is also 1×
It becomes lower than 1012Ωσ, which is not preferable. Moreover, when the number of 200 overlap portions increases, the firing temperature exceeds 1360° C. and the tan δ becomes larger than 0.2%, which is not preferable.

The purpose of adding SL Or is to adjust the firing temperature, but if the added O exceeds 3.00 parts ffi, tan δ will become larger than 0.2% and the specific resistance will become lower than 1 × 10 12 Ωα. This is not desirable because it becomes low.

<Example> Hereinafter, this invention will be explained in detail with reference to Examples.

Industrial Sr Co 3 , Ca Co as starting materials
s, I'b Co s, Ti(h, r'ho7,
Compositional formula (Sr 1-x Ca 8) using SL Ot
,.

<T1%)Os+t'hOt+5LOtNij5ite, respectively, were blended so that the blending ratios shown in Table 1 were obtained.

Next, these raw materials were wet mixed in a ball mill, pulverized, evaporated to dryness, and calcined at 1150° C. for 2 hours in a natural atmosphere. Next, 5 parts by weight of a vinyl acetate binder as a binder was added to the calcined raw material, wet mixed using a ball mill, and then subjected to evaporation drying and sizing processes, and the resulting powder raw material was heated at a pressure of 2.5 tons 4. It was molded into a disk shape with a diameter of 10 mm and a thickness of 1.2 mm.

Next, this disk was placed in an alumina container with zirconia powder as a powder, and after burning the 11 vinyl binder at 500℃ in a natural atmosphere for 2 hours, the volume ratio was 82 /
In a reducing gas atmosphere of Na-3/100, 12
It was baked at 70 to 1360°C for 2 hours.

A min-yoke alloy is applied to both sides of the sintered element, and the dielectric constant (ε
) and dielectric loss (tanδ) at 1KHz.

Measured under the conditions of 1 Vris and 20°C.

Note that the capacitance change rate with respect to temperature was measured at -25°C and 85°C with the capacitance value at 20°C as a reference.

Further, the specific resistance (ρ) was determined from the value of the current flowing when a DC voltage of 500 μm was applied at 20°C. The results are shown in Table 2. Note that sample numbers marked with * are outside the scope of the claims of this invention.

Table 1 Table 2 Effects of the invention> From the above table, it can be seen that in the composition of this invention, the firing temperature is 1.
360°C or less, the rate of change in capacitance n with respect to temperature is small, the dielectric constant is 200 or more, the dielectric loss is 0.2% or less, and the specific resistance at 20°C is 1 x 1012 Ωa or more. This was recognized.

In the examples, a non-oxidizing atmosphere consisting of N, -82 was used as the firing atmosphere, but Ar, CO, CO2, N
2, N2, and a mixed atmosphere gas thereof may be used.

Claims (1)

[Claims] (1) Composition formula (Sr_1_-_xCa_x)_m(Ti
In a dielectric ceramic composition whose main component is a substance represented by _1_-_yMg_y)O_3, x, y, and m in the above formula each have a molar ratio of 0.3≦x≦0.5 0.001≦y≦ 0.020 0.98≦m≦1.02, and when the main component is 100 parts by weight, Mn as a subcomponent is 0.01 to 2.
A non-reducible dielectric ceramic composition characterized by containing 0.00 parts by weight. (2) Compositional formula (Sr_1_-_xCa_x)_m(Ti
In a dielectric ceramic composition whose main component is a substance represented by _1_-_yMg_y)O_3, x, y, and m in the above formula each have a molar ratio of 0.3≦x≦0.5 0.001≦y≦ 0.020 0.98≦m≦1.02, and when the main component is 100 parts by weight, Mn as a subcomponent is 0.01 to 2.
2. The non-reducible dielectric ceramic composition according to claim 1, further comprising 3.00 parts by weight of SiO_2.