JPS6168371A - 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 (Field of Industrial Application) The present invention relates to a ceramic composition, particularly a ceramic composition suitable for multilayer ceramic capacitors, which has a high dielectric constant and can be sintered at a low temperature of 1000°C or less. (Prior Art) It is well known that dielectric ceramic compositions containing barium titanate (BaTiOs) as a main component have been widely put into practical use as conventional dielectric ceramic compositions used in multilayer ceramic capacitors. However, The main component of BaTjol is a high-temperature sintering temperature of 1,300 to 1,400°C, and when used in a multilayer capacitor, it is necessary to use materials that can withstand this sintering temperature as internal electrodes, such as expensive materials such as platinum and palladium. Therefore, in order to be able to use inexpensive metals such as silver and nickel A- as the main component, the sintering temperature of porcelain must be lowered. It is desired to make it as low as possible.90For this reason, Pb (Fe2/3W1/3)
Os −Pb (Fe1/2 Nb :I/2) Os
(Special Publication No. 55-34962) and (Sr -Pb)Tj
O, -Pb(MgL/2W1/2)Os(%gi4fI
There are proposals such as I352-21699).

The present inventors have developed a new porcelain composition PK different from these.
We proposed a two-component composition consisting of [Pb (Co 1/2W
L/2)Os], [PbTl0n)1-, if X is between 0.35 and 0.75, 10
It was revealed that the material can be sintered at low temperatures below 00°C, has a high dielectric constant, and exhibits good dielectric loss characteristics.

However, this two-component porcelain composition has a low resistivity;
90 (Object of the Invention) The object of the present invention is to provide a ceramic composition for multilayer capacitors that can be sintered at a low temperature of 1000°C or less, has a high dielectric constant, low dielectric loss, and high specific resistance. [Pb(Ca1/'2W1/2)O8] [Pb(Ca1/'2W1/2)O8]
A two-component porcelain composition consisting of PbTiOs) 1-8 [however, 0.35≦X≦0.75) K, Pb as a subcomponent
(Example) The present invention will be explained in detail with reference to Examples.□ Lead oxide (pbo) with a purity of 99% or more as a starting material.

Cobalt carbonate (CoCO3), tungsten oxide (W
) to titanium oxide (TiOt)y manganese carbonate (M
nCO5) and weigh it to a predetermined mixing ratio. Next, after wet mixing in a ball mill, the mixture was prefired at 750 to 775°C.

After that, it is further ground in a ball mill, and then dried.

Add organic binder and sieve to 0.7 ton/Ly.
Pressed with Ig. Diameter 16mm, thickness approximately 2mm
Four disks were prepared and sintered in air at 880°C to 1000°C for 1 hour. Silver electrodes were placed on the top and bottom surfaces of the sintered disk.
Baked at 0°C, frequency 1k with digital LCR meter
Hz.

The capacitance and dielectric loss (tan δ) were measured at a voltage of IVrms, the dielectric constant was calculated, and a voltage of 50 V was applied for 1 minute using a 90-meter ultra-6 resistance meter to measure the total insulation resistance and calculate the specific resistance.

In each case, four samples were measured at room temperature, and the average value was taken as the representative value. The relationship between the properties thus obtained and the blending ratio is shown in the following table.

Note: Those with a wooden mark attached to Na are compositions that are not included in the present invention.

As is clear from the results shown in the table, the present invention has p b (
c o 1/'2 w L/2 ) O3 and pb'rt
A two-component system KP b (Mn 1/'2 ”
1/'2) When Os' is added, the specific resistance (K) is significantly increased and the dielectric loss (tan δ) is improved.

Moreover, it has a high dielectric constant and can be sintered at low temperatures, making it an excellent material for use as a ceramic composition for multilayer capacitors.

If the compounding ratio X exceeds 0.75 t-, the 1111C point will deviate significantly from the practical temperature range, and if it is less than 0.35, the 1111C point will deviate greatly toward the high temperature side, resulting in a decrease in the dielectric constant at room temperature. Pb (Mn 1/2W1/2
) If the amount of Os added is less than 0.3 molti, the effect of improving specific resistance and dielectric loss (tan δ) is small. If it exceeds 5 mol%, the effect of improving dielectric loss will be reduced. In this example, carbonate was used as the compound for cobalt and I-bustard, but oxides, oxalates, and sulfates that decompose at high temperatures to form oxides were used. , hydroxide, etc. may also be used.

(Effect of the invention)

Claims (1)

[Claims] Cobalt-lead tungstate [Pb(Co1/2W1/
2) A composition consisting of [Pb(Co1/2)O_3]_x[PbTiO_3] and lead titanate [PbTiO_3]
O_3] When expressed as _1_-_x, x is 0.35≦
A porcelain composition characterized in that 0.3 mol% to 5 mol% of Pb(Mn1/2W1/2)O_3 is added as a subcomponent to a main component composition in the range of x≦0.75.