JPH08167324A - Dielectric porcelain composition - Google Patents

Abstract

PURPOSE: To provide a material suitable for a dielectric resonator and the like by containing glass powder composed of specified oxides, GeO2 and Li2 O of respective specified percentages by weight as accessory constituents in a composition whose main constituent is expressed by a formula. CONSTITUTION: The contents of accessory constituents, glass powder composed of PbO, ZnO and B2 O3 , GeO2 and Li2 O, (a), (b) and (c) (percentages by weight against a main constituent) are set to 1<=a<=25, 0.5<=b<=10, 0.04<=c<=4 respectively. Barium carbonate, titanium oxide, neodymium oxide, samarium oxide and bismuth oxide of respective predetermined amounts are wet-blended, are dried and are ground. Thereafter, the same is calcined in the air at 1000 to 1300 deg.C for 1 to 5 hours. After the glass powder, the GeO2 , and Li2 CO3 are added to and are blended with this calcined powder and further the same is uniformly blended with an organic binder, the same is dried, is ground and is press-formed. The same is burnt in an oxygen containing gas atmosphere at 850 to 1100 deg.C so as to obtain a porcelain composition which has a high dielectric constant, a large no-load Q and small temperature change of a resonant frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition suitable as a material for a dielectric resonator or the like.

[0002]

2. Description of the Related Art In recent years, with the integration of microwave circuits, a compact and high-performance dielectric resonator has been demanded. The dielectric ceramic composition used for such a dielectric resonator is required to have characteristics such as a large relative permittivity ε _r , a large unloaded Q, and a small temperature coefficient τ _f of the resonance frequency. Has been done.

As such a dielectric ceramic composition, Ba
Proposed O-TiO ₂ —Nd ₂ O ₃ based dielectric ceramic composition [Ber. Dt. Keram. Ges., 55 (1978) Nr. 7;
-35406 JP], or BaO-TiO ₂ -N
A d ₂ O ₃ -Bi ₂ O ₃ system (Japanese Patent Laid-Open No. 62-72558) has been proposed.

Recently, a laminated chip capacitor, a laminated dielectric resonator, etc. in which dielectric ceramic compositions are laminated have been developed, and the ceramic composition and internal electrodes are laminated by simultaneous firing. However, since the firing temperature of the dielectric ceramic composition is as high as 1300 ° C. to 1400 ° C., it is difficult to perform simultaneous firing with the internal electrodes, and in order to form a laminated structure, it can withstand high temperatures as an electrode material. It has been limited to materials such as palladium (Pd) and platinum (Pt). Therefore, inexpensive silver (Ag), silver-palladium (Ag-Pd), and copper (Cu) are used as the electrode material at 1200 ° C.
There is a demand for a dielectric ceramic composition that can be co-fired at the following low temperatures.

[0005]

It is an object of the present invention to have excellent characteristics as a material for a dielectric resonator or the like, in particular to have a high dielectric constant, a large no-load Q, and a small change in resonance frequency with temperature.
Moreover, it is to provide a dielectric ceramic composition having good sinterability even when fired at a low temperature.

[0006]

Means for Solving the problems] The present invention is a main component composition _{formula, xBaO-yTiO 2 -zNd 2 O} 3 -tSm 2
O ₃ -wBi ₂ O ₃ (wherein 0.1 ≦ x ≦ 0.2, 0.
5 ≦ y ≦ 0.8, 0.01 ≦ z ≦ 0.2, 0 ≦ t ≦ 0.
2, 0.005 <w <0.05, x + y + z + t + w =
It is 1. ) Represented by barium, titanium, neodymium,
A dielectric ceramic composition composed of samarium, bismuth, and oxygen, and PbO, ZnO, and B as auxiliary components.
Glass powder composed of ₂ O ₃ and GeO ₂ and Li ₂ O, the content a (% by weight) of the accessory glass powder with respect to the main component is 1 ≦ a ≦ 25, and the content b of GeO ₂ is b (weight). %) 0.5 ≦ b ≦ 10 and the Li ₂ O content c (% by weight) is 0.04 ≦ c ≦ 4.

According to the invention, the composition formula xBaO-yTi
The dielectric ceramic composition represented by O ₂ -zNd ₂ O ₃ -tSm ₂ O ₃ -wBi ₂ O ₃ contains PbO and Zn as auxiliary components.
Glass powder composed of O and B ₂ O ₃ and G
By containing eO ₂ and Li ₂ O, it is possible to obtain a dielectric ceramic composition which can be sintered at a low temperature, has a high dielectric constant, has a large unloaded Q, and has a small temperature change in resonance frequency. .

In the present invention, when the molar fraction of BaO is excessively large, resonance does not occur, and when it is excessively small, the dielectric constant and the no-load Q become small. When the mole fraction of TiO ₂ is too large, the temperature coefficient of the resonance frequency becomes large, and when it is too small, the dielectric constant becomes small. When the mole fraction of Nd ₂ O ₃ is excessively large, the dielectric constant and unloaded Q become small, and when it is excessively small,
The temperature coefficient of the resonance frequency becomes large. When the mole fraction of Sm ₂ O ₃ is excessively large, the dielectric constant and unloaded Q become small. When the mole fraction of Bi ₂ O ₃ is excessively large, the dielectric constant and the no-load Q become small, and when it is excessively small, the temperature coefficient of the resonance frequency becomes large.

Further, in the present invention, the content a (% by weight) of the glass powder composed of the subcomponents PbO, ZnO and B ₂ O ₃ and the content b (% by weight) of GeO ₂ with respect to the main component are excessive. When it is large, the no-load Q is small, and when the content c (wt%) of Li ₂ O is too large, resonance does not occur. Further, glass powder composed of PbO, ZnO and B ₂ O ₃ and GeO ₂
When the content b (% by weight) is too small or zero, low temperature firing at 1200 ° C. or lower becomes difficult. Li ₂
By including O, the sintering temperature is further lowered,
The Ag internal electrodes can be easily formed. Therefore,
The content a (% by weight) of the glass powder composed of the subcomponents PbO, ZnO and B ₂ O _3, the content b (% by weight) of GeO _{2 and} the content c (% by weight) of Li ₂ O are within the above range. Is set to. Subcomponents PbO, ZnO and B
_{In a} glass powder composed of ₂ O ₃ , PbO, Z
Although the composition ratio of nO and B ₂ O ₃ is not particularly limited,
When the content of ZnO is excessively large, the softening point of the glass rises and low-temperature firing becomes difficult. Therefore, the content of ZnO in the glass powder is preferably 50% by weight or less.

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, titanium oxide, neodymium oxide, samarium oxide, and bismuth oxide are wet-mixed in predetermined amounts with a solvent such as water or alcohol. Then, after removing water, alcohol, etc., the product is pulverized and placed under an oxygen-containing gas atmosphere (for example, an air atmosphere) to obtain 1
Calcination is performed at 000 to 1300 ° C. for about 1 to 5 hours. A glass powder composed of the calcined powder thus obtained and the subcomponents PbO, ZnO and B ₂ O ₃ , GeO ₂ , Li
₂ CO ₃ is wet mixed and pulverized with a solvent such as alcohol. Then, after removing water, alcohol, etc., they are mixed with an organic binder such as polyvinyl alcohol to be homogenized, dried, crushed and pressure molded (pressure 100 to 1000 K).
g / cm ² ). The dielectric ceramic composition represented by the above composition formula is obtained by firing the obtained molded product in an oxygen-containing gas atmosphere such as air at 850 ° C to 1100 ° C.

The dielectric ceramic composition thus obtained is processed into a suitable shape and size as required, or by sheet molding by a doctor blade method or the like and lamination by a sheet and an electrode. It can be used as a material for a dielectric resonator, a dielectric substrate, a laminated element, and the like.

Barium, titanium, neodymium, summer
Lithium, bismuth, lead, zinc, boron, germanium,
As a raw material of lithium, BaCO₃, TiO₂, Nd
₂O ₃, Sm₂O₃, Bi₂O₃, PbO, ZnO, B
₂O₃, GeO₂, Li₂CO₃Besides, oxidation during firing
It is possible to use a nitrate, a hydroxide, or the like that is a substance.

[0013]

EXAMPLES The present invention will be described more specifically by showing Examples and Comparative Examples below. Example 1 barium carbonate powder (BaCO ₃₎ 0.13 moles of titanium oxide powder (TiO ₂₎ 0.69 mol of neodymium oxide紛末(Nd ₂ O ₃₎ 0.16 mol, bismuth oxide紛末(Bi
0.02 mol of ₂ O ₃ ) was put in a ball mill together with ethanol and wet mixed for 12 hours. After desolvating the solution, crush it,
It was calcined at 1250 ° C in an air atmosphere. In addition, lead oxide powder (PbO) 84 wt%, zinc oxide powder (ZnO) 7 wt
% And boron oxide powder (B ₂ O ₃ ) 9 wt%, a glass powder A was prepared by a conventional method. The PbO to calcine obtained above, the glass powder A2wt% and germanium oxide powder (GeO ₂₎ 3wt% and lithium carbonate powder made from ZnO and _{B 2 O 3 (Li 2 CO} 3) 1wt% (Li 2 0.4 wt in O conversion
% And added to a ball mill with ethanol and wet mixed for 48 hours. After desolvating the solution, it was pulverized, an appropriate amount of polyvinyl alcohol solution was added to the pulverized product, and the pulverized product was dried.

The porcelain composition thus obtained has a diameter of 7 mm.
After processing into a size of φ and a thickness of about 3 mmt, measurement was performed by the dielectric resonance method, and the unloaded Q at the resonance frequency (3 to 6 GHz), the relative permittivity, and the temperature coefficient of the resonance frequency were obtained. The results are shown in Table 2.

Examples 2 to 21 and Comparative Examples 1 to 16 Barium carbonate, titanium oxide, neodymium oxide of Example 1
The mixing ratio of samarium oxide and bismuth oxide and the kind of glass powder composed of PbO, ZnO and B ₂ O ₃ which are the accessory components (glass powder B: PbO 80 wt%,
ZnO 10 wt%, B ₂ O ₃ 10 wt%) and the amounts of the subcomponents added were changed as shown in Table 1, and a dielectric ceramic composition was produced in the same manner as in Example 1, and the characteristics were measured. The results are shown in Table 2.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

According to the present invention, it is possible to provide a dielectric ceramic composition having a large relative permittivity ε _r , a large unloaded Q value, and a small temperature coefficient τ _f of the resonance frequency. In addition, low temperature sintering is possible, and Ag, Ag-P
It is possible to provide a dielectric porcelain composition which can be laminated by using d, Cu or the like as an internal electrode.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01P 7/10 (72) Inventor Shinichi Ishihii 5 Ube Industries Ltd., 5 1978, Kogushi, Ube City, Yamaguchi Prefecture Company Ube Institute

Claims (1)

[Claims] 1. The main component is a composition formula, xBaO-yTiO.
_{2 -zNd 2 O 3 -tSm 2 O} 3 -wBi 2 O 3 ( where, 0.1 ≦ x ≦ 0.2,0.5 ≦ y ≦ 0.8,0.0
1 ≦ z ≦ 0.2, 0 ≦ t ≦ 0.2, 0.005 <w <
0.05 and x + y + z + t + w = 1. ) Is a dielectric porcelain composition consisting of barium, titanium, neodymium, samarium, bismuth and oxygen, and is a glass powder composed of PbO, ZnO and B ₂ O ₃ as auxiliary components, and GeO ₂ and Li ₂ Contains O,
Content a of glass powder as an accessory component to the main component (% by weight)
Is 1 ≦ a ≦ 25, and the GeO ₂ content b (% by weight) is 0.
5. Dielectric ceramic composition, wherein 5 ≦ b ≦ 10 and a Li ₂ O content c (% by weight) is 0.04 ≦ c ≦ 4.