JP3291817B2 - Dielectric porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

[0003] BaO is used as such a dielectric porcelain composition.
Suggestions for -TiO ₂ -Nd ₂ O ₃ based dielectric ceramic composition [Ber.Dt.Keram.Ges.55 (1978) Nr.7; JP 60
No. 35406] or BaO-TiO ₂
—Nd ₂ O ₃ —Bi ₂ O ₃ system (Japanese Patent Application Laid-Open No. 62-72558)
And Japanese Patent Application Laid-Open No. Sho 62-100906).

[0004] Recently, multilayer chip capacitors, multilayer dielectric resonators, and the like in which a dielectric ceramic composition is laminated have been developed, and lamination by simultaneous firing of the ceramic composition and internal electrodes has been performed. However, since the firing temperature of the dielectric porcelain composition is as high as 1300 ° C. to 1400 ° C., it is difficult to perform simultaneous firing with an internal electrode. It was limited to materials such as palladium and platinum. Therefore, using inexpensive silver-palladium or copper as the electrode material,
The development of the following dielectric porcelain composition that can be co-fired at a low temperature is required.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide excellent characteristics as a dielectric material, in particular, a high dielectric constant, a large no-load Q, a small change in the resonance frequency with temperature, and when fired at a low temperature. Another object of the present invention is to provide a dielectric ceramic composition having good sinterability.

[0006]

According to the present invention, there is provided a compound represented by the following formula:
bismuth represented by i ₁₂ GeO _20, with respect to the main component consisting of germanium and oxygen, relates to a dielectric ceramic composition of SiO _2, characterized in that it contains 0.5 to 5.0 wt% as an auxiliary component.

According to the present invention, the constituent phase is Bi ₁₂ GeO ₂₀
Incorporation of a specific amount of SiO ₂ into the material can improve the disadvantages of the conventional dielectric ceramic composition,
By adding ₂ , the temperature coefficient τ _f of the resonance frequency can be shifted to the positive side.

An example of a preferred method for producing the dielectric ceramic composition of the present invention will be described below. The starting materials of bismuth oxide, germanium oxide and silicon oxide are wet-mixed in predetermined amounts with a solvent such as water or alcohol. Subsequently, after removing water, alcohol, and the like, the mixture is pulverized, and crushed under an oxygen-containing gas atmosphere (for example, an air atmosphere) at 650 to 750 ° C. for about 1 to 5 times.
Calcinate for about an hour. After pulverizing this calcined product, it is mixed with an organic binder such as polyvinyl alcohol to homogenize, dried, pulverized, and then pressure-formed (pressure 100 to 1000 k).
g / cm ² ). The obtained molded article is fired at 800 to 900 ° C. in an oxygen-containing gas atmosphere such as air to obtain the dielectric ceramic composition.

The dielectric porcelain composition can be processed as it is or as required in an appropriate shape and size, or formed into a sheet by a doctor blade method or the like and laminated by a sheet and an electrode to obtain a dielectric resonator, a microwave, or the like. It can be used as a material for a dielectric substrate for IC, a microwave laminated substrate, and the like.

Note that bismuth, germanium, and silicon
The raw material is Bi_TwoO_Three, GeO _Two, SiO_TwoEtc.
Use nitrates, hydroxides, etc. that become oxides during firing.
Can be

[0011]

The present invention will be described in more detail with reference to the following examples.
explain. Example 1 Bismuth oxide (Bi_TwoO_Three) Powder 0.857 mol, oxidation
Germanium (GeO _Two) 0.143 mol of powder and acid
Silicon oxide (SiO_Two) 0.5wt% of powder with ethanol
Into a ball mill and wet-mixed for 10 hours. Solvent d
The ethanol was evaporated and crushed for 1 hour with a crusher. Grinding
The material was calcined at 700 ° C. in an air atmosphere. Furthermore, eta
Place in a ball mill with knoll and wet mix for 10 hours
Was. After desolvating the solvent ethanol, powder for 1 hour with a mill
Crushed. An appropriate amount of polyvinyl alcohol solution
After adding and drying, pellets with a diameter of 12 mmφ and a thickness of 4 mmt
And baked at 850 ° C. for 2 hours in an air atmosphere.
The porcelain composition of Example 1 obtained in this way was 7 mm in diameter,
After processing to a thickness of about 3 mmt, the dielectric resonance method is used.
No load at resonance frequency (4-5GHz)
Q, relative permittivity ε_rAnd the temperature coefficient τ of the resonance frequency_fSeeking
I did. Table 1 shows the results.

Examples 2 to 6 Dielectric materials were prepared in the same manner as in Example 1 except that the powders of bismuth oxide, germanium oxide and silicon oxide were adjusted to the molar ratios shown in Table 1 and the sintering temperature was changed. A porcelain composition was manufactured and its properties were measured. Table 1 shows the results.
In the table, those marked with * are comparative examples outside the scope of the present invention.

[0013]

[Table 1]

[0014]

The dielectric porcelain composition of the present invention sinters at a low sintering temperature of 800 to 900 ° C. and has a large dielectric constant.
In addition, the unloaded Q is large, and the temperature change of the resonance frequency is small.
It can be applied to a dielectric substrate for C, a microwave laminated substrate, and the like. Further, since the dielectric ceramic composition of the present invention can be sintered at a lower temperature than in the past, Ag, Ag
-Lamination can be performed by simultaneous firing using Pd, Cu, or the like.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01B 3/12 307 C04B 35/495 H01P 7/10

Claims (1)

(57) [Claims] 1. A method according to claim 1, wherein 0.5 to 5.0% by weight of SiO ₂ is contained as a sub-component with respect to a main component comprising bismuth, germanium and oxygen represented by a composition formula of Bi ₁₂ GeO _20. Dielectric porcelain composition.