JP3407523B2 - 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 ceramic composition used as a dielectric resonator in a high frequency region such as a microwave and a millimeter wave, and a dielectric ceramic used as a ceramic capacitor for temperature compensating electronic equipment. It relates to a composition.

[0002]

2. Description of the Related Art In recent years, dielectric ceramics have been used as dielectric resonators, dielectric filters and the like in communication devices utilizing electromagnetic waves in the microwave range, such as automobile phones, mobile phones and satellite broadcasting. In order to use a dielectric ceramic composition for such a dielectric component, in addition to having an appropriate permittivity suitable for the application and device, it has a low loss in the microwave region and a temperature change of the resonance frequency. Is small, that is, the temperature change of the dielectric constant is small. Conventionally, BaO-TiO ₂ series compounds have been known for such applications, and are disclosed in Japanese Patent Publication No. 58-20905. In addition, Ba (Zn _1/3 Ta _2/3 ) containing Nb and Ta
It is disclosed in JP-A-53-35454 that composite perovskite compounds represented by O ₃ exhibit particularly high Q.

[0003]

[Problems to be Solved by the Invention] However, the above B
In order to improve the Q value, the aO-TiO ₂ system requires a special and complicated manufacturing process in which the calcined product is treated with an acid solution or further annealed after firing. Further, the crystal phase is easily affected by the firing conditions, which causes a problem that the dielectric properties are likely to change, and it is difficult to control the properties. In addition, the above-mentioned Ba (Zn _1/3 Ta _2/3 )
The composite perovskite type typified by O ₃ has a small dielectric constant and cannot sufficiently meet the demand for miniaturization of the resonator. Further, since the firing temperature is as high as about 1500 ° C. or a long firing time of 50 hours or more is required, mass productivity is poor and the production cost due to energy required for firing is high. Was there.

The present invention solves the above problems and has a high dielectric constant, a high no-load Q value, and a small temperature coefficient of the resonance frequency, and the temperature coefficient of the resonance frequency is arbitrarily changed around zero. It is an object of the present invention to provide a dielectric ceramic composition that can be manufactured.

[0005]

In order to achieve this object, the dielectric ceramic composition of the present invention has a general formula Pr (Ti _1-x
Zr _x ) NbO ₆ (0 < x ≦ 0.6), and the above object can be achieved by this constitution.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is the general formula Pr (Ti _1-x Zr _x ) NbO ₆ (where 0 <
x ≦ 0.6), which is a dielectric porcelain composition,
It has the above dielectric constant (ε _r ) and the Q · f product of 25000 or more, and the temperature coefficient (τ _f ) of the resonance frequency whose absolute value is 100 ppm / ° C or less, and the temperature coefficient of the resonance frequency is centered around zero. It is possible to realize a dielectric ceramic composition that can be arbitrarily changed.

According to the invention defined in claim 2, the general formula Pr (T
i _1-x Zr _x ) NbO ₆ (0 < x ≤ 0.8) with respect to 100 parts by weight of the main component, Cr, Mn, and
At least one selected from oxides of Fe, Co, Ni and Cu is added to Cr ₂ O ₃ , MnO ₂ , Fe ₂ O ₃ and Co, respectively.
A dielectric ceramic composition containing 1.0 part by weight (excluding 0 part by weight) or less in terms of ₃ O ₄ , NiO and CuO, and containing Cr, Mn, Fe, and C
The inclusion of at least one oxide selected from o, Ni and Cu has the effect of densifying the porcelain and increasing the dielectric constant. It also acts as a sintering aid and has the effect of lowering the firing temperature and stabilizing the firing temperature dependence of the properties.

[0008]

【Example】

(Embodiment 1) Hereinafter, the first embodiment of the present invention will be described in detail.

The starting material is chemically high-purity Pr.
₆ O ₁₁ , TiO ₂ , ZrO ₂ and Nb ₂ O ₅ powders were weighed so as to have a predetermined composition ratio, put into a polyethylene ball mill, and added with stabilized zirconia boulders and pure water. Wet mixed for 20 hours. After wet mixing, dehydration and drying, put this dry powder in a crucible of high alumina,
It was calcined in air at 1100 ° C. for 2 hours. Next, this calcined powder was put into the same ball mill used for mixing together with pure water, wet pulverized for about 20 hours, and then dehydrated and dried. Next, an organic binder was added to this pulverized powder, and the mixture was mixed homogeneously, and then sized through a 32 mesh sieve, and the diameter was 13 m at a molding pressure of 1 ton / cm ² using a mold and a hydraulic press.
m and a thickness of 5 to 7 mm. Then, the molded body is put into an alumina-based sheath coated with zirconia powder, and is fired in air at a firing temperature of 1300 to 1500 ° C. for 2 to 50 hours to obtain the composition shown in sample numbers 1 to 12 of (Table 1). A dielectric porcelain was obtained.

[0010]

[Table 1]

Next, of the obtained sintered bodies, both surfaces of the sintered body which was fired at a temperature at which the density of the sintered body was the highest were polished, and the dielectric characteristics by microwave were measured. The measurement is performed by the dielectric resonator method, and the dielectric constant (ε _r ), Q · f product,
The temperature coefficient (τ _f ) of the resonance frequency was calculated. In the measurement of the dielectric constant and the Q value, the resonance frequency is 3.5 to 7.0GH
It was z. The temperature coefficient (τ _f ) of the resonance frequency is -25 to
It was measured in the range of 85 ° C.

The above measurement results are shown in (Table 1) for each sample number of 1 to 12. In Table 1, those marked with * are comparative examples outside the claims of the present invention. The reason for limiting the composition range of the dielectric ceramic composition of the present invention will be described with reference to (Table 1). As is clear from (Table 1), when Pr (Ti _1-x Zr _x ) NbO ₆ is represented as a general formula, by substituting a part of Ti with Zr, the dielectric constant is changed without significantly changing the Q value. It is possible to shift the temperature coefficient of the resonance frequency from 55 to 35 in the negative direction. Dielectric porcelain compositions (those not marked with *) in which the substitution amount (x) of Zr is within the composition range of 0.00 < x ≤ 0.60 have a dielectric constant of 35 or more and a high Q of 25,000 or more.・
It can be seen that the f product and the absolute value have a temperature coefficient of the resonance frequency in the range of 100 ppm / ° C. or less, and the temperature coefficient of the resonance frequency can be arbitrarily changed over a wide range around zero. In particular, the Zr substitution amount (x) is 0.
When it is 60, the dielectric constant is 36.3 and the Q · f product is 263.
At 80, the composition is such that the temperature coefficient of the resonance frequency is almost zero.
When the Zr substitution amount (x) exceeds 0.60, the sinterability is lowered and only porous porcelain can be obtained. At this time, the dielectric constant is reduced to 35 or less and the bending strength of the sintered body is reduced to 1.0 t / cm ² or less, resulting in a large decrease in mechanical strength, which is not practical. In this way, the composition range is limited.

(Second Embodiment) The second embodiment of the present invention will be described in detail below.

The starting material is chemically high-purity Pr.
₆ O ₁₁ , TiO ₂ , ZrO ₂ , Nb ₂ O ₅ , Cr ₂ O ₃ , Mn
O ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , NiO and CuO powders were weighed so as to have a predetermined composition ratio, and then a sintered body was prepared in the same manner as in Example 1 and its characteristics were evaluated. did.

The results are shown in Table 2 for each of the sample numbers 13 to 27.

[0016]

[Table 2]

In Table 2, those marked with * are books
It is a comparative example outside the claims of the invention. From this (Table 2)
As is apparent, the dielectric ceramic composition according to the present example has
Of Cr, Mn, Fe, Co, Ni and Cu as sub-components
At least one selected from the group consisting of oxides
By adding and containing
It should be possible to sinter and increase the dielectric constant without lowering the Qf product.
I understand. Also, by adding subcomponents,
The control range of the temperature coefficient of the resonance frequency is higher than that of the case without addition.
The enclosure further expands to the negative side and the degree of freedom in device design is great.
It also has the effect of making you feel better. The reason for limiting the composition range
This will be described with reference to (Table 2). First, it contains subcomponents
By doing so, the sinterability is improved. For this purpose the principal component set
Zr substitution amount (x) in the product up to 0.80
It becomes possible to obtain a dense sintered body. Ti more than this
When a part of Z is replaced with Zr, a parallax similar to that in Example 1 is obtained.
Only porcelain can be obtained. And the amount of the sub-component added is C
r₂O₃, MnO₂, Fe₂O ₃, Co₃O_Four, NiO and C
Converted to uO, 1.0 parts by weight (excluding 0 parts by weight)
In the following range, the Qf product and temperature characteristics will change significantly.
There is an effect that a high dielectric constant can be obtained without changing the structure. Also implemented
Although not shown in the example, even if two or more accessory components are added, the total
If the amount is 1.0 part by weight or less, the same effect is obtained.
It In some examples, the Zr substitution amount (x) is 0.
When it is 60, the dielectric constant is 39.5 and the Q · f product is 262.
There is a composition in which the temperature coefficient of the resonance frequency is almost zero at 00.
When the addition amount of the accessory component is 1.0 parts by weight or more, the secondary phase becomes
Since it precipitates from the grain boundary part and the Q · f product greatly decreases
The amount added is limited. In this way the composition range is limited
It is. The main component is calcined in advance,
The same effect can be obtained by adding

Further, in the method of manufacturing a dielectric ceramic according to the embodiment, Pr ₆ O ₁₁ , TiO ₂ , ZrO ₂ , Nb ₂ O ₅ and C are used.
r ₂ O ₃ , MnO ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , NiO and C
Although uO is used, the method is not limited to this method, and it is possible to use a compound such as Pr ₂ Ti ₂ O ₇ or a carbonate or hydroxide to obtain a desired composition ratio. The characteristics of can be obtained.

Furthermore, when the amount of the subcomponents added is small, it is easy to uniformly mix them by adding them as an aqueous solution.

[0020]

As described above, according to the present invention, when Pr (Ti _1-x Zr _x ) NbO ₆ is represented by the general formula, x
In the composition range limited to the range of 0.00 < x ≤ 0.60, a dielectric constant of 35 or more, a Q · f product of 25,000 or more, and a temperature coefficient of a small resonance frequency whose absolute value is 100 ppm / ° C. or less. The excellent dielectric ceramic composition of the present invention can be realized.

In addition, the microwave dielectric resonator and the temperature compensating ceramic capacitor using the dielectric ceramic composition of the present invention largely contribute to downsizing and high performance of communication equipment and electric equipment. Yes Industrial value is great.

Continuation of the front page (56) Reference JP-A-7-272537 (JP, A) JP-A-4-115409 (JP, A) JP-A-2-242524 (JP, A) JP-A-3-23257 (JP , A) А. И. КОМКОВ et al., ИДРОТ ЕРМАЛЪНЫЙ СИНТЕЭ И РЕНТГЕНОВСОЕ ИССЛ ЕДОВАНИ- , ДОКЛАДЫ А КАДЕМИИ НАУК СССР, Russia, 1962, No. 147 Volume, No. 3, pp. 687,688 (58) investigated the field (Int.Cl. ^7, DB Name) C04B 35/42-35/50 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. The general formula Pr (Ti _1-x Zr _x ) NbO.
A dielectric ceramic composition represented by ₆ (where 0 < x ≦ 0.6). 2. The general formula Pr (Ti _1-x Zr _x ) NbO.
₆ with respect to 100 parts by weight of the main component represented by (0 <x ≦ 0.8), Cr as a sub-component, Mn, Fe, Co, at least one or more of an oxide of Ni and Cu, respectively Cr ₂
O ₃ , MnO ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , NiO and CuO
The dielectric ceramic composition contained in the range of 1.0 parts by weight (excluding 0 parts by weight) or less.