JPS63116305A - Dielectric magnetic composition - Google Patents

Abstract

(57) [Abstract] 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 temperature-compensating dielectric ceramic composition that can be fired at a temperature of 1150° C. or lower.

Conventional Temperature Compensating Materials Used in Ceramic Capacitors include MgO-CaO-TiO2-based materials (e.g., JP-A-48-86097) and La203-Ti02-based materials (e.g., JP-A-Sho. 51-A). 30400), but these materials require a firing temperature of 1250~
Since the temperature is as high as 1,400° C., when used in a multilayer ceramic capacitor, expensive platinum, palladium, or dium electrodes are required as internal electrodes.

On the other hand, among high dielectric constant materials, it has recently been discovered that composite perovskite materials mainly composed of PbO exhibit low firing temperatures of around 1000°C and excellent dielectric properties.
Many compositions have been proposed because cheaper silver thread electrodes can be used as electrodes. For example, JP-A-59-
PbTi03-Pb disclosed in Publication No. 57954
(Ni1z2W!, 2) In the 03 series, the firing temperature is 900
~1000°C and a dielectric constant of 1200 to 7500.

Problems to be Solved by the Invention Conventionally used temperature-compensating ceramic capacitor materials require expensive electrodes due to the high firing temperature.
In order to use cheaper silver thread electrodes, a dielectric material that can be fired at a temperature of 1150° C. or lower is desired. PbO
Composite perovskite materials, which are mainly composed of , have a large change in dielectric constant with temperature, and there are no known materials that can be used for temperature compensation capacitors.

In view of the current situation, an object of the present invention is to provide a dielectric ceramic composition having a low firing temperature and a small rate of temperature change.

Means for solving the problem Pb in the PbTi, □(Ni1.z Wl/2 ) 03 solid solution is partially replaced with Ca.

By substituting a part of -x Pb in the functional PbTi (N1xz2W1/2) 03 solid solution with Ca, it is possible to obtain characteristics for temperature compensation without impairing low-temperature sinterability.

Examples As starting materials, chemically high purity PbO, CaC0a
, TE01. After correcting the purity of NiO and WO3, predetermined amounts were weighed and mixed in a ball mill for 17 hours using agate boulders and pure water as a solvent. This is filtered by suction to remove most of the moisture, dried, and then thoroughly crushed using a Raikai machine.
Add % moisture and molding pressure 500 m/cnf to diameter 6
It was molded into a cylindrical shape with a length of 0m+n and a height of about 50w*. Place this in an aluminum crucible, cover with a similar lid, and heat at 750°C to 88°C.
It was calcined at 0°C for 2 hours. Next, the calcined product was roughly crushed in an alumina mortar, and further crushed in a ball mill using agate cobblestones and pure water as a solvent for 17 hours, filtered under suction to remove most of the moisture, and then dried. After repeating the above calcining, crushing, and drying process several times, add 6wt of polyvinyl alcohol to this powder.
% aqueous solution was added at 6 wt% of the powder amount, and the mixture was granulated through a 32-mesh sieve, and molded into a cylindrical shape with a diameter of 13 mm and a height of about 5 nwg at a molding pressure of 1000 kg/ci. The molded product was heated to 700°C in air and held for 1 hour to burn out the polyvinyl alcohol content. After cooling, it was transferred to a Magnesia porcelain container, covered with a similar lid, and heated to a specified temperature in air at 400°C/ 1] Raise the temperature at r and hold for 2 hours 4
The temperature was lowered at a rate of 00°C/hr.

The fired product was cut into a disk shape with a thickness of 1 m, and both sides were coated with Cr-Au.
, dielectric constant, and Q, IMHz.

Measurements were made under an electric field of IV/+n+a. Moreover, the resistivity is 1 after applying a voltage of 1 k'V/mm at 20 °C.
Calculated from minute values. The firing temperature was set at the temperature at which the density of the fired product was the highest.

Table 1 shows the composition range of the present invention, peripheral composition components, firing temperature, dielectric constant, temperature change rate of Q1 dielectric constant, and resistivity.

(Margins below) For compositions outside the scope of the invention, samples marked with * in No. of Table 1 were cited as examples, but when Caff1 exceeds 0.6, the optimum firing temperature exceeds 1150°C and 0° If the Ti amount is less than 2, the rate of change in dielectric constant will be 11,000 pp/° C. or more, or if the Ti amount is less than 0.5, Q will be less than 100.0.

Effects of the Invention According to the dielectric ceramic composition of the present invention, a temperature change rate of dielectric constant of 11,000 pp/'C or less and a Q of 1,000 or more can be obtained, and furthermore, since it can be fired at a temperature of 1,150°C or less, lamination is possible. Ag-Pd as internal electrode of capacitor element
It is of great industrial value because it allows the use of similar materials and enables the realization of inexpensive multilayer capacitors.

Claims (1)

[Claims] (PbCa)TiO_3 and (PbCa)(Ni_1
_/_2W_1_/_2)O_3, Pb_1_-_xCa_xTi_1_-_y(Ni_
When expressed as 1_/_2W_1_/_2)_yO_3,
A dielectric ceramic composition characterized in that x and y are in the ranges of 0.3≦x≦0.6 and 0.05≦y≦0.4, respectively.