JPH055778B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing a ceramic material for a dielectric resonator, and in particular to _a method for manufacturing a ceramic material for a dielectric resonator.
2/3) It relates to a manufacturing method that can stably obtain high Q in a short firing time in O ₃ -based materials. Conventional Technology In recent years, with the advancement of technology for high-frequency circuits that handle microwaves and millimeter waves (hereinafter collectively referred to as microwaves) with wavelengths of several centimeters or less, there has been active progress in miniaturizing these circuits. It is being Until now, this high-frequency circuit used cavity resonators,
Antennas and the like have been used, but their size is comparable to the wavelength of microwaves, which has been an obstacle to miniaturization. To solve this problem, a method has been used to shorten the wavelength itself by using dielectric ceramics with a high dielectric constant. Among these, Ba(Zn1/3Nb2/3)O ₃ −Ba
(Zn1/3Ta2/3)O3 _- based materials have a dielectric constant of about 30,
It is known that the value of unloaded Q at 12GHz reaches 14000 [J.Am.Ceram.Soc.vol66.421-423
(1983)]. Problem to be solved by the invention Ba(Zn1/3Nb2/3)O ₃ −Ba(Zn1/3Ta2/3)O ₃
As mentioned above, this material is an excellent material that exhibits a very high Q in the microwave region _.
In the method of simultaneously mixing predetermined amounts of ZnO, Nb ₂ O ₅ and Ta ₂ O ₅ and calcining them, a long firing time is required to obtain a high Q. For example, when using Ba(Zn1/3
Ta2/3) O ₃ , to get 14000 Q, 1350
There was a problem that it required about 120 hours of firing time at ℃. In view of such problems, the present invention
The purpose of the present invention is to provide a manufacturing method that can stably obtain a high Q in a short firing time in a Ba(Zn1/3Nb2/3)O ₃ -Ba(Zn1/3Ta2/3)O ₃ based material. Means for Solving the Problems As a technical means of the present invention to solve the above problems, as a result of examining various factors in the manufacturing method, we found that the Zn, Nb, and Ta components of the starting materials were It has been found that the above problems can be solved by performing a step of calcining and calcining this and the remaining components again. In other words, according to the manufacturing method claimed in the claims of the present invention, by first calcining the Zn, Nb, and Ta components, a ZnNb ₂ O ₆ -ZnTa ₂ O ₆ composite having a columbite structure is produced. Form the oxide first, and then
By reacting the Ba component, Ba(Zn1/3Nb
2/3) O ₃ -Ba(Zn1/3Ta2/3) In the O ₃ solid solution, the ordering of Zn, Nb, and Ta is promoted, and a high Q can be stably obtained in a short firing time. Example Starting materials include chemically highly purified BaCO ₃ ,
Nb ₂ O ₅ , Ta ₂ O ₅ , and ZnO were used. After correcting the purity of these, the predetermined amount was calculated. Next, among these, Nb ₂ O ₅ , Ta ₂ O ₅ , and ZnO were weighed and wet-mixed for 17 hours in a ball mill using agate cobblestones and pure water as a solvent. After drying, the mixture was granulated through a 32-mesh sieve, and calcined in air at a predetermined temperature of 750°C to 1250°C for 2 hours. calcined items and
BaCO ₃ was weighed again to a predetermined amount, and wet mixed with pure water using agate cobblestones in a ball mill for 17 hours. After drying, add 5wt% of pure water, pass through a 32-mesh sieve, and granulate it in a 50mmφ mold.
It was molded at a molding pressure of 500 Kgr/cm ² and calcined at 1100° C. for 2 hours in an alumina crucible. The calcined product is coarsely crushed into rice-grain-sized pieces using an alumina mortar and then ball milled using agate boulders and pure water as a solvent.
Grind for 20 hours. After drying this, 8wt% of 3wt% polyvinyl alcohol solution was added to make it homogeneous, and then it was granulated through a 32 mesh sieve.
It was molded using a φ mold at a molding pressure of 1000 Kgr/cm ² . The molded body was heated to burn out the binder at 700°C for 1 hour in air, and then transferred to a magnesia container and heated to a specified temperature at a heating rate of 200°C/hr.
After holding for a predetermined time, the temperature was lowered. The dielectric properties were measured by the dielectric resonator method, and the resonant frequency and no-load Q were determined. Resonance frequency is about 12G
It is Hz. Table 1 shows Ba(Zn1/3Nb2/3)O ₃ −Ba(Zn1/3Ta
2/3) In the O ₃ system, the temperature at which ZnO, Nb ₂ O ₅ and Ta ₂ O ₅ are first mixed and calcined, and the no-load Q when the firing temperature is 1350°C and the firing time is 30 hours are shown. Samples marked with * in the table are comparative examples outside the scope of the claims. Also, in this example, as a starting material
Although ZnO, Nb ₂ O ₅ and Ta ₂ O ₅ were used, similar effects can be expected by using other hydroxides, carbonic acid, etc.

【table】

[Table] Effect of the invention As described above, according to the manufacturing method claimed in the present invention, Ba(Zn1/3Nb2/3)O ₃ −Ba(Zn1/3Ta
2/3) It is an excellent method for producing ceramic materials for dielectric resonators that is highly mass-producible because it can stably obtain a high Q with a short firing time in O ₃ -based materials.

Claims (1)

[Claims] 1 Ba(Zn1/3Nb2/3)O ₃ −Ba(Zn1/3Ta2/3)
In the manufacturing process of O3 _- based ceramic materials for dielectric resonators, the Zn, Nb, and Ta components of the starting materials are heated at temperatures above 750°C.
A method for producing a ceramic material for a dielectric resonator, comprising the steps of calcining at 1250°C or lower, mixing this with a Ba component again, and calcining.