JPS5935129B2 - Method for manufacturing porcelain for dielectric resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ceramics for dielectric resonators, particularly BaO, SrO, M
This relates to a method for producing ceramics for dielectric resonators composed of gO and Nb2O5 components, which have a large dielectric constant (ε), a large no-load Q, and a high temperature stability of the resonant frequency (
The present invention aims to provide a method suitable for manufacturing dielectric ceramic for microwave use with excellent τf).

Conventionally, in the microwave region, dielectric materials have been applied to impedance matching of microwave circuits, dielectric resonators, and the like.

In recent years, especially as the integration technology of microwave circuits has progressed, there has been an active effort to use dielectric ceramics with high dielectric constant, low loss, and low cost to stabilize the frequency of oscillators and to miniaturize them. progress is being made. Conventionally, these dielectric materials include compositions based on BaO-TiO2, compositions in which some of them are replaced with other elements, and compositions in which TiO2 has a negative dielectric constant and a positive dielectric constant. In many cases, a composition is used in combination with a dielectric composition that exhibits temperature changes.

However, these have many practical problems, such as large dielectric loss, large variations in temperature change in dielectric constant, and too high stability of resonance frequency. The present invention is a method suitable for manufacturing porcelain that eliminates these drawbacks, and in a dielectric composition system composed of BaO-SrO-MgONb2O, 3(Bal-XSrx)0.M
This invention is based on the discovery that gO-YNb2O5 solid solution porcelain is an excellent material for dielectric microwave resonators.

Here, the method of the present invention is based on the general formula 3(BaSr)1-X
After pre-calcining a mixture of starting materials weighed out to give a dielectric composition represented by XO・MaO-YNb2O5 (0 x x 1, 0.5≦y≦1.5), It is characterized by compacting the powder and hot press sintering it in an oxidizing atmosphere.

According to this method, it is possible to obtain a ceramic having excellent dielectric constant, no-load Q, and temperature stability of resonance frequency.

Then, the calcination temperature was set at 1100°C to 1200°C, the calcination time was set at 2 to 10 hours, and the hot press temperature was set at 1200°C to 1200°C.
50℃, hot press pressure 100-300kg/d,
By setting the hot pressing time within the range of 1 to 5 hours, it is possible to obtain a very excellent ceramic for dielectric resonator. Hereinafter, the manufacturing method according to the present invention will be explained based on Examples.

First, BaCO3, SrCO3, MgO and Nb2O
The starting materials of , were weighed according to each composition as shown in the table below, and wet mixed in a ball mill equipped with an agate ball and lined with rubber.

This mixture was dried, calcined in air under the conditions shown in the table below, and then wet-pulverized in the ball mill. After drying the calcined powder, a small amount of water was added to it to make it uniform, and it was molded at a pressure of 700k9/CTL. The compact was placed in an alumina mold together with alumina powder, and hot press sintered in an oxygen atmosphere under the conditions shown in the table below. Then, the dimensions of each sample were determined to be approximately 5m7 in diameter!
l, thickness 2m7! l, and its resonant frequency (approximately 11G
The dielectric constant (ε) was measured from the diameter (Hz) and the diameter, and the no-load Q (Qu) was measured by the band reflection method.

The temperature stability (τf) of the resonant frequency was determined by placing a dielectric resonator made of each sample in a temperature bath and measuring the change in trap frequency as the temperature changed from -30°C to +70°C. The results are shown in the table below. For comparison, the results for samples made under conditions outside the scope of the present invention are also shown in the table below.

As is clear from the results in the table above, hot press sintering improves the dielectric constant, the no-load Q, and the temperature change in the resonant frequency.

Then, the calcination conditions were set to a temperature of 11000C to 1200C, 2
~10 hours, hot press sintering conditions at a temperature of 1200℃ ~
1250℃, pressure 100-300k9/(1-Jmo V11
When the heating time is set to 1 to 5 hours, porcelain with better characteristics can be obtained. The atmosphere for hot press sintering should not be reducing, but preferably oxidizing. In addition,
It has been confirmed that the magnetism obtained by the method of the present invention has a small dielectric loss even in the low frequency range and a small change in dielectric constant with temperature, so it is an excellent material for ceramic capacitors.

Claims (1)

[Claims] 1 General formula 3 (Ba_1_-_xSr_x)O.MgO
・After calcining a mixture of starting materials weighed out to give a dielectric composition represented by yNb_2O_5 (0<x<1, 0.5≦y≦1.5), the calcined powder is A method for producing porcelain for a dielectric resonator, characterized by forming it and hot-press sintering it in an oxidizing atmosphere. 2. A method for manufacturing dielectric resonator porcelain according to claim 1, characterized in that the preliminary firing is performed at a temperature within the range of 1100°C to 1200°C. 3. A method for manufacturing dielectric resonator porcelain according to claim 2, characterized in that preliminary firing is performed for 2 to 10 hours. 4. The method for manufacturing dielectric resonator porcelain according to claim 1, 2, or 3, characterized in that hot press sintering is performed at a temperature within the range of 1200°C to 1250°C. Method. 5. In the method for manufacturing dielectric resonator porcelain according to claim 4, hot press sintering is performed at a temperature of 100 to 300
A method characterized in that it is carried out under a pressure of kg/cm^2. 6. A method for manufacturing dielectric resonator porcelain according to claim 5, characterized in that hot press sintering is carried out for 1 to 5 hours.