JPH0515006B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a dielectric ceramic composition for a dielectric resonator having a resonance frequency of 10-odd GHz. [Prior Art] A dielectric resonator with a resonant frequency of 10-odd GHz has an excellent no-load Q of about 10,000. The dielectric of this conventional dielectric resonator contains Ba・[Zn _1/3
A dielectric ceramic composition expressed by the composition formula Ta _2/3 .[Zn _1/3 Nb _2/3 ] ₁ /3.O ₃ was used. [Problems to be Solved by the Invention] The conventional dielectric ceramic compositions described above are expensive. The reason for this is that the firing temperature during the manufacturing process is approximately
Because the temperature is as high as 1,600℃, equipment costs for the kiln, its repair costs, and thermal energy costs increase.
This is because these increase manufacturing costs.
Therefore, there is a need for a dielectric ceramic composition that can be fired at lower temperatures. This invention was devised based on the above-mentioned demand, and provides a dielectric ceramic composition that is cheaper than conventional compositions. [Means for Solving the Problems] The dielectric ceramic composition of the present invention that achieves the above object has Ba.[Mg _(x) Co _{(1-x ) 1/3 ] x)} 〕 _2/
The main component is a composite perovskite in which x in the composition formula expressed _{by 3.O3 is} in the range of 0.3 to 0.9, and this 100
It contains 0.01 to 0.5 parts by weight of one or more components from the group Al ₂ O ₃ , Cr ₂ O ₃ , Y ₂ O ₃ and Mn ₂ O ₃ based on the weight part. [Example] Next, the value of x in the above composition formula is 0.5.
Ba・(Mg _0.5 Co _0.5 ) _1/3・(Ta _0.5 Nb _0.5 ) _2/3・O ₃ components are
A method for producing a dielectric ceramic composition containing 100 parts by weight and 0.1 parts by weight of Cr ₂ O ₃ will be described. First, 98.67 g of BaCO ₃ powder (equivalent to 0.500 mol),
MgO powder 3.36g (equivalent to 0.083 mol), CoO powder
6.22g (equivalent to 0.083 moles), 36.18g of Ta ₂ O ₅ powder
(equivalent to 0.083 mol), 22.06 g of Nb ₂ O ₅ powder (equivalent to 0.083 mol) and 0.167 g of Cr ₂ O ₃ powder (equivalent to the above BaCO ₃
Based on 100 parts by weight of the total amount of components from Nb ₂ O ₅ to
(equivalent to 0.1 part by weight) was weighed. This weighed powder was placed in a ball mill with pure water and wet mixed for 24 hours. The mixture thus obtained was dehydrated and dried at a temperature of 150°C for 5 hours, and then calcined at a temperature of 1100°C for 2 hours. Next, the calcined product was ground in a ball mill. Add polyvinyl alcohol to this crushed material.
3.0g was added, mixed using a grinder, and granulated by passing through a 60-mesh sieve. 0.66 of these granules
g was placed in a mold and a pressure of 3 tons/cm ² was applied. By repeating this pressure molding, a diameter of 7.0mmφ,
We made 20 disks with a thickness of 3.5 mm. These disks were then fired at a temperature of 1,370°C for 4 hours to a diameter of approx.
A dielectric ceramic disk of 6.0 mm and approximately 3.1 mm in thickness was obtained. Lap polish both sides of these dielectric porcelain discs,
Sample 17 was obtained by setting the thickness t to 3.00 mm. Next, a test method and results for measuring the relative dielectric constant ε at a temperature of 25° C. and the no-load Q of a dielectric resonator using the sample 17 as a dielectric will be explained. First, after measuring the diameter D of the aforementioned sample 17 with a micrometer, using a measurement system consisting of an 8620A sweep oscillator, an 8410A network analyzer, an 8743A test unit, and a computer manufactured by Yokogawa Heuretsu Patscard Co., Ltd. The relative permittivity ε and the no-load Q were measured. The above test unit includes two metal end plates (diameter 24 mm, thickness 3 mm) for electrodes of the dielectric resonator. First, the sample 3 is sandwiched between these metal end plates, and the dielectric resonator is configured. Next, the resonant frequency ₀ of this resonator and the insertion loss dB at resonance are measured. And the measured value of insertion loss dB at this resonance,
By inputting the sample 17+++D and the thickness t, which were actually measured in advance, into a computer, the dielectric constant ε and the unloaded Q of the dielectric resonator under test are respectively calculated, and the results are output. The relative dielectric constant ε determined in the above measurement system is determined by πD,
Resonance wavelength λ ₀ =C/f ₀ , propagation wavelength λg = 2t, Bessel function of the second kind v ² = (πD/λ ₀ ) [(λ ₀ /λg) ² −1],
The Betzel function of the first kind u ² is measured or calculated, and is determined from these values using the formula ε=(λ ₀ /πD) ² (u ² +v ² )+1. Also, the no-load Q is calculated as follows according to the computer program: load Q _L = f ₀ / f ₂ −
f ₁ (power width at half maximum) and a _t =10 ^−ILo/20 are obtained, and from these values, it is obtained using the arithmetic expression Q=Q _L /1− _at . The average value of the dielectric constant ε of the 20 samples determined as described above is 29.8, the maximum value is 29.5, and the minimum value is
It was 30.2. Furthermore, the average value of the unloaded Q of the 20 samples was 12,000, the maximum value was 13,600, and the minimum value was 11,200. These average values are calculated as the value of x in the above composition formula,
It is shown in the column of sample number 17 in the table below along with the firing temperature FT. Furthermore, sample 1 other than sample number 17 in the table below
Regarding the dielectric ceramic compositions Nos. 16 and 18 through 24, test dielectric resonators were made in the same manner as for Sample 17 described above, except that the firing temperature FT was slightly different depending on each composition. The characteristics of each resonator were determined using the same method as described above. The average values of these properties and the firing temperature FT are shown in the relevant columns of the table below.

【table】

〔Effect of the invention〕

As explained above, the dielectric ceramic composition of the present invention can obtain properties almost equivalent to those of conventional compositions, and can lower the firing temperature FT during the manufacturing process to 1370-1400°C. Equipment such as firing furnaces,
In terms of thermal energy for firing, etc., a dielectric ceramic composition can be obtained that is cheaper than conventional dielectric ceramic compositions. Specifically, the cost is expected to be reduced by about 15% compared to conventional dielectric ceramic compositions that require a firing temperature FT of 1600°C for sintering.

Claims (1)

[Claims] 1 Ba・[Mg _(x) Co _(1-x )] _1/3・[Ta _(x) Nb _(1-x) ] _2/3・
100 parts by weight of a component whose compositional formula represented by O ₃ has x in the range of 0.3 to 0.9, Al ₂ O ₃ , Cr ₂ O ₃ , Y ₂ O ₃ ,
One or more components of the Mn ₂ O ₃ group are 0.01 to 0.5
A dielectric ceramic composition consisting of parts by weight.