JPH0721837A - Dielectric ceramic composition - Google Patents

Abstract

PURPOSE:To provide a dielectric ceramic composition with high dielectric constant, high Q, and good stability of tauf. CONSTITUTION:A dielectric ceramic composition consists of mainly a composition having a formula x(Ba1-LSrL)O.y(Zn1-MMgM)O.Z[(Nb1-NSbN)2O5] (wherein 0.49<x<0.51, 0.16<y<0.18, 0.31<z<0.35, x+y+Z=1, 0.4<L<0.18, 0<M<1.0, 0<N<0.20) and consisting of barium, strontium, zinc, magnesium, niobium, antimony, and oxygen, and to the main component at least one of Cr2O3, MnO and CoO as auxiliary components is added at 0-2wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a main component composed of barium, strontium, zinc, magnesium, niobium, antimony and oxygen suitable as a dielectric resonator material, and Cr ₂ O ₃ , MnO and CoO as subcomponents. The present invention relates to a dielectric ceramic composition obtained by adding at least one kind in an amount of 0 to 2 wt%. The dielectric ceramic composition of the present invention can be used, for example, in a microwave IC in addition to the dielectric resonator material.
It can also be used as a substrate, dielectric adjusting rod, etc.

[0002]

2. Description of the Related Art In recent years, with the integration of microwave circuits, a compact and high-performance dielectric resonator is required. The dielectric ceramic composition used for such a dielectric resonator has a large relative permittivity ε _r , stability of the temperature coefficient τ _f of the resonance frequency, and linearity of the temperature characteristic of the resonance frequency. Characteristics such as excellent and large no-load Q are required.

As such a dielectric ceramic composition,
It is known that TiO ₂ , BaO-TiO ₂ or the like is the main component, but it is difficult to put it into practical use because of its large temperature coefficient and large dielectric loss in the microwave band.

Further, xBaO-yZnO-zNb₂O_Five
Of the dielectric ceramic composition of JP-A-53-35
No. 453) or (Ba_1-XSr_X) O ・ ZnO ・ y
Nb ₂O_FiveProposal of Dielectric Porcelain Composition (Japanese Patent Publication No. 59-2
3045), but both are sufficiently large ε_rAnd Q
No value is available. Furthermore, Ba (Mg_1/3Ta_2/3)
O₃System, Ba (Zn_1/3Ta_2/3) O₃System, Ba (Zn
_1/3Nb_2/3) O₃Have a perovskite structure such as a system
Dielectric porcelain compositions are also known.
Resonance in 0.1 to 4 GHz band due to small rate
The problem is that the vessels become too big.

[0005]

An object of the present invention is to provide a dielectric ceramic composition suitable as a dielectric resonator material, particularly as a dielectric resonator material used in the 0.1 to 5 GHz band. Another object of the present invention is to provide a dielectric ceramic composition having a high dielectric constant, a large Q, and a good stability of ε _r .

[0006]

Among the many constituent elements used in dielectric porcelain compositions, the inventors have selected from the combination of barium, strontium, zinc, magnesium, niobium, antimony and oxygen. It was found that the above object can be achieved by the following specific porcelain composition. The present invention provides a compositional formula x (Ba _1-L Sr _L ) O.y (Zn _1-M
Mg _M ) O · z [(Nb _1-N Sb _N ) ₂ O ₅ ] (wherein
0.49 <x <0.51, 0.16 <y <0.18,
0.31 <z <0.35, x + y + z = 1,0.4 <L
<0.8, 0 <M <1.0, 0 <N <0.20. ) To barium, strontium, zinc, magnesium, niobium, antimony, and oxygen, which are main components, and Cr ₂ O ₃ , MnO, and Co as secondary components.
The present invention relates to a dielectric ceramic composition obtained by adding 0 to 2 wt% of at least one of O.

The dielectric ceramic composition of the present invention has a relative dielectric constant of
Since it is large, the resonator can be downsized and the unloaded Q is also large.
Become Furthermore, the temperature coefficient τ of the resonance frequency_fIs small. Book
In the invention, the molar fraction of SrO is larger than 0.8.
, Or less than 0.4, the temperature coefficient of resonance frequency
τ_fTherefore, the molar fraction of SrO should be within the above range.
Limited. Moreover, when the molar fraction of MgO is 0, it is non-negative.
If the load Q is small and it is 1, the dielectric constant is small, so
The MgO mole fraction is limited to the above range. Also, x,
The reason for limiting the range of y and z as described above is this range
In any case outside, the no-load Q becomes smaller, or
This is because the dielectric constant becomes small. Furthermore Sb₂O_FiveMo
If the load fraction is larger than 0.2, the no-load Q will be small.
And Sb₂O _FiveThe mole fraction of is limited to the above range. Well
And Cr₂O₃, At least one of MnO and CoO
If the added amount of each type is greater than 2 wt%, the no-load Q is small
Therefore, the amount of the subcomponent added is limited to the above range.

An example of a suitable method for producing the dielectric ceramic composition of the present invention will be described below. Starting materials of barium carbonate, strontium carbonate, zinc oxide, magnesium oxide, niobium oxide, and antimony oxide are wet-mixed in predetermined amounts with a solvent such as water or alcohol. Then, after removing water, alcohol, etc., it is pulverized and calcined in an oxygen-containing gas atmosphere (for example, an air atmosphere) at 1100 to 1300 ° C. for about 2 hours. The calcined product thus formed is crushed, mixed with an organic binder such as polyvinyl alcohol to be homogenized, dried and crushed, and pressure-molded (pressure 100 to 10).
00 Kg / cm ² ). Then, the molded product is fired at 1500 to 1650 ° C. in an oxygen-containing gas atmosphere such as air to obtain a dielectric ceramic composition represented by the above composition formula.

The dielectric ceramic composition thus obtained is processed as it is or, if necessary, into an appropriate shape and size to obtain a dielectric resonator, a dielectric substrate for microwave IC, a dielectric adjusting rod. Etc., and particularly when used as a dielectric band resonator used in the 0.1 to 5 GHz band, excellent effects are exhibited.

Barium, strontium, zinc,
As a raw material for magnesium, niobium and antimony, B is used.
aCO₃, SrCO₃, ZnO, MgO, Nb₂O_Five,
Sb ₂O_FiveIn addition to, carbonates and water that become oxides during firing
Oxides and the like can be used. Also, Cr₂O₃,
For MnO and CoO as well, carbonic acid that becomes an oxide during firing
Salts, hydroxides and the like can be used.

[0011]

EXAMPLES The present invention will be described in more detail below with reference to Examples.
Explained. Example 1 Barium carbonate (BaCO₃) Powder, strontium carbonate
(SrCO₃) Powder, Zinc Oxide (ZnO) Powder, Matric Oxide
Gnesium (MgO) powder, niobium oxide (Nb ₂O_Five)
Powder, antimony oxide (Sb₂O_Five) Powder the ethanol
It was put in a ball mill together with and wet-mixed for 12 hours. this
Remove the mixture from the ball mill and remove the solvent ethanol.
Evaporate and crush with a mashing machine for 1 hour to give 0.5 (Ba_0.4
Sr_0.6) ・ 0.167 (Zn_0.6Mg_0.4) ・ 0.3
33 [(Nb_0.98Sb_0.02)₂O _Five] To obtain
It was

Then, an appropriate amount of polyvinyl alcohol was added to the calcined powder.
After adding the rucor solution and mixing it uniformly, the diameter is 15 mm.
Φ, 5.5mm thick pellets are molded and air atmosphere
And the dielectric magnet of the present invention by firing and sintering at 1560 ° C. for 2 hours.
A vessel composition was obtained. The porcelain composition thus obtained is
After cutting to size, measure by the dielectric resonance method,
Swing frequency f₀Unloaded Q and ratio at (4-6 GHz)
Dielectric constant ε _rI asked. In addition, the temperature dependence of the resonance frequency
Therefore, the temperature is measured in the range of -40 to 50 ° C
_fI asked. The results are shown in Table 2.

Examples 2 to 19 The mixing ratio of barium carbonate, strontium carbonate, zinc oxide, magnesium oxide, niobium oxide and antimony oxide of Example 1 was changed as shown in Table 1, or Cr ₂ O ₃ was added as a subcomponent. , MnO and CoO were added, and a dielectric ceramic composition was manufactured in the same manner as in Example 1, and the characteristics were measured in the same manner as in Example 1. The results are shown in Table 2. Those marked with * in the table are comparative examples outside the scope of the present invention. Moreover, Examples 1 to 7 are reference examples.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

According to the present invention, a dielectric ceramic composition having a high dielectric constant, a large Q, and a good stability of τ _f can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Mitani 5 1978, Kogushi, Ube City, Ube City, Yamaguchi Prefecture Ube Industries Ltd. Inorganic Materials Research Laboratory

Claims (1)

[Claims] 1. A composition formula x (Ba _1-L Sr _L ) O.y (Zn
_1-M Mg _M ) O · z [(Nb _1-N Sb _N ) ₂ O ₅ ] (wherein 0.49 <x <0.51, 0.16 <y <0.1
8, 0.31 <z <0.35, x + y + z = 1,0.4
<L <0.8, 0 <M <1.0, 0 <N <0.20. ) Barium, strontium, zinc,
Cr ₂ O ₃ , MnO, and C as secondary components to the main component consisting of magnesium, niobium, antimony, and oxygen.
A dielectric ceramic composition obtained by adding 0 to 2 wt% of at least one of oO.