JP2902923B2 - High frequency dielectric ceramic 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 novel dielectric ceramic composition having a high dielectric constant and a high Q value in a high frequency range such as microwaves and millimeter waves.

[0002]

2. Description of the Related Art In the high frequency region such as microwaves and millimeter waves, dielectric ceramics are widely used for dielectric resonators, MIC dielectric substrates, and the like.

[0003] Conventionally, as this kind of dielectric porcelain,
For example, ZrO ₂ —SnO ₂ —TiO ₂ based material, BaO—
TiO ₂ materials, (Ba, Sr) (Zr, Ti) O ₃ -based materials, Ba (Zn, Ta) O ₃ -based materials and the like are known.
Hz to 5 GHz, permittivity 20 to 40, Q value is 10
00 to 3000, and temperature coefficient of resonance frequency (τf)
Has a characteristic near 0 ppm / ° C.

[0004]

However, recently, there has been a tendency to use higher frequencies and dielectric materials have been required to have more excellent dielectric properties, particularly to improve the Q value.

However, at present, the conventional dielectric materials described above do not have a practically high Q value in the operating frequency range of 10 GHz.

The present inventors have proposed a composition having a high dielectric constant and a high Q value in a high frequency region capable of meeting such a demand as a dielectric ceramic composition comprising a composite oxide containing BaO, MgO and WO _3. Things suggested earlier.

However, although a high Q value can be obtained with this dielectric ceramic composition, the temperature coefficient of resonance frequency (τ
Since f) is excessively deviated to the negative side, when used as a microwave dielectric porcelain material, there is a problem in practical use, such as the field of application thereof is limited.

[0008]

Means for Solving the Problems The present inventors have studied the above problems, and as a result, have found that BaO-MgO-WO
A composite oxide represented by _3, Y or Ti,, Zr, S
By including at least one element of n, Mn, Ca, Hf, La, Ce, Nd, Pr, and Sm at a predetermined ratio, a high Q value at 10 GHz (2
500 or more), and found that the temperature coefficient (τf) of the resonance frequency can shift from the minus side to the plus side, and have reached the present invention.

That is, the dielectric porcelain composition of the present invention contains at least Ba, Mg and W as metal elements, and a composition formula expressed by a molar ratio of these metal elements is xBaO · yM
When expressed as gO · zWO ₃ , x, y and z are 40
≦ x ≦ 55, 15 ≦ y ≦ 40, 20 ≦ z ≦ 30 (x + y
+ Z = 100) with respect to 100 parts by mol of the composition satisfying the condition of (+ z = 100).

Further, at least Ba, M
g, containing W, when expressed as xBaO · yMgO · zWO ₃ represented the formula in a molar ratio of these metal elements, the x, y and z are 40 ≦ x ≦ 55,15 ≦ y ≦ 40 ,
Ti, Zr, Sn, Mn, and C are relative to 100 mol parts of the composition satisfying 20 ≦ z ≦ 30 (x + y + z = 100).
It contains at least one element of a, Hf, La, Ce, Nd, Pr and Sm at a ratio of 0.1 to 20 mol parts.

In the present invention, the amount of each metal oxide constituting the main component is set in the above range because the Q value decreases when the BaO amount (x) is less than 40, and when the BaO amount (x) is more than 55, sintering occurs. This is because it becomes difficult. Also, the amount of MgO (y)
If it is less than 15, sinterability becomes difficult or the Q value decreases, and if it is more than 40, the Q value decreases. Further, if the amount of WO ₃ (z) is less than 20, the sinterability decreases, and if it exceeds 30, the Q value decreases.

Further, according to the present invention, the above BaO-Mg
Y is 0.1 to 100 mol part of the O-WO ₃ composition.
３０30 mol parts, or Ti, Zr, Sn, Mn, Ca,
By including at least one element of Hf, La, Ce, Nd, Pr, and Sm at a ratio of 0.1 to 20 mol parts, the temperature coefficient of the resonance frequency can be shifted to the plus side. The reason why the amount of these additives is limited to the above range is that the amount of Y is more than 30 mol parts or Ti, Zr, Sn, Mn, Ca, Hf, La, Ce, N
the amount of at least one of d, Pr and Sm is 2
If the amount is more than 0 mol part, the Q value is remarkably lowered, or Y or Ca causes a problem such that the temperature characteristic of the resonance frequency becomes too large on the positive side, and Y or Ti, Zr, or Sn is caused. , Mn, Ca, Hf, La, C
This is because when at least one of the elements e, Nd, Pr and Sm is less than 0.1 mol part, there is almost no effect of adding these elements.

According to the present invention, as a particularly desirable range, in order to maintain the Q value at 3000 or more, the above B
against aO-MgO-WO ₃ based composition 100 parts by mole,
When adding Y, 0.1 to 30 mol parts, Nd, L
a, Pr, Sm, Ce: 0.1 to 20 mol parts in the case of addition, Ca: 0.1 to 15 mol parts, Ti, Sn
In the case of Mn and Mn, it may be added in the range of 0.1 to 10 mol parts.

Further, the temperature coefficient τf of the resonance frequency is set to ± 3.
In order to control within 0 and to make the Q value 3000 or more, Y,
In the case of La, 0.1 to 20 mol parts, Nd, Pr, Sm
In this case, it is desirable to add 0.1 to 15 mol parts.

The presence of each of the elements Fe, Cr, V, Al and Si in the BaO-MgO-WO ₃ based dielectric composition tends to further increase the temperature coefficient of the resonance frequency to the minus side. Therefore, according to the present invention, the total amount of these metal elements, including impurities, is BaO-Mg.
It is desirable to control the amount to be 5 mol parts or less based on 100 mol parts of the main component composed of O-WO ₃ .

As a method for producing a porcelain based on the present invention, for example, an oxide of Ba, Mg, or W or a metal salt such as a carbonate or a nitrate which produces an oxide upon firing is prepared as a main raw material, , Zr, Sn, Mn, Ca, H
Prepare oxides such as f, La, Ce, Nd, Pr, Sm, and Y or metal salts such as carbonates and nitrates that generate oxides by firing, and weigh them so as to be in the above-described range. Mix well. Then, the mixture is 900
Calcination at ~ 1200 ° C and pulverization. Then, the calcined powder is formed into a predetermined shape by a known forming method such as press forming or a doctor blade method.

Next, the molded body is fired at 1300 to 1600 ° C. in an oxidizing atmosphere such as the air to obtain a dielectric ceramic.

[0018]

In the dielectric ceramic composition of the present invention, BaO, Mg
O, WO ₃ molar ratio and Y, or Ti, Zr, S
By changing the content of at least one element among n, Mn, Ca, Hf, La, Ce, Nd, Pr and Sm, the Q value at 10 GHz has a high characteristic of 2500 or more, and the resonance frequency It is possible to freely control the temperature coefficient from a minus side to a certain area on the plus side.

For example, in a porcelain composed of 50 mol% of BaO, 25 mol% of MgO and 25 mol% of WO ₃ , 10 GHz
Although the dielectric constant is 20 and the Q value is 12000, which is a high value at the measurement frequency, the temperature coefficient τf of the resonance frequency is -30 ppm and is large on the minus side. Therefore, according to the present invention, the temperature coefficient τf is reduced by −3 by adding the above-mentioned metal element.
It is possible to control from 0 ppm to the plus side.

[0020]

EXAMPLES As raw materials, BaCO ₃ and M having a purity of 99% or more were used.
gCO ₃ , WO ₃ and Ti, Zr, Sn, Mn, C
Using metal oxide powders of a, Hf, La, Ce, Nd, Pr, Sm, and Y, these were weighed in the proportions shown in Tables 1 to 8, and put together with water into a ball mill lined with rubber. For 8 hours. Next, after dehydrating and drying the mixture, it was calcined at 1000 ° C. for 2 hours, and the calcined product was wet-pulverized for 8 hours by putting water and an organic binder into a ball mill.

Thereafter, the pulverized material was dried, and then granulated through a No. 50 mesh net.
It was formed into a cylinder having a size of 10 mmφ × 5 mmt under a pressure of kg / cm ² . Furthermore, this column is
It was fired under the condition of 00 ° C. × 6 hours to obtain a porcelain sample.

With respect to the porcelain sample thus obtained, the relative dielectric constant (εr) and Q value at a frequency of 10 GHz were measured by the dielectric resonator method, and the temperature change of the resonance frequency in the temperature range from 25 ° C. to 85 ° C. Τf = (f (85 ° C.) − F (25 ° C.)) × 10 ⁶ / (f (25 ° C.) × (8
The temperature coefficient (τf) of the resonance frequency was calculated from 5 ° C-25 ° C)) (ppm / ° C). Here, f (85 ° C.) is a resonance frequency at 85 ° C., and f (25 ° C.) is a resonance frequency at 25 ° C.

The results are shown in Tables 1 to 8.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

[Table 5]

[0029]

[Table 6]

[0030]

[Table 7]

[0031]

[Table 8]

According to Tables 1 to 8, BaO, MgO, W
For the main component consisting of O ₃ , Y, or Ti, Zr,
Samples within the scope of the present invention to which at least one element of Sn, Mn, Ca, Hf, La, Ce, Nd, Pr and Sm are added all have a Q value at 10 GHz of 2500.
While having the above high characteristics, the temperature coefficient (τf) of the resonance frequency shifts from the minus side to the plus side,
It is understood that it can be arbitrarily controlled according to the amount of addition. In particular, when Y is added in an amount of 0.1 to 30 mol parts, when La, Ce, Nd, Pr, and Sm are added in an amount of 0.1 to 20 mol parts, when Zr is added in an amount of 0.1 to 20 mol parts, Ti is added. , Sn, and Mn are added at 0.1 to 10 mol parts, and when 0.1 to 15 mol parts are added, the temperature coefficient (τf) of the resonance frequency can shift from the minus side to the plus side, and The Q value can be maintained at a high value of 3000 or more. Further, Y and La are 0.1 to 20.
When mol parts are added, Nd, Pr and Sm are 0.1 to 15
When the molar part is added, the temperature coefficient (τf) is ± 30p
The characteristics of pm / ° C and Q value of 3000 or more can be obtained.

[0033]

As described in detail above, according to the present invention, B
By mixing a specific metal at a predetermined ratio with the main component consisting of aO, MgO, and WO ₃ , the Q value at 10 GHz has a high characteristic of 2500 or more, and the temperature coefficient (τf) of the resonance frequency is reduced. The temperature can be shifted from the minus side to the plus side, and the temperature coefficient can be freely controlled.

Thus, various resonator materials and MIs used in a frequency range such as microwaves and millimeter waves can be obtained.
It can be sufficiently applied to a dielectric substrate material for C and the like.

Claims (2)

(57) [Claims] 1. At least Ba, Mg, W as a metal element
When containing, expressed a composition formula expressed by the molar ratio of these metal elements and xBaO · yMgO · zWO _3, said x,
y and z are 40 ≦ x ≦ 55, 15 ≦ y ≦ 40, 20 ≦
Composition 10 that satisfies z ≦ 30 (x + y + z = 100)
A dielectric ceramic composition for high frequencies, comprising 0.1 to 30 mol parts of Y with respect to 0 mol parts. 2. At least Ba, Mg, W as a metal element
When containing, expressed a composition formula expressed by the molar ratio of these metal elements and xBaO · yMgO · zWO _3, said x,
y and z are 40 ≦ x ≦ 55, 15 ≦ y ≦ 40, 20 ≦
Composition 10 that satisfies z ≦ 30 (x + y + z = 100)
0 mol parts, Ti, Zr, Sn, Mn, Ca, H
A high frequency dielectric ceramic composition comprising at least one element selected from the group consisting of f, La, Ce, Nd, Pr, and Sm in a ratio of 0.1 to 20 mol parts.